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Energies 2022, volume 15, issue 5, March-1 2022,

Article number 1782.

Micro-Grid Oil Palm Plantation Waste Gasification

Power Plant in Indonesia: Techno-Economic and

Socio-Environmental Analysis

Jaka Isgiyarta 1,*, Bambang Sudarmanta 2, Jalu Aji Prakoso 3, Eka Nur Jannah 4 and Arif Rahman

Saleh 5,*

1. Tanggal 7 Desember 2021, Submission Received

2. Tanggal 14 Desember 2021, Assistant Editor Assigned

3. Tanggal 29 Desember 2021, Major Revisions

4. Tanggal 10 Januari 2022, English Editing

5. Tanggal 17 Januari 2022, Manuscript Resubmitted

6. Tanggal 17 Januari 2022, Revised Version Received

7. Tanggal 19 Januari 2022, Accepted for Publication

8. Tanggal 20 Januari 2022, Final Proofreading Before Publication

9. Tanggal 23 Januari 2022, 2nd Proof_ [Energies] Manuscript ID_ energies-1520840 - Final

Proofreading Before Publication

10. Tanggal 30 Januari 2022, Need Your Confirmation_ [Energies] Manuscript ID_ energies-

1520840

11. Tanggal 28 Februari 2022, doi_ 10.3390_en15051782. – Promotion Tips

12. Tanggal 28 Februari 2022, doi_ 10.3390_en15051782. Paper has been published

5/13/22, 2:49 PM Email Universitas Tidar - [Energies] Manuscript ID: energies-1520840 - Submission Received

https://mail.google.com/mail/u/0/?ik=2b096d038c&view=pt&search=all&permthid=thread-f%3A1718450806067777801&simpl=msg-f%3A1718450806… 1/2

arif rahman saleh <[email protected]>

[Energies] Manuscript ID: energies-1520840 - Submission Received 1 pesan

Editorial Office <[email protected]> 7 Desember 2021 08.59Balas Ke: [email protected]: arif rahman saleh <[email protected]>Cc: jaka isgiyarta <[email protected]>, bambang sudarmanta <[email protected]>, jalu aji prakoso<[email protected]>, eka nur jannah <[email protected]>

Dear Dr. rahman saleh,

Thank you very much for uploading the following manuscript to the MDPI submission system. One of our editors will be in touch with you soon.

Journal name: Energies Manuscript ID: energies-1520840 Type of manuscript: Article Title: Micro-grid Oil Palm Plantation Waste Gasification Power Plant in Indonesia: Techno-Economic and Socio-Environment Analysis Authors: jaka isgiyarta *, bambang sudarmanta, jalu aji prakoso, eka nur jannah, arif rahman saleh * Received: 7 December 2021 E-mails: [email protected], [email protected], [email protected], [email protected], [email protected]

You can follow progress of your manuscript at the following link (login required): https://susy.mdpi.com/user/manuscripts/review_info/7a41453be7c4d6da9937655248c2f5ca

The following points were confirmed during submission:

1. Energies is an open access journal with publishing fees of 2000 CHF for an accepted paper (see https://www.mdpi.com/about/apc/ for details). This manuscript, if accepted, will be published under an open access Creative Commons CC BY license (https://creativecommons.org/licenses/by/4.0/), and I agree to pay the Article Processing Charges as described on the journal webpage (https://www.mdpi.com/journal/energies/apc). See https://www.mdpi.com/about/openaccess for more information about open access publishing.

Please note that you may be entitled to a discount if you have previously received a discount code or if your institute is participating in the MDPI Institutional Open Access Program (IOAP), for more information see https://www.mdpi.com/about/ioap. If you have been granted any other special discounts for your submission, please contact the Energies editorial office.

2. I understand that:

a. If previously published material is reproduced in my manuscript, I will provide proof that I have obtained the necessary copyright permission. (Please refer to the Rights & Permissions website: https://www.mdpi.com/authors/rights).

b. My manuscript is submitted on the understanding that it has not been published in or submitted to another peer-reviewed journal. Exceptions to this rule are papers containing material disclosed at conferences. I confirm that I will inform the journal editorial office if this is the case for my manuscript. I confirm that all authors are familiar with and agree with

mailto:[email protected]





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5/13/22, 2:49 PM Email Universitas Tidar - [Energies] Manuscript ID: energies-1520840 - Submission Received


submission of the contents of the manuscript. The journal editorial office reserves the right to contact all authors to confirm this in case of doubt. I will provide email addresses for all authors and an institutional e-mail address for at least one of the co-authors, and specify the name, address and e-mail for invoicing purposes.

If you have any questions, please do not hesitate to contact the Energies editorial office at [email protected]

Kind regards, Energies Editorial Office St. Alban-Anlage 66, 4052 Basel, Switzerland E-Mail: [email protected] Tel. +41 61 683 77 34 Fax: +41 61 302 89 18

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5/13/22, 2:50 PM Email Universitas Tidar - [Energies] Manuscript ID: energies-1520840 - Assistant Editor Assigned



[Energies] Manuscript ID: energies-1520840 - Assistant Editor Assigned 1 pesan

Adelina Simon <[email protected]> 14 Desember 2021 13.13Balas Ke: [email protected]: arif rahman saleh <[email protected]>Cc: Adelina Simon <[email protected]>, jaka isgiyarta <[email protected]>, bambang sudarmanta<[email protected]>, jalu aji prakoso <[email protected]>, eka nur jannah <[email protected]>,Energies Editorial Office <[email protected]>


Your manuscript has been assigned to Adelina Simon for further processing who will act as a point of contact for any questions related to your paper.

Journal: Energies Manuscript ID: energies-1520840 Title: Micro-grid Oil Palm Plantation Waste Gasification Power Plant in Indonesia: Techno-Economic and Socio-Environment Analysis Authors: jaka isgiyarta *, bambang sudarmanta, jalu aji prakoso, eka nur jannah, arif rahman saleh *

Received: 07 December 2021 E-mails: [email protected], [email protected], [email protected], [email protected], [email protected]

You can find it here: https://susy.mdpi.com/user/manuscripts/review_info/7a41453be7c4d6da9937655248c2f5ca

Best regards, Ms. Adelina Simon Special Issue Editor, MDPI Avram Iancu str. 454, Cluj-Napoca, Romania Email: [email protected] Energies (IF: 3.004; http://www.mdpi.com/journal/energies) Linkedin: https://ch.linkedin.com/in/energies Twitter: @energies_MDPI Editor's Choice: https://www.mdpi.com/journal/energies/editors_choice

You are welcome to download your annual contribution report at https://susy.mdpi.com/user/manage_accounts

Disclaimer: MDPI recognizes the importance of data privacy and protection. We treat personal data in line with the General Data Protection Regulation (GDPR) and with what the community expects of us. The information contained in this message is confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this message in error, please notify me and delete this message from your system. You may not copy this message in its entirety or in part, or disclose its contents to anyone.








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5/13/22, 2:51 PM Email Universitas Tidar - [Energies] Manuscript ID: energies-1520840 - Major Revisions



[Energies] Manuscript ID: energies-1520840 - Major Revisions 4 pesan

Energies Editorial Office <[email protected]> 29 Desember 2021 15.56Balas Ke: [email protected]: arif rahman saleh <[email protected]>Cc: jaka isgiyarta <[email protected]>, bambang sudarmanta <[email protected]>, jalu aji prakoso<[email protected]>, eka nur jannah <[email protected]>, Energies Editorial Office <[email protected]>


Thank you again for your manuscript submission:

Manuscript ID: energies-1520840 Type of manuscript: Article Title: Micro-grid Oil Palm Plantation Waste Gasification Power Plant in Indonesia: Techno-Economic and Socio-Environment Analysis Authors: jaka isgiyarta *, bambang sudarmanta, jalu aji prakoso, eka nur jannah, arif rahman saleh * Received: 7 December 2021 E-mails: [email protected], [email protected], [email protected], [email protected], [email protected]

Your manuscript has now been reviewed by experts in the field. Please find your manuscript with the referee reports at this link:

https://susy.mdpi.com/user/manuscripts/resubmit/7a41453be7c4d6da9937655248c2f5ca

Please revise the manuscript according to the referees' comments and upload the revised file within 10 days.

Please use the version of your manuscript found at the above link for your revisions.

(I) Any revisions to the manuscript should be marked up using the “Track Changes” function if you are using MS Word/LaTeX, such that any changes can be easily viewed by the editors and reviewers. (II) Please provide a cover letter to explain, point by point, the details of the revisions to the manuscript and your responses to the referees’ comments. (III) If you found it impossible to address certain comments in the review reports, please include an explanation in your rebuttal. (IV) The revised version will be sent to the editors and reviewers. Please confirm if Table 6 needs copyright permission. You can find in the system you paper with our Journals template, please make your revision on that version of your paper.

If one of the referees has suggested that your manuscript should undergo extensive English revisions, please address this issue during revision. We propose that you use one of the editing services listed at https://www.mdpi.com/authors/english or have your manuscript checked by a native English-speaking colleague.

Do not hesitate to contact us if you have any questions regarding the revision of your manuscript. We look forward to hearing from you soon.

Kind regards, Ms. Adelina Simon







https://www.mdpi.com/authors/english



Special Issue Editor, MDPI Avram Iancu str. 454, Cluj-Napoca, Romania Email: [email protected] Energies (IF: 3.004; http://www.mdpi.com/journal/energies) Linkedin: https://ch.linkedin.com/in/energies Twitter: @energies_MDPI Editor's Choice: https://www.mdpi.com/journal/energies/editors_choice



arif rahman saleh <[email protected]> 7 Januari 2022 06.46Kepada: [email protected]

Dear Ms. Adelina Simon

First of all, I would like to thank you for the opportunity you have been given. Currently, I have made revisions accordingto the suggestion from the reviewer, but when I was going to submit the revision version, the submission status wasEnglish Pre Editing so I couldn't upload the revised version of the article. For this condition, I ask for more information.Thank you Manuscript detail:Manuscript ID: energies-1520840 Type of manuscript: Article Title: Micro-grid Oil Palm Plantation Waste Gasification Power Plant in Indonesia: Techno-Economic and Socio-Environment Analysis Authors: jaka isgiyarta *, bambang sudarmanta, jalu aji prakoso, eka nur jannah, arif rahman saleh *

best regard Arif Rahman Saleh, ST., MTProgram Studi Teknik MesinFakultas TeknikUniversitas Tidar email: [email protected], [email protected]: 082386085001

[Kutipan teks disembunyikan]

Adelina Simon <[email protected]> 7 Januari 2022 13.06Kepada: arif rahman saleh <[email protected]>Cc: [email protected], [email protected], [email protected], [email protected],[email protected]

Dear Dr. Rahman,

Thank you very much for your email. You paper current status is "English Pre Editing", can you please confirm if you or one co-authors have applied for editing services?

I'm looking forward to hearing from you.










Kind regards,

Ms. Adelina Simon Special Issue Editor, MDPI Romania Avram Iancu str. 454, Cluj-Napoca, Romania Email: [email protected] Energies (IF: 3.004; http://www.mdpi.com/journal/energies) Linkedin: https://www.linkedin.com/company/energies-mdpi/ Twitter: @energies_MDPI Editor's Choice: https://www.mdpi.com/journal/energies/editors_choice

Geological and Thermodynamic Analysis of Low Enthalpy Geothermal Resources to Electricity Generation Using ORC and Kalina Cycle Technology http://www.mdpi.com/1996-1073/13/6/1335

Prediction of Performance Variation Caused by Manufacturing Tolerances and Defects in Gas Diffusion Electrodes of Phosphoric Acid (PA)–Doped Polybenzimidazole (PBI)-Based High-Temperature Proton Exchange Membrane Fuel Cells http://www.mdpi.com/1996-1073/13/6/1345


On 1/7/2022 1:46 AM, arif rahman saleh wrote: > Dear Ms. Adelina Simon > > First of all, I would like to thank you for the opportunity you have > been given. Currently, I have made revisions according to the suggestion > from the reviewer, but when I was going to submit the revision version, > the submission status was English Pre Editing so I couldn't upload the > revised version of the article. For this condition, I ask for more > information. Thank you > Manuscript detail: > Manuscript ID: energies-1520840 > Type of manuscript: Article > Title: Micro-grid Oil Palm Plantation Waste Gasification Power Plant in > Indonesia: Techno-Economic and Socio-Environment Analysis > Authors: jaka isgiyarta *, bambang sudarmanta, jalu aji prakoso, eka nur > jannah, arif rahman saleh * > > > best regard > *Arif Rahman Saleh, ST., MT* > /*Program Studi Teknik Mesin*/ > /Fakultas Teknik/ > /*Universitas Tidar */ > /email: [email protected] > <mailto:[email protected]>, [email protected] > <mailto:[email protected]>/ > /mobile: 082386085001/ > > > Pada tanggal Rab, 29 Des 2021 pukul 15.56 Energies Editorial Office > <[email protected] <mailto:[email protected]>> menulis: > > Dear Dr. rahman saleh,



https://www.linkedin.com/company/energies-mdpi/


http://www.mdpi.com/1996-1073/13/6/1335

http://www.mdpi.com/1996-1073/13/6/1345









> > Thank you again for your manuscript submission: > > Manuscript ID: energies-1520840 > Type of manuscript: Article > Title: Micro-grid Oil Palm Plantation Waste Gasification Power Plant in > Indonesia: Techno-Economic and Socio-Environment Analysis > Authors: jaka isgiyarta *, bambang sudarmanta, jalu aji prakoso, eka > nur > jannah, arif rahman saleh * > Received: 7 December 2021 > E-mails: [email protected] > <mailto:[email protected]>, [email protected] > <mailto:[email protected]>, > [email protected] <mailto:[email protected]>, > [email protected] <mailto:[email protected]>, > [email protected] <mailto:[email protected]> [Kutipan teks disembunyikan]> Email: [email protected] <mailto:[email protected]> > Energies (IF: 3.004; http://www.mdpi.com/journal/energies > <http://www.mdpi.com/journal/energies>) > Linkedin: https://ch.linkedin.com/in/energies [Kutipan teks disembunyikan]

arif rahman saleh <[email protected]> 9 Januari 2022 14.56Kepada: Adelina Simon <[email protected]>Cc: [email protected], "[email protected]" <[email protected]>, Jalu Aji Prakoso<[email protected]>, [email protected], [email protected]

Yes, I confirm. I have confirmed with the co-author and he is trying to submit English editing. However, the process has not beencompleted because what was submitted is not the result of our final revision. Is it possible if the revision upload processcan be reopened and the files that are included in the english editing process are the files we just revised? thank you

Arif Rahman Saleh, ST., MTProgram Studi Teknik MesinFakultas TeknikUniversitas Tidar email: [email protected], [email protected]: 082386085001



















5/13/22, 2:57 PM Email Universitas Tidar - [Energies] Manuscript ID: energies-1520840 - English Editing



[Energies] Manuscript ID: energies-1520840 - English Editing 1 pesan

Adelina Simon <[email protected]> 10 Januari 2022 16.38Kepada: arif rahman saleh <[email protected]>Cc: [email protected], "[email protected]" <[email protected]>, Jalu Aji Prakoso<[email protected]>, [email protected], [email protected]

Dear Dr. Rahman,

Thank you for your email. When the English editing will be done, you will received an email with a link where you can download you paper.

Feel free to contact me, should you require any further informations!

Kind regards,

Ms. Adelina Simon Special Issue Editor, MDPI Romania Avram Iancu str. 454, Cluj-Napoca, Romania Email: [email protected] Energies (IF: 3.004; http://www.mdpi.com/journal/energies) Linkedin: https://www.linkedin.com/company/energies-mdpi/ Twitter: @energies_MDPI Editor's Choice: https://www.mdpi.com/journal/energies/editors_choice

Geological and Thermodynamic Analysis of Low Enthalpy Geothermal Resources to Electricity Generation Using ORC and Kalina Cycle Technology http://www.mdpi.com/1996-1073/13/6/1335

Prediction of Performance Variation Caused by Manufacturing Tolerances and Defects in Gas Diffusion Electrodes of Phosphoric Acid (PA)–Doped Polybenzimidazole (PBI)-Based High-Temperature Proton Exchange Membrane Fuel Cells http://www.mdpi.com/1996-1073/13/6/1345


On 1/9/2022 9:56 AM, arif rahman saleh wrote: > Yes, I confirm. > I have confirmed with the co-author and he is trying to submit English > editing. However, the process has not been completed because what was > submitted is not the result of our final revision. Is it possible if the > revision upload process can be reopened and the files that are included > in the english editing process are the files we just revised? thank you > > *Arif Rahman Saleh, ST., MT* > /*Program Studi Teknik Mesin*/ > /Fakultas Teknik/





http://www.mdpi.com/1996-1073/13/6/1335

http://www.mdpi.com/1996-1073/13/6/1345



> /*Universitas Tidar */ > /email: [email protected] > <mailto:[email protected]>, [email protected] > <mailto:[email protected]>/ > /mobile: 082386085001/ > > > Pada tanggal Jum, 7 Jan 2022 pukul 13.06 Adelina Simon > <[email protected] <mailto:[email protected]>> menulis: > > Dear Dr. Rahman, > > Thank you very much for your email. > You paper current status is "English Pre Editing", can you please > confirm if you or one co-authors have applied for editing services? > > I'm looking forward to hearing from you. > > Kind regards, > > Ms. Adelina Simon > Special Issue Editor, MDPI Romania > Avram Iancu str. 454, Cluj-Napoca, Romania > Email: [email protected] <mailto:[email protected]> > Energies (IF: 3.004; http://www.mdpi.com/journal/energies > <http://www.mdpi.com/journal/energies>) > Linkedin: https://www.linkedin.com/company/energies-mdpi/ > <https://www.linkedin.com/company/energies-mdpi/> > Twitter: @energies_MDPI > Editor's Choice: > https://www.mdpi.com/journal/energies/editors_choice > <https://www.mdpi.com/journal/energies/editors_choice> > > Geological and Thermodynamic Analysis of Low Enthalpy Geothermal > Resources to Electricity Generation Using ORC and Kalina Cycle > Technology > http://www.mdpi.com/1996-1073/13/6/1335 > <http://www.mdpi.com/1996-1073/13/6/1335> > > Prediction of Performance Variation Caused by Manufacturing Tolerances > and Defects in Gas Diffusion Electrodes of Phosphoric Acid (PA)–Doped > Polybenzimidazole (PBI)-Based High-Temperature Proton Exchange Membrane > Fuel Cells > http://www.mdpi.com/1996-1073/13/6/1345 > <http://www.mdpi.com/1996-1073/13/6/1345> > > Disclaimer: MDPI recognizes the importance of data privacy > and protection. We treat personal data in line with the > General Data Protection Regulation (GDPR) and with what the > community expects of us. The information contained in this > message is confidential and intended solely for the use of > the individual or entity to whom they are addressed. If you > have received this message in error, please notify me and > delete this message from your system. You may not copy this > message in its entirety or in part, or disclose its contents > to anyone. > > On 1/7/2022 1:46 AM, arif rahman saleh wrote: > > Dear Ms. Adelina Simon > > > > First of all, I would like to thank you for the opportunity you have > > been given. Currently, I have made revisions according to the > suggestion > > from the reviewer, but when I was going to submit the revision > version,















http://www.mdpi.com/1996-1073/13/6/1335

http://www.mdpi.com/1996-1073/13/6/1335

http://www.mdpi.com/1996-1073/13/6/1345

http://www.mdpi.com/1996-1073/13/6/1345



> > the submission status was English Pre Editing so I couldn't upload the > > revised version of the article. For this condition, I ask for more > > information. Thank you > > Manuscript detail: > > Manuscript ID: energies-1520840 > > Type of manuscript: Article > > Title: Micro-grid Oil Palm Plantation Waste Gasification Power > Plant in> > Indonesia: Techno-Economic and Socio-Environment Analysis > > Authors: jaka isgiyarta *, bambang sudarmanta, jalu aji prakoso, > eka nur> > jannah, arif rahman saleh * > > > > > > best regard > > *Arif Rahman Saleh, ST., MT* > > /*Program Studi Teknik Mesin*/ > > /Fakultas Teknik/ > > /*Universitas Tidar */ > > /email: [email protected] > <mailto:[email protected]> > > <mailto:[email protected] > <mailto:[email protected]>>, [email protected] > <mailto:[email protected]> > > <mailto:[email protected] > <mailto:[email protected]>>/ > > /mobile: 082386085001/ > > > > > > Pada tanggal Rab, 29 Des 2021 pukul 15.56 Energies Editorial Office > > <[email protected] <mailto:[email protected]> > <mailto:[email protected] <mailto:[email protected]>>> menulis: > > > > Dear Dr. rahman saleh, > > > > Thank you again for your manuscript submission: > > > > Manuscript ID: energies-1520840 > > Type of manuscript: Article > > Title: Micro-grid Oil Palm Plantation Waste Gasification Power > Plant in> > Indonesia: Techno-Economic and Socio-Environment Analysis > > Authors: jaka isgiyarta *, bambang sudarmanta, jalu aji > prakoso, eka > > nur > > jannah, arif rahman saleh * > > Received: 7 December 2021 > > E-mails: [email protected] > <mailto:[email protected]> > > <mailto:[email protected] > <mailto:[email protected]>>, [email protected] > <mailto:[email protected]> > > <mailto:[email protected] <mailto:[email protected]>>, > > [email protected] <mailto:[email protected]> > <mailto:[email protected] <mailto:[email protected]>>, > > [email protected] <mailto:[email protected]> > <mailto:[email protected] <mailto:[email protected]>>, > > [email protected] > <mailto:[email protected]> > <mailto:[email protected] > <mailto:[email protected]>> > > > > Your manuscript has now been reviewed by experts in the field. > > Please find > > your manuscript with the referee reports at this link:



































> > > > > https://susy.mdpi.com/user/manuscripts/resubmit/7a41453be7c4d6da9937655248c2f5ca > <https://susy.mdpi.com/user/manuscripts/resubmit/7a41453be7c4d6da9937655248c2f5ca> > > > <https://susy.mdpi.com/user/manuscripts/resubmit/7a41453be7c4d6da9937655248c2f5ca > <https://susy.mdpi.com/user/manuscripts/resubmit/7a41453be7c4d6da9937655248c2f5ca>> > > > > Please revise the manuscript according to the referees' > comments and > > upload > > the revised file within 10 days. > > > > Please use the version of your manuscript found at the above link > > for your > > revisions. > > > > (I) Any revisions to the manuscript should be marked up using the > > “Track > > Changes” function if you are using MS Word/LaTeX, such that any > > changes can > > be easily viewed by the editors and reviewers. > > (II) Please provide a cover letter to explain, point by point, the > > details of > > the revisions to the manuscript and your responses to the > referees’ > > comments. > > (III) If you found it impossible to address certain comments> in the > > review > > reports, please include an explanation in your rebuttal. > > (IV) The revised version will be sent to the editors and > reviewers. > > Please confirm if Table 6 needs copyright permission. > > You can find in the system you paper with our Journals template, > > please make> > your revision on that version of your paper. > > > > If one of the referees has suggested that your manuscript should > > undergo> > extensive English revisions, please address this issue during > > revision. We > > propose that you use one of the editing services listed at > > https://www.mdpi.com/authors/english > <https://www.mdpi.com/authors/english>> > <https://www.mdpi.com/authors/english > <https://www.mdpi.com/authors/english>> or have your manuscript > > checked by a > > native English-speaking colleague. > > > > Do not hesitate to contact us if you have any questions > regarding the > > revision of your manuscript. We look forward to hearing from > you soon. > > > > Kind regards, > > Ms. Adelina Simon > > Special Issue Editor, MDPI > > Avram Iancu str. 454, Cluj-Napoca, Romania > > Email: [email protected] <mailto:[email protected]> > <mailto:[email protected] <mailto:[email protected]>> > > Energies (IF: 3.004; http://www.mdpi.com/journal/energies > <http://www.mdpi.com/journal/energies> > > <http://www.mdpi.com/journal/energies > <http://www.mdpi.com/journal/energies>>)



















> > Linkedin: https://ch.linkedin.com/in/energies > <https://ch.linkedin.com/in/energies> > > <https://ch.linkedin.com/in/energies > <https://ch.linkedin.com/in/energies>> > > Twitter: @energies_MDPI > > Editor's Choice: > > https://www.mdpi.com/journal/energies/editors_choice > <https://www.mdpi.com/journal/energies/editors_choice> > > <https://www.mdpi.com/journal/energies/editors_choice > <https://www.mdpi.com/journal/energies/editors_choice>> > > > > You are welcome to download your annual contribution report at > > https://susy.mdpi.com/user/manage_accounts > <https://susy.mdpi.com/user/manage_accounts> > > <https://susy.mdpi.com/user/manage_accounts > <https://susy.mdpi.com/user/manage_accounts>> > > > > Disclaimer: MDPI recognizes the importance of data privacy > > and protection. We treat personal data in line with the > > General Data Protection Regulation (GDPR) and with what the > > community expects of us. The information contained in this > > message is confidential and intended solely for the use of > > the individual or entity to whom they are addressed. If you > > have received this message in error, please notify me and > > delete this message from your system. You may not copy this > > message in its entirety or in part, or disclose its contents > > to anyone. > > >













5/13/22, 2:57 PM Email Universitas Tidar - [Energies] Manuscript ID: energies-1520840 - Manuscript Resubmitted



[Energies] Manuscript ID: energies-1520840 - Manuscript Resubmitted 1 pesan

Energies Editorial Office <[email protected]> 17 Januari 2022 16.49Balas Ke: Adelina Simon <[email protected]>, Energies Editorial Office <[email protected]>Kepada: arif rahman saleh <[email protected]>Cc: jaka isgiyarta <[email protected]>, bambang sudarmanta <[email protected]>, jalu aji prakoso<[email protected]>, eka nur jannah <[email protected]>


Thank you very much for resubmitting the modified version of the following manuscript:



A member of the editorial office will be in touch with you soon regarding progress of the manuscript.

Kind regards, Energies Editorial Office Postfach, CH-4020 Basel, Switzerland Office: St. Alban-Anlage 66, CH-4052 Basel Tel. +41 61 683 77 34 (office) Fax +41 61 302 89 18 (office) E-mail: [email protected] https://www.mdpi.com/journal/energies/

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Energies 2022, 15, x. https://doi.org/10.3390/xxxxx www.mdpi.com/journal/energies

Article

Micro-Grid Oil Palm Plantation Waste Gasification Power Plant

in Indonesia: Techno-Economic and


Jaka Isgiyarta 1,*, Bambang Sudarmanta 2, Jalu Aji Prakoso 3, Eka Nur Jannah 4 and Arif Rahman Saleh 5,*

1 Department of Accounting, Faculty of Economics and Business, Diponegoro University,

Semarang, Indonesia 2 Department of Mechanical Engineering, Faculty of Engineering, Institut Teknologi Sepuluh Nopember,

60111 Surabaya, Indonesia; [email protected] 3 Department of Economic Development, Faculty of Economics, Universitas Tidar, 56116 Magelang, Indone-

sia; [email protected] 4 Department of Agrotechnology, Faculty of Agriculture, Universitas Tidar, 56116 Magelang, Indonesia;

[email protected] 5 Department of Mechanical Engineering, Faculty of Engineering, Universitas Tidar, 56116 Magelang, Indo-

nesia

* Correspondence: [email protected] (J.I.); [email protected] (A.R.S.)

Abstract: The utilization of new and renewable energy sources explicitly based on biomass needs

to be increased to reduce dependence on fossil fuels. One of the potential biomasses of plantation

waste in Indonesia that can be utilized is oil palm plantation waste in the form of fronds and trunks

that are converted with multi-stage downdraft gasification technology. This study aimed to con-

duct a technical analysis, economic analysis, investment risk analysis, social analysis, and an en-

vironmental impact assessment of power plants fueled by oil palm plantation waste. The method

used was the upscaling of a prototype of a 10 kW power plant to 100 kW. The results showed that it

was technically and economically feasible to apply. The economic indicators were a positive NPV

of USD 48.846 with an IRR of 9.72% and a B/C ratio of 1.16. The risk analysis predicted a probability

of an NPV 49.94% above the base case. The study of the social aspects suggested that the construc-

tion of power plants has a positive impact in the form of increased community income and the

growth of new economic sectors that utilize electricity as a primary source. An analysis of the en-

vironmental effects is critical so that the impacts can be minimized. Overall, the construction of

small-scale power plants in oil palm plantations is worth considering as long as it is carried out

following the applicable regulations.

Keywords: gasification; multi-stage; techno-economic; power plant; oil palm waste

1. Introduction

The availability of clean energy is necessary to meet national energy needs to effi-

ciently support the goal of the sustainable development of new and renewable energy in

Indonesia. By 2025, it is expected that the renewable energy mix can grow to 23% with an

installed capacity of 5500 MWe as shown in Figure 1. Until 2018, the percentage of re-

newable energy utilization reached 6.2%. The bioenergy sector is expected to contribute

8.2% to national energy, one way of which is through the development of bioenergy

power plants [1]. The utilization of new and renewable energy has become a topic of

interest and is on the agenda in the world as one of the solutions to overcome the prob-

lems of the current energy crisis. The cause of this energy crisis is the decreasing availa-

bility of fossil fuels. Biomass, because of its abundant availability, can substitute for the

Citation: Isgiyarta, J.; Sudarmanta,

B.; Prakoso, J.A.; Jannah, E.N.; Saleh,

A.R. Micro-Grid Oil Palm Plantation

Waste Gasification Power Plant in

Indonesia: Techno-Economic and

Socio-Environmental Analysis.

sEnergies 2022, 15, x.

https://doi.org/10.3390/xxxxx

Academic Editor(s):

Received: 7 December 2021

Accepted: 19 January 2022

Published: date

Publisher’s Note: MDPI stays neu-

tral with regard to jurisdictional

claims in published maps and insti-

tutional affiliations.

Copyright: © 2022 by the authors.

Submitted for possible open access

publication under the terms and

conditions of the Creative Commons

Attribution (CC BY) license

(https://creativecommons.org/license

s/by/4.0/).

Energies 2022, 15, x FOR PEER REVIEW 2 of 23

use of fossil fuels. Compared to other renewable energy sources (wind, solar, etc.), energy

production from biomass requires lower capital investment costs [2]. To encourage the

acceleration of the use of renewable energy in Indonesia, the government has established

various policies. The government has the target of an additional installed capacity from

renewable energy power plants of 905.73 megawatts (MW), consisting of 196 MW from

geothermal powerplants, 557.93 MW from hydro power plants, 138.8 MW from solar

power plants, and 13 MW from bio power plants. Meanwhile, the renewable energy in-

vestment target in 2021 will increase to USD 2.05 billion or approximately IDR 28.9 tril-

lion (assuming an exchange rate of IDR 14,100 per dollar) from the investment achieve-

ment in 2020, which amounted to USD 1.36 billion or approximately IDR 19.2 trillion.

Some of the government’s policies on new energy are as follows [3]:

a. Implementation of the mandatory B30 program for all sectors, followed by the de-

velopment of biodiesel trials as a substitute for fossil diesel with B100 (biodiesel

100%) development technology;

b. Mixing of research octane number 92 Oil Fuel in East Java in the context of efforts to

procure bioethanol-type biofuel, in accordance with the Regulation of the Minister

of Energy and Mineral Resources Number 12 of 2015;

c. Acceleration of waste power plant development in 12 selected cities, as mandated by

Presidential Regulation Number 35 of 2018 concerning the acceleration of waste

power plant development programs;

d. Encouraging the use of rooftop solar power plants in accordance with the mandate

of the Minister of Energy and Mineral Resources Regulation Number 49 of 2018

concerning the Use of Rooftop Solar Power Generation Systems by state power plant

consumers;

e. Simplifying the bureaucratic process through the of Energy and Mineral Resources

Online Licensing Application, which is integrated with data on natural resources,

operations, production, and marketing/sales of each type of energy;

f. Increasing the use of renewable energy to reduce dependence on fossil fuels, which

will have an impact on increasing Indonesia’s economic stability.

Figure 1. Primary energy supply by 2025.

The utilization of biomass waste into energy can be a solution to reduce dependency

on fossil fuel. The potential energy from biomass is currently at 32,654 MW and 1716.5

MW has been developed [4]. Development of bioenergy-based power plants (on-grid)

until 2013 reached 90.5 MW, while for those off-grid it reached 1626 MW [5]. One of the

most significant biomass potentials in Indonesia is from solid waste from oil palm plan-

tations. Oil palm plantations in Indonesia are the largest source of biomass with a total

electricity energy that can be generated of 5495 MWe [6]. The sources come from planta-

28%

23% 28%

21%

Renewable Energy Oil Coal Gas


tion wastes (oil palm fronds and oil palm trunks) or waste from oil palm mill production

(meso scrap fiber, palm kernel shell, and oil palm mill effluent). However, not all these

wastes are utilized as energy, so they have the potential to become sources of greenhouse

gas emissions when they decompose. In addition, in terms of the environment in recent

years, the oil palm plantation industry in Indonesia has been in the European Union’s

and the United States’ spotlight because it is considered an industry that is not environ-

mentally friendly due to the impact it causes [7]. If the renewable energy target policy is

implemented by 2030, it is expected to reduce greenhouse gas emissions by 29% com-

pared to 2010.

Indonesia has five provinces with the most extensive oil palm plantations, namely,

South Sumatra, Central Kalimantan, West Kalimantan, North Sumatra, and Riau. In 2019,

the Indonesian State Electricity Company reported that Indonesia’s electrification ratio

had reached 99%. However, the electrification ratio is still calculated from the number of

people who obtain electricity for access to lighting and not for the productive sector. The

Ministry of Energy reported the data on villages that did not have access to electricity to

be as many as 2281 villages out of a total of 232,128 villages in Indonesia [1]. Meanwhile,

for the five provinces with the most extensive oil palm plantations, there are 785 villages,

2510 villages, 13,595 villages, 634 villages, and 5209 villages, respectively, as shown in

Figure 2. The condition is ironic, since these five provinces produce much of the oil palm

plantation waste. At present, access to electricity only benefits people in urban areas

where there is an installed electricity network. In contrast, construction of the network

constrains those plantations because the cable must pass through the plantations. Thus,

the issue of land acquisition is a significant factor in the lack of access to electricity in

rural communities located in oil palm plantations.

Figure 2. Villages that have no access to electricity in Indonesia.

Oil palm plantation wastes are oil palm fronds and oil palm trunks. Oil palm fronds

during pruning and replantation activities are always stacked and collected at an average

production rate of 9.8 t-dry/ha-estate/year and 14.9 t-dry/ha-replantation/year. A study

reported that oil palm fronds contain 25.5% (dry basis) hemicellulose material, which has

excellent potential to be used as a raw material for biofuels and bio-based material pro-

duction [8–11]. Oil palm trunks are the second type of biomass residue produced during

replanting. Oil palm trunk production is estimated at 62.8 t-dry/ha-replantation/year. At

present, oil palm fronds are usually burned as fuel in processing plants, and the re-

mainder is disposed of in plantations, while oil palm trunks after the replanting process

are not utilized [10]. Utilization of oil palm waste as a raw material for renewable energy

that can generate electricity is a solution to the residue of oil palm industry activities in


Indonesia. According to the Ministry of Energy and Mineral Resources of the Republic of

Indonesia, the renewable energy market in Indonesia is not yet optimal because it relies

on solar panels which have components that are imported. Thus, the government is

pushing a draft Indonesian Presidential Regulation that will regulate the price of new

renewable electricity. Through this policy, it is hoped that the production of renewable

energy that utilizes oil palm waste as a raw material can grow in oil palm industrial areas

in Indonesia. In addition, the push for the use of renewable energy is in line with the

global commitment to the 7th point of the Sustainable Development Goals that are to be

achieved by 2030 regarding clean and affordable energy.

One technology that can be used to convert biomass into alternative energy without

producing emissions is gasification [12]. Gasification is the process of converting solid or

liquid raw materials into thermochemical gases [13]. Different to combustion, gasification

produces higher efficiency, and the pollutants are still below emissions standards. The

gasification process consists of several sequential stages, namely, the drying, pyrolysis,

partial oxidation, and reduction stages. Gasification requires media such as air, oxygen,

or water vapor. The gas produced from the gasification process, commonly called syn-

thetic gas (syngas), consists of combustible syngas (i.e., CO, H2, and CH4) and

non-combustible gas (i.e., CO2, N2, and the remaining O2) [14]. Gasification reactions oc-

cur in a reactor called a gasifier. There are various types of gasifiers such as updraft,

downdraft, cross draft, bubbling fluidized bed gasifiers, and circulating fluidized beds

(CFBs) [15]. One type of gasifier that is widely used is the downdraft [16–18]. A

downdraft gasifier has the advantage of a high carbon conversion rate, low tar produc-

tion, and simple construction compared to other types [19].

The aim of this study was to analyze the utilization of oil palm plantation waste as

fuel in gasification power plants. The analyses simultaneously carried out were technical,

economic, investment risk, social, and environmental impact analyses. Oil palm planta-

tion wastes used were oil palm fronds and oil palm trunks. Both of these plantation

wastes have been reported by several previous studies and are suitable as feedstock for

gasification. The power plant analyzed was upscaled from a laboratory-scale prototype

with a capacity of 10 kW, which has been reported in previous studies, to a small-scale

power plant with a capacity of 100 kW. The gasification technology used the multi-stage

downdraft gasifier [20]. This technology has the advantage of being able to produce

syngas with a high–low heating value and a low tar content of 2.6 times compared to the

single-stage downdraft gasifier that has been reported in other studies. Moreover, this

multi-stage gasification technology was also equipped with an air heating system that

was also capable of producing low tar content up to 27.8 mg/Nm3 and temperature in-

creases at the partial oxidation zone with a constant equivalent ratio [18].

Several previous studies using gasification technology for power generation have

been carried out. Romaniuk [21]conducted research by utilizing agricultural waste as fuel

in gas generators. Modification of the gas generator was conducted by adjusting the

supply of oxidizer (air supply) into the reaction zone. A downdraft-type gasification

power plant with a capacity of 25 kW was also developed by ENTRAGE Energies System

AG, using a 4.3 L six-cylinder petrol engine coupled to an electric generator. A

downdraft-type gasification power plant was also developed by ALL POWER LABS with

a power output of 15 kW [21,22]. The gasifier was coupled to a four-cylinder diesel en-

gine and an electric generator. Currently, one of the largest biomass power plants is lo-

cated in the UK, near Cheshire, and it produces 21.5 MW of electrical energy. A gasifica-

tion power plant with a capacity of 100 kW in current market conditions is more profita-

ble than a larger capacity provided that the fuel used is not difficult to supply [23]. Si-

tumorang [24] reports that gasification power plants can be used to utilize locally avail-

able biomass as fuel with a generating capacity of less than 200 kW.

Before the power plant was implemented, it was necessary to evaluate the feasibility

and sustainability of the project in terms of economic, social, and environmental as well

as the risk variables that could hinder the success of the project. Some analyses that


needed to be conducted were techno-economic, risk, and social–environmental. Tech-

no-economic analyses of gasification power plants have been carried out in several pre-

vious studies. Porcu [25] conducted a techno-economic analysis of a gasification power

plant being upscaled from 500 to 200 kW using a bubbling fluidized bed gasifier. Singh

conducted a techno-economic analysis of hybrid power plants between gasification, solar

PV, and fuel cells, but the gasification technology used was not mentioned. Economic

and environmental impact analyses of an 11 MW capacity gasification power plant were

carried out by Cardoso [23], and the results of the study reported that the NPV was in-

fluenced by revenue from electric sales. Sobamowo [26]conducted a techno-economic

analysis of a gasification power plant using downdraft gasification technology with a

capacity of 60 MW; the results of the study reported that the distance between the power

plant and the source of raw materials affected the raw material costs. Moreover, local

materials for capital investment, maintenance, and fuel costs provided higher profit

margins.

Emiliano [27,28] conducted a techno-economic assessment of power plants with

gasification technology. The results of the study reported that the price of gaseous fuel

(i.e., natural gas) dramatically affects the economics of the power plant project. In addi-

tion, power efficiency and the selling price of electricity can produce a higher NPV. Cali

[29] conducted a techno-economic analysis of the FOAK industrial gasification plant. The

results of the study reported that the cost of fuel dramatically affects the cost of electricity

(COE), and the economic results can be increased by technical development to reduce

operating costs. Kivumbi [30] conducted a techno-economic analysis of a gasification

power plant with a capacity of 425 kW using municipal solid waste as fuel. The results of

the study reported that for small-scale power plants, a high interest rate causes the return

on investment to be longer, so it is not appropriate. In addition, the distance between the

source of raw materials and power plants affects the total cost of transportation to in-

crease the cost of electricity production. Gokalp [31] conducted a techno-economic anal-

ysis of a gas tire scrap power plant capacity of 5 MWe. The gasification technology used

was a circulating fluidized bed. The results of the study reported that the price of raw

materials dramatically influences the financial result, but if it cannot be reduced, the ef-

ficiency of the gasification system needs to be increased. Based on the results of the pub-

lished techno-economic analyses, various variables affect the financial results of a gasi-

fication power plant and are different for each region, the type of raw material used, and

the planned generating capacity. Moreover, most publications only discuss the economic

analysis, and only a few discuss investment, social, and environmental risk analyses

simultaneously, while these are interrelated. The generating capacity analyzed was also

medium- to large-scale, while for the microscale, the literature is still limited.

This research is critical because of the limitations in the literature on technical and

economic analyses; specifically, it was a small-scale 100 kW gasification power plant that

utilized oil palm plantation waste as the primary fuel. In this study, the technical analysis

carried out to calculate the capacity of the gasification system was based on the type of

solid fuel and internal combustion engine. Meanwhile, the economic analysis conducted

was calculated as the net present value (NPV), internal rate of return (IRR), bene-

fit-to-cost ratio (B/C), and payback period (PBP). The investment risk was also analyzed

using the Monte Carlo method. Furthermore, the final analysis carried out was an anal-

ysis of the social and environmental impacts due to the gasification power plant.

2. Materials and Methods

Multi-stage gasification power plant experiments have been carried out previously

at the pilot scale with a capacity of 10 kW [18,20,32]. To estimate the economic value of a

power plant on a micro-grid scale, in the analysis, the capacity was upscaled to 100 kW.

The aim was to obtain the difference between the non-profit models on the prototype

scale and a profitable model on a commercial scale. The results of the pilot-scale experi-

ment were used as a reference for modeling the performance of microscale gasification

Comment [ARS1]: I have been

remove the citation number 31,

please revise


power plants. The technical aspects discussed in this study are feedstock characteriza-

tions using ultimate and proximate analyses, explanations of experimental activities, and

analysis of economic models. Techno-economic analyses were carried out including in-

vestment costs and operating costs. Meanwhile, for the technical analysis, the size of the

biomass power plant was upscaled. Furthermore, an income analysis was carried out

based on financial assumptions. After the technical aspects were defined, the next step

was to perform an economic analysis and socio-environmental analysis. The Monte Carlo

method was used for the risk analysis with Crystal Ball software Version 11.1.2.4®.

2.1. Multi-Stage Downdraft Gasification Power Plant

The experiments of pilot-scale gasification were conducted using a single-throat

downdraft gasifier that was modified from a single-stage to a multi-stage [18]. The ad-

vantage of this multi-stage gasifier is that it produces syngas with a lower tar content and

a higher heating value. The multi-stage gasification technology was developed in the

combustion laboratory and an energy system from the Institut Teknologi Sepuluh

Nopember. The scheme of the gasification system is shown in Figure 3.

Figure 3. Prototype of a multi-stage downdraft gasifier.

The solid fuel consumption of this reactor was 8 kg/h. Before entering the reactor,

the fuel was placed inside a hopper equipped with a screw conveyor. The amount of fuel

entering was regulated through the screw rotation of the screw conveyor. The air used

was ambient air, and before entering the gasifier, it was preheated until 200 °C. In addi-

tion to obtaining external heating, the air was also internally heated inside the gasifier by

placing an air ring in the form of a pipe that circled the inner wall of the reactor. In the

first stage, the air was injected into the pyrolysis zone using six nozzles. The air in this

pyrolysis zone initiated the oxidation reaction between the air and carbon, called oxida-

tive pyrolysis [20,33–36]. The oxidation reaction released heat so that the pyrolysis

properties changed from endothermal to exothermal. This was advantageous because the

released heat from the partial oxidation zone was reduced. The temperature increased in

the pyrolysis zone cracking the tar components from primary to secondary tar [18].

Furthermore, at the second stage, the air was injected in the partial oxidation, pre-

cisely above the throat. In this position, the air was not distributed using the air ring be-


cause it was heated from the oxidation region. Finally, in the third stage, the air entered

the reduction zone using an air ring divided by six nozzles. Air entering the reduction

zone also reacted with residual charcoal in that zone; as a result, the temperature in the

reduction zone also increased, which was beneficial for the thermal cracking reaction of

the tar component. In addition, air also activates the residual charcoal so that the number

of pores becomes more numerous and can capture some of the tar components [20,37,38].

Gasifier walls are built using stainless-steel plates with a thickness of 3 mm. The to-

tal height of the reactor was 1.3 m with a diameter of 0.5 m. The ash sweeping mechanism

was placed above the grate to prevent blockage of the grate hole. The sweeper was

moved every 15 min after syngas under flammable conditions. The ash that fell from the

grate was moved to the box using a screw conveyor with a 45° slope. After that, periodic

ash disposal was carried out every 3 h of operation. Syngas was emitted from the gasifier

before being used in the internal combustion engine and first passed through the cyclone

to separate heavy particles, such as ash and fine grains, that were carried out by the

syngas. Heavy particles were separated due to the fact of gravity, and the syngas was

cleaned using a dry filter. Inside the dry filter there were two layers of filter media: the

lowest layer was activated carbon, and the top layer was wood dust. The tar component

carried in the syngas was captured by the activated carbon. The syngas temperature

coming out of the gasifier was 150 °C and 27 °C after it passed the dry filter. The tar and

heavy oil components contained in the syngas were condensed and absorbed by acti-

vated carbon. The layer of sawdust served as an additional layer to capture the unfiltered

tar and heavy oil in the activated carbon layer. To ensure the filtering efficiency and the

final tar content, the syngas was tested by taking a sampling gas every 30 min of opera-

tion. Syngas was condensed using a condenser with ice water as cooling media. The

condensed tar stuck to the wall of the condenser and moved down and was accommo-

dated with a measuring cup [40]. The gas that was separated from the tar was later stored

in a gas sampling bag and tested separately using gas chromatography.

Furthermore, syngas was channeled to a diesel engine that was connected to a 10

kW electric generator with dual fuel operating condition (i.e., syngas and diesel fuel).

Syngas entered the diesel engine via the air intake channel through the mixer, and the

amount was regulated using a valve.

2.2. Feedstock Characterization

The raw materials used were oil palm fronds and oil palm trunks that were shred-

ded into fibers with lengths of 3–5 cm as shown in Figure 4. Characterization was con-

ducted by testing the raw material using ultimate and proximate analyses. The test was

carried out at the Energy Institute Laboratory of the Institut Teknologi Sepuluh

Nopember. Proximate analysis refers to the ASTM D 5142-04 standard for the parameters

of moisture, volatiles, and ash. Meanwhile, fixed carbon was tested based on the differ-

ence between the total mass reduced by moisture, volatiles, and ash. The ultimate analy-

sis was carried out according to the ASTM D 5373-02 standard for carbon, hydrogen,

oxygen, nitrogen, and sulfur components. The oxygen was the difference between the

total mass minus the previous component. Analysis of the calorific value was carried out

using a bomb calorimeter (AC-350 Bomb Calorimeter) according to the ASTM D4809-18

for analysis of gross calorific value. Ultimate analysis uses sample sizes between 100 and

300 g to obtain accurate results. Carbon, nitrogen, and sulfur testing in this study used a

sample size of 2–3 mg, which had an error tolerance of 0.05 w. (500 ppm) with an uncer-

tainty below 0.02 w.%. Based on the manufacturer’s specification data from the equip-

ment used, the uncertainty of the instrument was in the moderate concentration range of

0.3 w.%. If the sample had a carbon content higher than 90 w.%, then the tolerance was

extended to 0.5 w.%. The results of the analysis of the feedstock are presented in Table 1.

Comment [M2]: incorrect ref

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Figure 4. Results of the shredded midrib and oil palm stems.

Table 1. Ultimate and proximate analyses of solid fuel.

Analysis Contents (% Mass) Oil Palm Frond Oil Palm Trunk

Proximate

Volatile 85.1 86.7

Moisture 70.6 75.6

Ash 3.37 3.35

Calorific Value (MJ/kg) 17.48 17.41

Ultimate

Carbon 48.43 51.41

Hydrogen 10.46 11.82

Oxygen 46.75 51.16

Nitrogen 12.40 0.17

2.3. Experimental Activity

Gasification experiments were carried out using a multi-stage downdraft gasifier.

The used equivalent ratio (ER) was the optimum ratio from previous studies [20,31]

which was 0.4 while the air ratio (AR) for the pyrolysis zone, partial oxidation, and re-

duction were selected at the optimum ratio of 10%, 80%, and 10%. The AR percentage

shows the amount of air entering for each zone, meaning that from the total air based on

ER 0.4 divided into three locations, 10% into the pyrolysis zone, 80% into partial oxida-

tion, and 10% into the reduction zone. Syngas was cleaned using a cyclone and dry filter

to further flow into a diesel engine. The experimental data generated from the gasifica-

tion experiment are shown in Table 2.

Table 2. Prototype of the gasification power plant specification of a 10 kW capacity.

Parameter Value

Equivalent ratio 0.4

Air ratio (pyrolysis, oxidation, and reduction zone) 10%, 80%, 10%

Feedstock flow rate 8 kg/h

Air inlet temperature 200 °C

Syngas temperature after cleaning 80 °C

Syngas flow rate 0.0028 m3/s

Syngas heating value (LHV) 6.642 MJ/Nm3

Syngas Composition Volumetric Percentage

CO 18%

H2 25%

CH4 4%


2.4. Economic Model

The economic analysis in this study was carried out using a 10 kW capacity gasifi-

cation experimental data reference that was upscaled to 100 kW. Some operating condi-

tions were equated according to the experimental reference data, and the resulting data

were used as input data for the economic analysis. A techno-economic analysis was car-

ried out for every year of the estimated service life of the gasification system of 20 years.

The reference cost component started from the capital cost to the estimated revenue for

each year.

3. Result

3.1. Techno-Economic Analysis

In this study, the analysis was conducted for the utilization of oil palm plantation

waste converted into electrical energy using gasification technology in Indonesia. The

analysis was conducted close to the actual condition, and the analysis was carried out

based on a literature study that was conducted for potential bioenergy investment, espe-

cially biomass in Indonesia.

The oil palm plantation waste was grouped into two types, namely, waste from

plantations in the form of oil palm fronds and trunks and waste from the processing of oil

palm into crude oil palm such as fiber, shells, empty fruit bunches, and liquid waste or oil

palm mill effluent (POME) [8]. From all types of plantation waste, the most significant

potential was oil palm fronds with a total production of 49.41 million tons/year which

were derived from the Sumatra region; 23.50 million tons/year in Kalimantan; 218 thou-

sand tons/year in Java, Bali, and Madura; 2.17 million tons/year in Sulawesi; and 202.64

thousand tons/year in Papua. The total energy that can be generated from all the poten-

tial reaches 5495 Mwe [6]. Palm fronds were chosen because they are always available on

plantations and do not require a significant supply cost compared to other wastes. The

waste from palm processing was owned by the company, so that if the community or

other parties needed it, they must buy it first, while oil palm fronds can be taken for free

and only require costs for transportation, chopping, and drying. Besides the oil palm

fronds, oil palm trunk is also used as additional raw materials. However, due to the fact

that it is only available during the replanting process, the amount was less if it was di-

vided within one year. The total potential energy from oil palm trunk reaches 815 MW

[6].

The first step for the raw material for oil palm fronds before use was to strip the

leaves, then transport them to the power plant storage facility. The next step was to shred

and dry them under the sun and then finally store them in a warehouse. The oil palm

fronds were used as the primary fuel, and the oil palm trunks were use as the secondary

fuel. When both were available, they were mixed with a percentage of 70% fronds and

30% trunk. The power plant was ideally placed close to the location of the plantation so

that the cost of the transportation of the raw materials could be reduced [23]. Based on

the planned installed capacity, 1189 tons/day of raw materials were needed. Thus, at least

100 hectares of oil palm plantation were required. When compared with the areas of

lands in Sumatra, Kalimantan, Sulawesi, and Papua, this plant can be placed anywhere

because the existing land area was greater than the required minimum land area. The

maximum moisture content of the solid fuel was 40%.

Actually, the oil palm fronds are not purely waste. So far, they have been left piling

up beside the palm trees until they rot and become soil fertility. However, to reach this

stage requires a long time. Thus, to maintain balance, not all the fronds produced were

used entirely. As much as 70% of the waste was utilized, and the remaining 30% was left

as soil fertilizers. Although the availability of the land area was quite extensive, most of

the landowners were companies, while a limited amount was owned by the community.

Cooperation between the power plant manager and the company was needed to ensure

the availability of raw materials and the sustainability of the power plant in the future.




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removed citation number 40


The biomass power plant with gasification technology was expected to operate for 20

years with a construction period of one year. The plant works 355 days a year and has a

ten-day shutdown schedule for maintenance.

Following its capacity, the number of employees needed to operate the power plant

was estimated at six people, consisting of one manager, two operators, two technicians,

and one administrator. Economic analysis was conducted by predicting the cost compo-

nents associated with power plant construction, starting from the planning stage to the

implementation stage.

3.1.1. Investment Cost

The investment costs were calculated based on an investment analysis for power

plants of the same scale used as a reference in this study. The power plant with a capacity

of 10 kW was built in 2017. All costs were converted from IDR to USD. The exchange rate

in 2019 for USD 1 was IDR 14,012.73, while the IDR to USD currency exchange rate in the

year the reference power plant project was IDR 13,693. The breakdown of capital costs

refers to the IRENA [42] and are presented in Table 3.

Table 3. Investment costs (USD).

Investment Item Cost

Civil work 664.31

Building 763.96

Foundation and supporting material 4417.68

Piping system 2524.39

Electric component 2989.40

Instrumentation 1660.78

Insulation and painting 664.31

Total Construction Cost 13,684.83

Gasifier with cleaning and cooling system 30,000.00

Diesel engine (100 kVA) 12,458.25

Total Investment Cost 56,143.08

3.1.2. Operating Cost

The operating cost component was the costs incurred each year for power plants,

which consisted of raw material costs (consisting of costs for providing raw materials and

transportation), operating and maintenance costs (O&M), tax burden, and annual depre-

ciation costs. Operating and maintenance costs included the costs of providing electricity,

clean water, ash disposal, engine component replacement, and the gasifier component.

This also included costs for labor, consisting of basic salaries, benefits, and health insur-

ance. Office operational costs consisted of administrative costs, office stationery, official

travel, and transportation costs. Electricity needs for plant operations were calculated

based on the number of operating hours for one year. Details of the cost of electricity

needs for the plant are presented in Table 4.

Table 4. Yearly production costs (USD).

Item Cost

Operation and maintenance of the gasifier 2245.72

Operation and maintenance of the gasifier variable cost 139.86

Depreciation cost 2930.39

Total Yearly Production Cost 5315.97




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reference list


The cost component of the solid fuel is the cost of collecting, cutting, and transpor-

tation from the source of the solid fuel to the location of the power plant. Oil palm fronds

are not purchased but rather harvested from trees, collected, and transported. The cost

component was harvesting, transportation, and labor costs, while for oil palm trunk, the

costs incurred were logging costs. Costs incurred to produce electricity were calculated

based on the standard O&M cost for diesel engines from IRENA 2018 of $0.008/kWh [42].

The O&M cost component for diesel engines was obtained by multiplying yearly electric

production by the standard O&M cost from IRENA. Fuel costs consisted of biomass and

diesel because they were operated in dual fuel. The percentage of syngas substitution

against diesel was a maximum of 60%. Details of the electricity production costs are

presented in Table 5.

Table 5. Electric production cost (USD).

Item Cost

O&M cost of diesel engine (electric production) 2401.75

Yearly production cost 5315.97

Depreciation cost (20 year operation) 265.80

Biomass fuel cost 6574.44

Diesel fuel cost 10,313.23

Total Electric Production Cost 24,871.19

3.2. Gasifier Upscaling

The capacity of the power plant that was analyzed economically was 100 kW. Based

on the technical aspects, the diesel engine and gasifier were upgraded. The selected diesel

engine was Cummins 6BT5,962, which was coupled with a 100 kVA generator. The

technical specifications can be seen in Table 6.

Table 6. Diesel engine specifications [43].

Engine Cummins 6BT5.9G2

Generator Stamford UCI274C

KVA 100

KW 80

Number of cylinders 6

Bore x stroke 102 × 120 mm

Piston disp. 5900 L

Fuel consumption 17 L/h (75% load) and 22 L/h (100% Load)

Oil capacity 16.4 L

Dimension 2910 × 1110 × 1450 mm

Based on the engine specifications, the output capacity was calculated using the

method by Kivumbi [30] with the results shown in Table 7.

Table 7. Diesel engine parameters.

Parameter Value Unit

Maximum air producer gas 0.0738 m3

Maximum real producer gas intake 0.0351 m3/s

Real producer gas intake 0.0281 m3/s

The normal volume rate of the producer gas 0.0287 m3/s

Thermal power 190.4284 kW

Maximum mechanical output 82.0746 kW

Maximum electrical output 34.9638 kW




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between.


changed citation number from

42 to 43, please revised


Furthermore, after the capacity of the diesel engine was known, the specifications of

the gasifier could be calculated using the method used by Kivumbi [23] with the results


Table 8. Gasifier sizing parameters.


Thermal power consumption (full load) 272.0406 kW

High heating value 24,132.7205 kJ/kg

Low heating value 19,766.0645 kJ/kg

Biomass consumption 0.0138 kg/s

Specific fuel consumption 1.4171 kg/kWh

Gas production from the gasifier 0.1106 m3/s

Cross-sectional area 0.0442 m2

The diameter of the air inlet 0.2374 m

Height from nozzle plane 0.1139 m

Diameter of firebox 0.4985 m

Nozzle diameter 0.0094 m

Specific gasification rate 1120.0607 kg/h·m2

Height of gasifier 3.5002 m

Gasifier diameter 0.2374 m

Based on the parameters of the diesel engine and gasifier that were calculated, the

electrical energy output capacity was calculated, and the results obtained are presented

in Table 9. The number of operating days for one year was assumed to be 355 days, with

42.6% electricity production efficiency. Total electricity production per day was 839.13

kWh/day, so that the total electricity production for one year is 297,891.57 kWh/year.

Table 9. Electric production parameters.


Electric output 34.96 kW

Electrical efficiency 42.60 %

Frequency 50 Hz

Number of gas engine 1 Unit

Daily electric production 839.13 kWh/day

Day operation in one year 355 Day

Yearly electric production 297,891.57 kWh/year

3.3. Revenues

Revenue was obtained by multiplying the total electricity production for one year

with the price of electricity following the state power plant standard for renewable en-

ergy, which was $0.121/kWh. Electricity consumption costs for the plant reduced gross

revenue. Detailed calculations for the power plant are presented in Table 10.

Table 10. Revenue list.

Revenue Item Revenue Unit

Electric price 0.121 USD/Kwh

Estimated revenue 36,004.56 USD/year

Plant usage in electricity 686.511 USD/year

Net revenue 35,318.05 USD/year


3.4. Financial Assumption

The financial assumptions used in this study included the operating life of the plant

and the interest rate presented in Table 11. Each year, it was estimated that all costs and

selling prices would experience inflation of 2% [26]. The net present value was calculated

using an interest rate of 8%.

Table 11. Financial assumption.

Assumption Item Value Unit

Power plant lifetime 20 year

Interest rate 8 %

Inflation rate 2 %

3.5. Economic Feasibility Analysis

An economic feasibility study was carried out to decide whether the investment in

the power plant that is to be carried out was profitable and feasible for investment. The

conducted economic analysis was the NPV, PBP, and the IRR. The NPV calculation was

conducted by calculating the present value of cash flows for a certain period. The calcu-

lated cash flow was the difference between the benefits and costs for each year the NPV

was determined. The equation to calculate the NPV is shown below [23]:

∑ (( ) )

( ) ( )

where i is the interest rate, N is the number of periods (years), Cy are number of cash in-

flows in year y, and Cy = 0 is the total investment of the first year plus cash outflows. In-

terest rates were used to calculate the discount factor and present values for costs and

benefits. The operating period was assumed to be 20 years [25] with an interest rate of

8%. After calculating, if the NPV was positive, the investment was profitable and vice

versa. Thus, if t was profitable, capital costs could be returned during the operating pe-

riod.

The internal rate of return was analyzed based on the accumulation of NPV values.

IRR is the present value of costs and benefits. Investment can be made if the IRR value is

higher than the interest rate and vice versa. The equation used to calculate IRR was as

follows [23]:

( )

The initial investment cost is the total investment cost in the first year, i is the interest

rate, and y is the current year. The payback period was analyzed to determine the cost for

each year so that the initial investment costs could be returned. The equation used to

calculate the payback period is as follows [23]:

Risk analysis on the choice of inputs was used to generate electricity per kWh using

a standard deviation approach. The approach tries to categorize the different input types

of fuel from oil palm waste for mechanization of energy generation. The equation used

for calculating the standard deviation was as follows:

√

∑ ̅



The economic analysis was carried out on a power plant that was scaled up from 10

kW to 100 kW. A sensitivity analysis was carried out by looking at the effect of the per-

centage increase in construction costs, the price of biomass fuel, and the price of diesel

fuel on the economic value of the project. The sensitivity analysis of the investment costs

to produce each kWh of electricity was also varied to determine the investment costs that

could produce an internal rate of return higher than the interest rate. In addition, a risk

analysis was also carried out to see the effect of investment costs and operating costs on

NPV [25].

3.6.1. Economic and Sensitivity Analysis

Based on the results of economic analysis, power plant investment can reach a break

event point in the 6th year as shown in Figure 5. With an interest rate base of 8%, the net

present value was positive after accumulating for 20 years of operation at USD 48,846 as

shown in Table 12, which means this power plant project provides benefits. The ratio

between cost and benefit was greater than 1, at 1.16. Meanwhile, the internal rate of re-

turn was also above the interest rate of 9.72%, so the investment was still profitable. The

cost of electricity was still below the selling price from the state power plant of USD

0.083/kWh, where the selling price from the government was USD 0.121/kWh, so there

was a difference of USD 0.037/Kwh as profit.

The sensitivity analysis was performed using the Crystal Ball software Version

11.1.2.4® with 100,000 trials. The feature used was the decision table tool [45,46]. With this

feature, we could simulate several different values or two decision variables. Interest

rates varied from 7% to 12%. The results of this analysis are presented in Table 12. The

NPV continued to decrease along with the increase in the interest rate, but the value re-

mained positive. The same trend also occurred in the IRR and B/C ratio. Even though the

NPV was always positive, and the B/C ratio was above 1, the results showed that when

the interest rate was at 10–12%, the IRR was already below the interest rate. Thus, in-

vestment had a percentage return that was greater than the interest rate if the interest rate

was lower or equal to 9%. However, the value of the interest rate was a fluctuating value

depending on the economic conditions of the Indonesian state.

Table 12. NPV, IRR, and B/C ratio forecast with interest rate variation.

Interest Rate 7% 8% 9% 10% 11% 12%

NPV (USD) 57,096 48,846 41,514 34,975 29,124 23,873

IRR (%) 10.75 9.72 8.71 7.73 6.76 5.80

B/C ratio 1.18 1.16 1.15 1.13 1.12 1.10

LCOE ($0.083/kWh)




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Figure 5. Return on investment based on the operating life of the power plant.

Investment costs were also varied to determine the range of investment costs that

still provided benefits. The range of investment costs, according to IRENA was from USD

950 to 1650/kW [42]. If one looks at the comparison of the investment costs in Table 13, in

the range from USD 950 to 1100/kW, it was still profitable because the IRR was above the

interest rate. Meanwhile, above USD 1100/kW, it was no longer profitable because the

IRR was under the base interest rate. In this study, the investment cost, which was the

base case, was USD 950/kWh.

Table 13. NPV, B/C ratio, and IRR with investment cost variation.

Investment Cost

(USD/kWh) 950 1100 1250 1400 1550 1650

NPV (USD) 48,846 44,681 40,515 36,350 32,184 29,407

B/C ratio 1.16 1.15 1.13 1.12 1.10 1.09

IRR (%) 9.72 8.64 7.62 6.67 5.76 5.18

The solid fuel that used for gasification was oil palm frond and oil palm trunk.

When compared for the two fuels, as shown in Table 14, oil palm trunk resulted in a

higher NPV and IRR, which means that it was profitable to use oil palm trunk as fuel. The

cost for oil palm trunk was $0.025/kg, while oil palm frond was $0.026/kg. The difference

was because the oil palm frond requires additional harvesting costs for each period while

the palm trunk does not. However, the use of oil palm frond and oil palm trunk is still

profitable. The difference is only in the profit margin. However, the price for diesel fuel

was a maximum at $0.47/L or the price of subsidies from the government, so that IRR was

above 8%.

Table 14. IRR with Variation of Diesel Fuel and Solid Fuel Price.

Diesel Fuel Price (USD/L) (0.40) (0.47) (0.55) (0.62) (0.69)

Oil palm trunk (USD/kg) 0.025 12.77 9.95 7.04 4.00 0.74

Oil palm Frond (USD/kg) 0.026 12.55 9.72 6.80 3.75 0.47

The effect of diesel fuel price and the interest rate on IRR was also analyzed, and the

results are presented in Table 15. The diesel fuel price used as the base case was the price

of a subsidy. If there was an increase in the price of subsidies, the investment remains

-9

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1

6

11

16

21

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

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ow

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Comment [ARS19]: This

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profitable, as long as the maximum price of diesel fuel is $0.47/L, with a maximum in-

terest rate of 9%. This power plant was calculated to implement small villages with low

to medium economic levels, and electricity was not used for extensive commercial activ-

ities. Thus, it was possible to use diesel fuel at a subsidized price as long as the price was

no more than the maximum price above. If the price and interest rate were to exceed, the

IRR value was under the base case of interest rate. The existence of subsidies from the

government is very influential on the benefits to be obtained from a power plant project.

In addition, the subsidy policy can also attract investors to make investments [8,42,44].

Table 15. IRR with variations in the diesel fuel price and interest rate.

Diesel Fuel Price (USD/L) 0.40 0.47 0.55 0.62 0.69

Interest rate

7% 13.60 10.75 7.80 4.72 1.41

8% 12.55 9.72 6.80 3.75 0.47

9% 11.52 8.71 5.82 2.80 (0.45)

10% 10.50 7.73 4.86 1.86 (1.36)

11% 9.51 6.76 3.92 0.94 (2.25)

12% 8.53 5.80 2.99 0.04 (3.12)

The effect of feed-in tariffs on the NPV, B/C Ratio, and IRR was analyzed, and the

results are presented in Table 16. The simulation results of the feed-in tariff was below

the base case of USD 0.12/kWh, the IRR was under the base case of interest rate. Thus, if

there was a decrease in feed-in tariffs from the government under the base case, invest-

ment in power plants does not provide optimal benefits. Based on the pattern of in-

creasing feed tariffs in Indonesia to date, it always increases over a specified period.

Thus, the feed-in tariff can be assumed not to reduce return of investment period because

the value continues to increase. However, decreases were still possible depending on

changes in subsidies and political decisions.

Table 16. NPV, B/C Ratio, and IRR with variations of the feed in tariff.

Feed in Tariff

(USD/kWh) 0.102 1.110 0.117 0.124 0.131

NPV (USD) (4581) 16,371 37,323 58,275 79,227

B/C Ratio 0.98 1.05 1.13 1.20 1.27

IRR (%) (1.04) 3.48 7.57 11.44 15.18

3.6.2. Financial Risk Analysis

Financial risk assessment was carried out to evaluate the effect of economic param-

eters on investment risk. The risk analysis of the power plant project was carried out

using Crystal Ball software®. This software was chosen because of the ease of operation,

and it is compatible with MS Excel® [45]. Another advantage, was that various types of

data distribution can be chosen according to needs. The simulation was conducted with

1,000,000 iterations. The Monte Carlo method was used for the risk analysis as it calcu-

lates with the technique of statistical sampling, operates with random input components,

and has uncertainty [25]. The input variable was simulated with several iterations and

produced several data in the form of probabilities. The normal probability distribution

was used. The selection of a probability distribution model in the Monte Carlo analysis

was essential because it affects the accuracy of the simulation results [44,47]. In addition,

the number of iterations must also be adjusted to obtain convergence. With a greater

number of iterations, the mean and standard deviation will be evenly distributed.

The risk analysis was carried out to look at the effect of capital cost, O & M cost, and

revenue on NPV, IRR, and the B/C Ratio. They were assumed with a probability of 90%

using a normal distribution and a standard deviation of 1% from the base case. Figures 6–




between.




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changed this citation number to

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changed citation number to 44




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8 show the forecast capital cost, O&M cost, and revenue. The results of the risk analysis

are shown with a 90% confidence level and a 10% failure rate [25] that over the past 20

years, the NPV range obtained was from USD 41,833 to 55,861. NPV was estimated to

have an increase of 49.94% from the base case during the operating period of the plant,

which means the power plant project can provide benefits to investors.

Meanwhile, the IRR with a 90% probability obtained between 8.40% and 11.04%,

which means it was still higher than the interest rate. The percentage of IRR higher than

the base case was 50.02%, and the percentage of IRR higher than the interest rate was

98.42%. B/C ratio forecast with 90% probability was obtained from 1.14% to 1.19% and

had a percentage greater than the base case of 60.28%. Based on the results of the risk

analysis, the probability of investment risk was relatively small because the NPV was

always positive, and the IRR had the higher base case interest rate. Besides, with a 50%

chance of NPV above the base case, results were very promising for investors because the

estimated profits obtained during the operating life of the power plant were higher.

Figure 6. Effect of capital costs, O&M costs, and revenue on IRR.

Figure 7. Effect of capital costs, O&M cost, and revenue on the B/C ratio.




between.




Figure 8. Effect of capital costs, O&M cost, and revenue on net present value.

Based on the risk analysis of components that affect NPV, 68% of the most signifi-

cant influence was investment cost, while capital cost and revenue were the remainders.

Thus, if the investor can control and reduce investment costs, then it was possible to ob-

tain higher profits. The investment component that was possible to be reduced was the

capital cost of the gasification system. The investment cost was 74.4%, as shown in Figure

9. The gasification system used was foreign-made or made with imported products.

Considering the pilot-scale development experience that has been done, it was possible

to produce gasification systems independently so that investment costs can be reduced.

Figure 9. Sensitivity analysis of the investment cost components.

Furthermore, to determine the type of fuel that was able to produce the largest kWh

with low risk, standard deviation analysis was used. The analysis can provide infor-


mation in the form of the types of raw materials used to produce electricity with the

smallest deviation. The mechanism for calculating investment risk from the standard

deviation was carried out by comparing the three fuels used to produce electrical energy,

namely, palm fronds, empty fruit bunch, and oil palm trunks.

Table 17 shows a comparison of the three types of fuel used to generate electricity.

Fuel derived from oil palm waste was categorized based on the type of waste tested

through mechanization so that it was able to generate electricity from renewable energy

fuel. The results of the analysis show that the type of fuel from the palm fronds had the

lowest standard deviation value and the rupiah value of the frond waste was cheaper

than other types of oil palm waste. The results of these calculations show that the small-

est risk for producing electricity comes from EBT fuel, which comes from the type of

palm frond waste at a price of 0.0259 USD/Kg and was able to generate electricity worth

0.0259 USD/kWh.

Table 17. Standard deviation analysis.

No Production Cost Oil Palm

Frond

Empty Fruit

Bunch

Oil Palm

Trunk

1 Biomass feedstock (USD/kg) 0.0259 0.0275 0.0254

2 Biodiesel (USD/L) 0.3107 0.3107 0.3107

3 System utility (USD/kWh) 0.0558 0.0558 0.0558

4 Staff and operator salary (USD/kWh) 0.0456 0.0456 0.0456

5 Maintenance (USD/kWh) 0.0003 0.0003 0.0003

6 Yearly capital cost (USD/kWh) 0.0099 0.0099 0.0099

7 Total 0.4483 0.4498 0.4478

8 Electric production (KW/day) 839 865 784

9 Feedstock consumption (kg/h) 49.55 51.06 46.33

10 Standard deviation (SD) 2.758 2.773 2.763

11 Electric price (Rp/kWh) 0.0259 0.0275 0.0254

3.7. Socio-Environment Impact Analysis

Inside the Industrial Revolutions 4.0 era, access to electricity is one of the primary

needs of everyday life both in urban and rural areas. The implementation of power

plants, especially in rural areas, has the aim of improving the socio-economic life of the

community. Social influence is expected to be felt in the long term, such as the ability to

read, study, and obtain information, and the addition of skills so that it can open oppor-

tunities for people to be more creative and innovative in developing their ability to face

the vicious cycle of poverty.

Positive influences from an economic perspective can increase people’s income and

create many new businesses. Socio-cultural changes are marked by changes in lifestyle

that are widely adopted from television shows, including in terms of daily lifestyle. Other

changes include an increase in school performance and better health and awareness in

protecting the environment and safety. The negative influence that must be watched is

the fading of local cultural values, such as cooperation, and consumer culture, seen from

the adoption of television shows and other media.

Before the gasification power plant was implemented, the majority of the village

community’s work was as farmers and farm laborers, whereas after the power plant,

many residents left their jobs in the agricultural sector. They turned to the productive

sector that uses electricity as an energy source to produce products. The economy, which

had previously relied on agriculture, then relied on services and industry. The presence

of power plants was proven to recruit labor so that unemployment was reduced. One

factor was the new employment opportunities presented for residents. The employment


opportunities included food and beverage, document services, boarding, and rented

houses, lodging, and other service sectors.

The community around the power plant area was directed to obtain additional in-

come apart from agricultural products. The electricity provided by gasification power

plants has a positive impact on the community’s economy. The community has new

business opportunities including in the fisheries and trade sectors. If this gasification

power plant was built in a coastal area that has biomass potential, the community was

also facilitated by making boreholes so that sufficient water was available, and the es-

tablishment of a fish auction place.

Viewed from an environmental aspect, the implementation of power plants will

have an impact on the environment, starting from the construction process to the opera-

tion. Impacts that occur are possibly both temporary and permanent. The construction of

power plants involves the use of land or space inside or on the surface of the land, the use

of water resources, and the most influential environment was the presence of pollution to

the air and water. The indicators and parameters of the environmental quality index can

be seen in Table 18.

Table 18. Indicators and Parameters of the Environmental Quality Index in 2019 [49].

No. Indicators Parameters Weight

1. River water

quality

TSS

30%

DO

BOD

COD

Total Phosphate

Fecal Coliform

Total Coliform

2. Air quality SO2

30% NO2

3. Quality of

land

cover area of forest cover, shrubs and swamp shrubs lo-

cates in forest areas and protected function areas (river

borders, lakes and beaches, slopes > 25%) green open

spaces, botanical gardens and biodiversity parks

40%

The construction of a power plant that utilizes green land will disrupt vegetation

and also affect the wildlife that exists in the environment. Flue gas produced from the

combustion of diesel engines will cause an increase in air temperature around the power

plant, in addition to the combustion product in the form of CO2 , which causes pollution

or contributes to the emission of greenhouse gases. Water used as a syngas cooler before

it is used on a diesel engine will reduce the water supply around the plant, both for sur-

face and underground water. After the water is used, it becomes wastewater and needs to

be disposed of in the environment. With wastewater disposal, the temperature of the

waste will be higher than the average temperature, and the most dangerous impact is the

pollutants contained in the water, which can cause environmental damage. Therefore,

before wastewater is discharged, it is necessary to treat it first. In addition to liquid waste,

solid waste in the form of ash from gasification is also produced from power plants. The

handling of solid waste must be managed so that it does not have a negative impact.

Furthermore, the level of noise and vibration around the project site will increase; during

plant operations this condition also continues to occur.

4. Conclusions

The Prototype of Gasification with multi-stage downdraft gasifier technology with a

capacity of 10 kW has been developed on a laboratory scale. Furthermore, the result was




between.


changed to citation number 49


technically and economically feasible as a commercial alternative power plant on a small

scale of 100 kW. The economic analysis indicated that the power plant will have an NPV

of USD 48,846 with an IRR of 9.72%. The payback period was achieved at six years for the

required investment costs of USD 56,143. The availability of fuel i.e., oil palm plantation

waste in the form of oil palm frond and oil palm trunk was sufficient throughout the year

so that it can continue to be used as long as the price was no more than USD 0.026/kg, as

well as diesel fuel with a maximum price of USD 0.47/L. All investment costs can be re-

turned following the payback period if the plant can operate at least 355 days/year. Risk

analysis was also carried out by considering the uncertainty of economic conditions that

can affect changes in capital cost, operation and maintenance costs, and increases or de-

creases in revenue. The result, with a probability of 90%, NPV obtained USD 41.833–5.861

with a percentage of 49.94% above the base case was achieved. Meanwhile, IRR was ob-

tained between 8.40% and 11.04%.

In terms of social aspects, the existence of power plant in rural areas was considered

to increase people’s income and create many new businesses. The existence of a power

plant employs the surrounding community. The continuous supply of electrical energy

opens up business opportunities, both micro and medium, that utilize electrical energy as

the primary energy sources. However, adverse environmental impacts must not be ig-

nored from the construction stage to the operation of the power plant. The construction

of power plants must refer to rules that have been issued by the government in order to

maintain an environmental balance.

Author Contributions: Conceptualization, A.R.S. and J.A.P.; methodology, J.I.; software, A.R.S.;

validation, J.I., B.S. and J.A.P.; data curation, E.N.J.; writing—original draft preparation, A.R.S.;

writing—review and editing, J.A.P.; visualization, A.R.S.; supervision, B.S.; funding acquisition, J.I.

All authors have read and agreed to the published version of the manuscript.

Funding: This research received no external funding.

Institutional Review Board Statement: Not applicable

Informed Consent Statement: Not applicable

Data Availability Statement: The data used in this paper were provided by the experimental data

from The Combustion and Energy System Laboratory, Institut Teknologi Sepuluh Nopember

Acknowledgments: Publishing fees were supported by Tidar University from Publication Incen-

tive Program. Thanks to Tidar University for supporting the publication.

Conflicts of Interest: The authors declare no conflict of interest.

Abbreviations

ASTM American Society for Testing and Material

B/C Benefit to Cost Ratio

ER Equivalent Ratio

AR Air Ratio

IDR Indonesian Rupiah

IRR Internal Rate of Return

IRENA International Renewable Energy Agency

LHV Low Heating Value

LCOE Leverage Cost of Electricity

NPV Net Present Value

POME Palm Oil Milk Effluent

O&M Operation and Maintenance

PBP Payback Period

Nomenclature

N Number of period (year)


y Year

Cy Cash inflow in year (USD)

i Interest rate (%)

S Standard Deviation

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Comment [ARS35]: I has been

added this catition based on

previous revision, I think the

problem starting from this

point

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Article

Micro-Grid Oil Palm Plantation Waste Gasification Power

Plant in Indonesia: Techno-Economic and




50275 Semarang, Indonesia 2 Department of Mechanical Engineering, Faculty of Engineering, Institut Teknologi Sepuluh Nopember,



[email protected] 5 Department of Mechanical Engineering, Faculty of Engineering, Universitas Tidar, 56116 Magelang, Indone-

sia





that are converted with multi-stage downdraft gasification technology. This study aimed to conduct

a technical analysis, economic analysis, investment risk analysis, social analysis, and an environ-

mental impact assessment of power plants fueled by oil palm plantation waste. The method used

was the upscaling of a prototype of a 10 kW power plant to 100 kW. The results showed that it was

technically and economically feasible to apply. The economic indicators were a positive NPV of

USD 48.846 with an IRR of 9.72% and a B/C ratio of 1.16. The risk analysis predicted a probability



growth of new economic sectors that utilize electricity as a primary source. An analysis of the envi-

ronmental effects is critical so that the impacts can be minimized. Overall, the construction of small-

scale power plants in oil palm plantations is worth considering as long as it is carried out following

the applicable regulations.


1. Introduction




installed capacity of 5500 MWe as shown in Figure 1. Until 2018, the percentage of renew-

able energy utilization reached 6.2%. The bioenergy sector is expected to contribute 8.2%

to national energy, one way of which is through the development of bioenergy power

plants [1]. The utilization of new and renewable energy has become a topic of interest and

is on the agenda in the world as one of the solutions to overcome the problems of the

current energy crisis. The cause of this energy crisis is the decreasing availability of fossil

fuels. Biomass, because of its abundant availability, can substitute for the use of fossil

fuels. Compared to other renewable energy sources (wind, solar, etc.), energy production









Academic Editor(s):



Published: date



claims in published maps and institu-

tional affiliations.



publication under the terms and con-

ditions of the Creative Commons At-

tribution (CC BY) license (https://cre-

ativecommons.org/licenses/by/4.0/).


from biomass requires lower capital investment costs [2]. To encourage the acceleration

of the use of renewable energy in Indonesia, the government has established various pol-

icies. The government has the target of an additional installed capacity from renewable

energy power plants of 905.73 megawatts (MW), consisting of 196 MW from geothermal

powerplants, 557.93 MW from hydro power plants, 138.8 MW from solar power plants,

and 13 MW from bio power plants. Meanwhile, the renewable energy investment target

in 2021 will increase to USD 2.05 billion or approximately IDR 28.9 trillion (assuming an

exchange rate of IDR 14,100 per dollar) from the investment achievement in 2020, which

amounted to USD 1.36 billion or approximately IDR 19.2 trillion. Some of the govern-

ment’s policies on new energy are as follows [3]:

a. Implementation of the mandatory B30 program for all sectors, followed by the devel-

opment of biodiesel trials as a substitute for fossil diesel with B100 (biodiesel 100%)

development technology;


procure bioethanol-type biofuel, in accordance with the Regulation of the Minister of

Energy and Mineral Resources Number 12 of 2015;





of the Minister of Energy and Mineral Resources Regulation Number 49 of 2018 con-

cerning the Use of Rooftop Solar Power Generation Systems by state power plant

consumers;









MW has been developed [4]. Development of bioenergy-based power plants (on-grid) un-

til 2013 reached 90.5 MW, while for those off-grid it reached 1626 MW [5]. One of the most

significant biomass potentials in Indonesia is from solid waste from oil palm plantations.

Oil palm plantations in Indonesia are the largest source of biomass with a total electricity

energy that can be generated of 5495 MWe [6]. The sources come from plantation wastes

(oil palm fronds and oil palm trunks) or waste from oil palm mill production (meso scrap

28%

23%28%

21%



fiber, palm kernel shell, and oil palm mill effluent). However, not all these wastes are

utilized as energy, so they have the potential to become sources of greenhouse gas emis-

sions when they decompose. In addition, in terms of the environment in recent years, the

oil palm plantation industry in Indonesia has been in the European Union’s and the

United States’ spotlight because it is considered an industry that is not environmentally

friendly due to the impact it causes [7]. If the renewable energy target policy is imple-

mented by 2030, it is expected to reduce greenhouse gas emissions by 29% compared to

2010.














the issue of land acquisition is a significant factor in the lack of access to electricity in rural

communities located in oil palm plantations.









present, oil palm fronds are usually burned as fuel in processing plants, and the remainder

is disposed of in plantations, while oil palm trunks after the replanting process are not

utilized [10]. Utilization of oil palm waste as a raw material for renewable energy that can

generate electricity is a solution to the residue of oil palm industry activities in Indonesia.

According to the Ministry of Energy and Mineral Resources of the Republic of Indonesia,


the renewable energy market in Indonesia is not yet optimal because it relies on solar

panels which have components that are imported. Thus, the government is pushing a

draft Indonesian Presidential Regulation that will regulate the price of new renewable

electricity. Through this policy, it is hoped that the production of renewable energy that

utilizes oil palm waste as a raw material can grow in oil palm industrial areas in Indonesia.

In addition, the push for the use of renewable energy is in line with the global commitment

to the 7th point of the Sustainable Development Goals that are to be achieved by 2030

regarding clean and affordable energy.








thetic gas (syngas), consists of combustible syngas (i.e., CO, H2, and CH4) and non-com-

bustible gas (i.e., CO2, N2, and the remaining O2) [14]. Gasification reactions occur in a

reactor called a gasifier. There are various types of gasifiers such as updraft, downdraft,

cross draft, bubbling fluidized bed gasifiers, and circulating fluidized beds (CFBs) [15].

One type of gasifier that is widely used is the downdraft [16–18]. A downdraft gasifier has

the advantage of a high carbon conversion rate, low tar production, and simple construc-

tion compared to other types [19].




tion wastes used were oil palm fronds and oil palm trunks. Both of these plantation wastes

have been reported by several previous studies and are suitable as feedstock for gasifica-

tion. The power plant analyzed was upscaled from a laboratory-scale prototype with a

capacity of 10 kW, which has been reported in previous studies, to a small-scale power

plant with a capacity of 100 kW. The gasification technology used the multi-stage

downdraft gasifier [20]. This technology has the advantage of being able to produce syn-

gas with a high–low heating value and a low tar content of 2.6 times compared to the


multi-stage gasification technology was also equipped with an air heating system that was

also capable of producing low tar content up to 27.8 mg/Nm3 and temperature increases

at the partial oxidation zone with a constant equivalent ratio [18].



in gas generators. Modification of the gas generator was conducted by adjusting the sup-

ply of oxidizer (air supply) into the reaction zone. A downdraft-type gasification power

plant with a capacity of 25 kW was also developed by ENTRAGE Energies System AG,

using a 4.3 L six-cylinder petrol engine coupled to an electric generator. A downdraft-type

gasification power plant was also developed by ALL POWER LABS with a power output

of 15 kW [21,22]. The gasifier was coupled to a four-cylinder diesel engine and an electric

generator. Currently, one of the largest biomass power plants is located in the UK, near

Cheshire, and it produces 21.5 MW of electrical energy. A gasification power plant with a

capacity of 100 kW in current market conditions is more profitable than a larger capacity

provided that the fuel used is not difficult to supply [23]. Situmorang [24] reports that

gasification power plants can be used to utilize locally available biomass as fuel with a

generating capacity of less than 200 kW.



as the risk variables that could hinder the success of the project. Some analyses that needed

to be conducted were techno-economic, risk, and social–environmental. Techno-economic


analyses of gasification power plants have been carried out in several previous studies.

Porcu [25] conducted a techno-economic analysis of a gasification power plant being up-

scaled from 500 to 200 kW using a bubbling fluidized bed gasifier. Singh conducted a

techno-economic analysis of hybrid power plants between gasification, solar PV, and fuel

cells, but the gasification technology used was not mentioned. Economic and environmen-

tal impact analyses of an 11 MW capacity gasification power plant were carried out by

Cardoso [23], and the results of the study reported that the NPV was influenced by reve-

nue from electric sales. Sobamowo [26]conducted a techno-economic analysis of a gasifi-

cation power plant using downdraft gasification technology with a capacity of 60 MW;

the results of the study reported that the distance between the power plant and the source

of raw materials affected the raw material costs. Moreover, local materials for capital in-

vestment, maintenance, and fuel costs provided higher profit margins.

Emiliano [27,28] conducted a techno-economic assessment of power plants with gas-

ification technology. The results of the study reported that the price of gaseous fuel (i.e.,

natural gas) dramatically affects the economics of the power plant project. In addition,

power efficiency and the selling price of electricity can produce a higher NPV. Cali [29]

conducted a techno-economic analysis of the FOAK industrial gasification plant. The re-

sults of the study reported that the cost of fuel dramatically affects the cost of electricity

(COE), and the economic results can be increased by technical development to reduce op-

erating costs. Kivumbi [30] conducted a techno-economic analysis of a gasification power

plant with a capacity of 425 kW using municipal solid waste as fuel. The results of the

study reported that for small-scale power plants, a high interest rate causes the return on

investment to be longer, so it is not appropriate. In addition, the distance between the

source of raw materials and power plants affects the total cost of transportation to increase

the cost of electricity production. Gokalp [31] conducted a techno-economic analysis of a

gas tire scrap power plant capacity of 5 MWe. The gasification technology used was a

circulating fluidized bed. The results of the study reported that the price of raw materials

dramatically influences the financial result, but if it cannot be reduced, the efficiency of

the gasification system needs to be increased. Based on the results of the published techno-

economic analyses, various variables affect the financial results of a gasification power

plant and are different for each region, the type of raw material used, and the planned

generating capacity. Moreover, most publications only discuss the economic analysis, and

only a few discuss investment, social, and environmental risk analyses simultaneously,

while these are interrelated. The generating capacity analyzed was also medium- to large-

scale, while for the microscale, the literature is still limited.






was calculated as the net present value (NPV), internal rate of return (IRR), benefit-to-cost

ratio (B/C), and payback period (PBP). The investment risk was also analyzed using the

Monte Carlo method. Furthermore, the final analysis carried out was an analysis of the

social and environmental impacts due to the gasification power plant.





The aim was to obtain the difference between the non-profit models on the prototype scale

and a profitable model on a commercial scale. The results of the pilot-scale experiment

were used as a reference for modeling the performance of microscale gasification power

plants. The technical aspects discussed in this study are feedstock characterizations using

ultimate and proximate analyses, explanations of experimental activities, and analysis of


economic models. Techno-economic analyses were carried out including investment costs

and operating costs. Meanwhile, for the technical analysis, the size of the biomass power

plant was upscaled. Furthermore, an income analysis was carried out based on financial

assumptions. After the technical aspects were defined, the next step was to perform an

economic analysis and socio-environmental analysis. The Monte Carlo method was used

for the risk analysis with Crystal Ball software Version 11.1.2.4® .





a higher heating value. The multi-stage gasification technology was developed in the com-

bustion laboratory and an energy system from the Sepuluh Nopember Institute of Tech-

nology. The scheme of the gasification system is shown in Figure 3.


The solid fuel consumption of this reactor was 8 kg/h. Before entering the reactor, the

fuel was placed inside a hopper equipped with a screw conveyor. The amount of fuel


was ambient air, and before entering the gasifier, it was preheated until 200 °C. In addition

to obtaining external heating, the air was also internally heated inside the gasifier by plac-

ing an air ring in the form of a pipe that circled the inner wall of the reactor. In the first

stage, the air was injected into the pyrolysis zone using six nozzles. The air in this pyrol-

ysis zone initiated the oxidation reaction between the air and carbon, called oxidative py-

rolysis [20,33–36]. The oxidation reaction released heat so that the pyrolysis properties

changed from endothermal to exothermal. This was advantageous because the released

heat from the partial oxidation zone was reduced. The temperature increased in the py-

rolysis zone cracking the tar components from primary to secondary tar [18].










Gasifier walls are built using stainless-steel plates with a thickness of 3 mm. The total

height of the reactor was 1.3 m with a diameter of 0.5 m. The ash sweeping mechanism

was placed above the grate to prevent blockage of the grate hole. The sweeper was moved

every 15 min after syngas under flammable conditions. The ash that fell from the grate

was moved to the box using a screw conveyor with a 45° slope. After that, periodic ash

disposal was carried out every 3 h of operation. Syngas was emitted from the gasifier


to separate heavy particles, such as ash and fine grains, that were carried out by the syn-

gas. Heavy particles were separated due to the fact of gravity, and the syngas was cleaned

using a dry filter. Inside the dry filter there were two layers of filter media: the lowest

layer was activated carbon, and the top layer was wood dust. The tar component carried

in the syngas was captured by the activated carbon. The syngas temperature coming out

of the gasifier was 150 °C and 27 °C after it passed the dry filter. The tar and heavy oil

components contained in the syngas were condensed and absorbed by activated carbon

[39]. The layer of sawdust served as an additional layer to capture the unfiltered tar and

heavy oil in the activated carbon layer. To ensure the filtering efficiency and the final tar

content, the syngas was tested by taking a sampling gas every 30 min of operation. Syngas

was condensed using a condenser with ice water as cooling media. The condensed tar

stuck to the wall of the condenser and moved down and was accommodated with a meas-

uring cup [40]. The gas that was separated from the tar was later stored in a gas sampling

bag and tested separately using gas chromatography.

Furthermore, syngas was channeled to a diesel engine that was connected to a 10 kW

electric generator with dual fuel operating condition (i.e., syngas and diesel fuel). Syngas

entered the diesel engine via the air intake channel through the mixer, and the amount

was regulated using a valve.


The raw materials used were oil palm fronds and oil palm trunks that were shredded

into fibers with lengths of 3–5 cm as shown in Figure 4. Characterization was conducted

by testing the raw material using ultimate and proximate analyses. The test was carried

out at the Energy Institute Laboratory of the Sepuluh Nopember Institute of Technology.

Proximate analysis refers to the ASTM D 5142-04 standard for the parameters of moisture,

volatiles, and ash. Meanwhile, fixed carbon was tested based on the difference between

the total mass reduced by moisture, volatiles, and ash. The ultimate analysis was carried

out according to the ASTM D 5373-02 standard for carbon, hydrogen, oxygen, nitrogen,

and sulfur components. The oxygen was the difference between the total mass minus the

previous component. Analysis of the calorific value was carried out using a bomb calo-

rimeter (AC-350 Bomb Calorimeter) according to the ASTM D4809-18 for analysis of gross

calorific value. Ultimate analysis uses sample sizes between 100 and 300 g to obtain accu-

rate results. Carbon, nitrogen, and sulfur testing in this study used a sample size of 2–3

mg, which had an error tolerance of 0.05 w. (500 ppm) with an uncertainty below 0.02

w.%. Based on the manufacturer’s specification data from the equipment used, the uncer-

tainty of the instrument was in the moderate concentration range of 0.3 w.%. If the sample

had a carbon content higher than 90 w.%, then the tolerance was extended to 0.5 w.%. The

results of the analysis of the feedstock are presented in Table 1.





Proximate

Volatile 85.1 86.7

Moisture 70.6 75.6

Ash 3.37 3.35


Ultimate

Carbon 48.43 51.41


Oxygen 46.75 51.16

Nitrogen 12.40 0.17



The used equivalent ratio (ER) was the optimum ratio from previous studies [20,31] which

was 0.4 while the air ratio (AR) for the pyrolysis zone, partial oxidation, and reduction

were selected at the optimum ratio of 10%, 80%, and 10%. The AR percentage shows the

amount of air entering for each zone, meaning that from the total air based on ER 0.4

divided into three locations, 10% into the pyrolysis zone, 80% into partial oxidation, and

10% into the reduction zone. Syngas was cleaned using a cyclone and dry filter to further

flow into a diesel engine. The experimental data generated from the gasification experi-

ment are shown in Table 2.


Parameter Value









CO 18%

H2 25%

CH4 4%


2.4. Economic Model

The economic analysis in this study was carried out using a 10 kW capacity gasifica-

tion experimental data reference that was upscaled to 100 kW. Some operating conditions

were equated according to the experimental reference data, and the resulting data were

used as input data for the economic analysis. A techno-economic analysis was carried out

for every year of the estimated service life of the gasification system of 20 years. The ref-

erence cost component started from the capital cost to the estimated revenue for each year.

3. Result







The oil palm plantation waste was grouped into two types, namely, waste from plan-

tations in the form of oil palm fronds and trunks and waste from the processing of oil






thousand tons/year in Papua. The total energy that can be generated from all the potential

reaches 5495 Mwe [6]. Palm fronds were chosen because they are always available on






that it is only available during the replanting process, the amount was less if it was divided

within one year. The total potential energy from oil palm trunk reaches 815 MW [6].







that the cost of the transportation of the raw materials could be reduced [23]. Based on the

planned installed capacity, 1189 tons/day of raw materials were needed. Thus, at least 100

hectares of oil palm plantation were required. When compared with the areas of lands in

Sumatra, Kalimantan, Sulawesi, and Papua, this plant can be placed anywhere because

the existing land area was greater than the required minimum land area [41]. The maxi-

mum moisture content of the solid fuel was 40%.



























Civil work 664.31

Building 763.96



















based on the number of operating hours for one year. Details of the cost of electricity needs

for the plant are presented in Table 4.


Item Cost





The cost component of the solid fuel is the cost of collecting, cutting, and transporta-

tion from the source of the solid fuel to the location of the power plant. Oil palm fronds









against diesel was a maximum of 60%. Details of the electricity production costs are pre-

sented in Table 5.


Item Cost










engine was Cummins 6BT5,962, which was coupled with a 100 kVA generator. The tech-

nical specifications can be seen in Table 6.


Engine Cummins 6BT5.9G2


KVA 100

KW 80



Piston disp. 5900 L


Oil capacity 16.4 L

Dimension 2910 × 1110 × 1450 mm












Commented [M1]: Should it be 6BT5.9G2

Commented [M2]: Please confirm if you have got

the copyright to use the table.






















electrical energy output capacity was calculated, and the results obtained are presented in

Table 9. The number of operating days for one year was assumed to be 355 days, with







Frequency 50 Hz





3.3. Revenues


with the price of electricity following the state power plant standard for renewable energy,

which was $0.121/kWh. Electricity consumption costs for the plant reduced gross revenue.

Detailed calculations for the power plant are presented in Table 10.
















Interest rate 8 %

Inflation rate 2 %




conducted economic analysis was the NPV, PBP, and the IRR [44]. The NPV calculation

was conducted by calculating the present value of cash flows for a certain period. The

calculated cash flow was the difference between the benefits and costs for each year the

NPV was determined. The equation to calculate the NPV is shown below [23]:

NPV = ∑ Cy x ((1 + i)y − 1)

i x (1 + i)y− Cy=0 x (1 + i)y

N

y=0

where i is the interest rate, N is the number of periods (years), Cy are number of cash

inflows in year y, and Cy = 0 is the total investment of the first year plus cash outflows.

Interest rates were used to calculate the discount factor and present values for costs and

benefits. The operating period was assumed to be 20 years [25] with an interest rate of 8%.

After calculating, if the NPV was positive, the investment was profitable and vice versa.

Thus, if t was profitable, capital costs could be returned during the operating period.




follows [23]:

IRR = cash flows

(1 + i)y− initial investment cost



each year so that the initial investment costs could be returned. The equation used to cal-

culate the payback period is as follows [23]:

PBP = total investment cost

yearly cash flow





S = √1

N − 1∑ xi − x̅










NPV [25].





shown in Table 12, which means this power plant project provides benefits. The ratio be-

tween cost and benefit was greater than 1, at 1.16. Meanwhile, the internal rate of return

was also above the interest rate of 9.72%, so the investment was still profitable. The cost

of electricity was still below the selling price from the state power plant of USD 0.083/kWh,

where the selling price from the government was USD 0.121/kWh, so there was a differ-

ence of USD 0.037/Kwh as profit.



feature, we could simulate several different values or two decision variables. Interest rates

varied from 7% to 12%. The results of this analysis are presented in Table 12. The NPV

continued to decrease along with the increase in the interest rate, but the value remained

positive. The same trend also occurred in the IRR and B/C ratio. Even though the NPV

was always positive, and the B/C ratio was above 1, the results showed that when the

interest rate was at 10–12%, the IRR was already below the interest rate. Thus, investment

had a percentage return that was greater than the interest rate if the interest rate was lower

or equal to 9%. However, the value of the interest rate was a fluctuating value depending

on the economic conditions of the Indonesian state.


Interest Rate 7% 8% 9% 10% 11% 12%

NPV (USD) 57,096 48,846 41,514 34,975 29,124 23,873

IRR (%) 10.75 9.72 8.71 7.73 6.76 5.80

B/C ratio 1.18 1.16 1.15 1.13 1.12 1.10

LCOE ($0.083/kWh)



Investment costs were also varied to determine the range of investment costs that still

provided benefits. The range of investment costs, according to IRENA was from USD 950

to 1650/kW [42]. If one looks at the comparison of the investment costs in Table 13, in the

range from USD 950 to 1100/kW, it was still profitable because the IRR was above the

interest rate. Meanwhile, above USD 1100/kW, it was no longer profitable because the IRR

was under the base interest rate. In this study, the investment cost, which was the base

case, was USD 950/kWh.


Investment Cost

(USD/kWh) 950 1100 1250 1400 1550 1650

NPV (USD) 48,846 44,681 40,515 36,350 32,184 29,407

B/C ratio 1.16 1.15 1.13 1.12 1.10 1.09

IRR (%) 9.72 8.64 7.62 6.67 5.76 5.18

The solid fuel that used for gasification was oil palm frond and oil palm trunk. When

compared for the two fuels, as shown in Table 14, oil palm trunk resulted in a higher NPV

and IRR, which means that it was profitable to use oil palm trunk as fuel. The cost for oil

palm trunk was $0.025/kg, while oil palm frond was $0.026/kg. The difference was because

the oil palm frond requires additional harvesting costs for each period while the palm

trunk does not. However, the use of oil palm frond and oil palm trunk is still profitable.

The difference is only in the profit margin. However, the price for diesel fuel was a maxi-

mum at $0.47/L or the price of subsidies from the government, so that IRR was above 8%.








profitable, as long as the maximum price of diesel fuel is $0.47/L, with a maximum interest

-9

-4

1

6

11

16

21

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

Cas

hfl

ow

(K

US

D)



rate of 9%. This power plant was calculated to implement small villages with low to me-

dium economic levels, and electricity was not used for extensive commercial activities.

Thus, it was possible to use diesel fuel at a subsidized price as long as the price was no

more than the maximum price above. If the price and interest rate were to exceed, the IRR

value was under the base case of interest rate. The existence of subsidies from the govern-

ment is very influential on the benefits to be obtained from a power plant project. In ad-

dition, the subsidy policy can also attract investors to make investments [8,42,44].



Interest rate

7% 13.60 10.75 7.80 4.72 1.41

8% 12.55 9.72 6.80 3.75 0.47

9% 11.52 8.71 5.82 2.80 (0.45)

10% 10.50 7.73 4.86 1.86 (1.36)

11% 9.51 6.76 3.92 0.94 (2.25)

12% 8.53 5.80 2.99 0.04 (3.12)


results are presented in Table 16. The simulation results of the feed-in tariff was below the

base case of USD 0.12/kWh, the IRR was under the base case of interest rate. Thus, if there

was a decrease in feed-in tariffs from the government under the base case, investment in

power plants does not provide optimal benefits. Based on the pattern of increasing feed

tariffs in Indonesia to date, it always increases over a specified period. Thus, the feed-in

tariff can be assumed not to reduce return of investment period because the value contin-

ues to increase. However, decreases were still possible depending on changes in subsidies

and political decisions.


Feed in Tariff

(USD/kWh) 0.102 1.110 0.117 0.124 0.131

NPV (USD) (4581) 16,371 37,323 58,275 79,227

B/C Ratio 0.98 1.05 1.13 1.20 1.27

IRR (%) (1.04) 3.48 7.57 11.44 15.18


Financial risk assessment was carried out to evaluate the effect of economic parame-

ters on investment risk. The risk analysis of the power plant project was carried out using

Crystal Ball software® . This software was chosen because of the ease of operation, and it

is compatible with MS Excel® [45]. Another advantage, was that various types of data dis-

tribution can be chosen according to needs. The simulation was conducted with 1,000,000

iterations. The Monte Carlo method was used for the risk analysis as it calculates with the

technique of statistical sampling, operates with random input components, and has un-

certainty [25]. The input variable was simulated with several iterations and produced sev-

eral data in the form of probabilities. The normal probability distribution was used. The

selection of a probability distribution model in the Monte Carlo analysis was essential

because it affects the accuracy of the simulation results [44,47,48]. In addition, the number

of iterations must also be adjusted to obtain convergence. With a greater number of itera-

tions, the mean and standard deviation will be evenly distributed.















analysis, the probability of investment risk was relatively small because the NPV was al-

ways positive, and the IRR had the higher base case interest rate. Besides, with a 50%







Based on the risk analysis of components that affect NPV, 68% of the most significant

influence was investment cost, while capital cost and revenue were the remainders. Thus,

if the investor can control and reduce investment costs, then it was possible to obtain

higher profits. The investment component that was possible to be reduced was the capital

cost of the gasification system. The investment cost was 74.4%, as shown in Figure 9. The

gasification system used was foreign-made or made with imported products. Considering

the pilot-scale development experience that has been done, it was possible to produce

gasification systems independently so that investment costs can be reduced.



with low risk, standard deviation analysis was used. The analysis can provide information


in the form of the types of raw materials used to produce electricity with the smallest

deviation. The mechanism for calculating investment risk from the standard deviation

was carried out by comparing the three fuels used to produce electrical energy, namely,

palm fronds, empty fruit bunch, and oil palm trunks.





lowest standard deviation value and the rupiah value of the frond waste was cheaper than

other types of oil palm waste. The results of these calculations show that the smallest risk

for producing electricity comes from EBT fuel, which comes from the type of palm frond

waste at a price of 0.0259 USD/Kg and was able to generate electricity worth 0.0259

USD/kWh.



Frond

Empty Fruit

Bunch

Oil Palm

Trunk


2 Biodiesel (USD/L) 0.3107 0.3107 0.3107





7 Total 0.4483 0.4498 0.4478







needs of everyday life both in urban and rural areas. The implementation of power plants,

especially in rural areas, has the aim of improving the socio-economic life of the commu-

nity. Social influence is expected to be felt in the long term, such as the ability to read,

study, and obtain information, and the addition of skills so that it can open opportunities

for people to be more creative and innovative in developing their ability to face the vicious

cycle of poverty.




















plants has a positive impact on the community’s economy. The community has new busi-

ness opportunities including in the fisheries and trade sectors. If this gasification power

plant was built in a coastal area that has biomass potential, the community was also facil-

itated by making boreholes so that sufficient water was available, and the establishment

of a fish auction place.

Viewed from an environmental aspect, the implementation of power plants will have

an impact on the environment, starting from the construction process to the operation.

Impacts that occur are possibly both temporary and permanent. The construction of







1. River water

quality

TSS

30%

DO

BOD

COD

Total Phosphate

Fecal Coliform

Total Coliform

2. Air quality SO2

30% NO2

3. Quality of

land





40%

The construction of a power plant that utilizes green land will disrupt vegetation and

also affect the wildlife that exists in the environment. Flue gas produced from the com-

bustion of diesel engines will cause an increase in air temperature around the power plant,

in addition to the combustion product in the form of CO2 , which causes pollution or con-

tributes to the emission of greenhouse gases. Water used as a syngas cooler before it is

used on a diesel engine will reduce the water supply around the plant, both for surface

and underground water. After the water is used, it becomes wastewater and needs to be

disposed of in the environment. With wastewater disposal, the temperature of the waste

will be higher than the average temperature, and the most dangerous impact is the pollu-

tants contained in the water, which can cause environmental damage. Therefore, before

wastewater is discharged, it is necessary to treat it first. In addition to liquid waste, solid

waste in the form of ash from gasification is also produced from power plants. The han-

dling of solid waste must be managed so that it does not have a negative impact. Further-

more, the level of noise and vibration around the project site will increase; during plant

operations this condition also continues to occur.

4. Conclusions



Commented [M3]: Please confirm if you have got

the copyright to use the table.
























validation, J.I., B.S. and J.A.P.; data curation, E.N.J.; writing—original draft preparation, A.R.S.; writ-

ing—review and editing, J.A.P.; visualization, A.R.S.; supervision, B.S.; funding acquisition, J.I. All

authors have read and agreed to the published version of the manuscript.





from The Combustion and Energy System Laboratory, Institut Teknologi Sepuluh Nopember


Abbreviations



ER Equivalent Ratio

AR Air Ratio









PBP Payback Period

Nomenclature


y Year



i Interest rate (%)


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Commented [M4]: Please note that ref 28 and ref

29 are the same, please revise. If you have to

delete one of them, please also revise the refs

order in the main text.


Article

Micro-Grid Oil Palm Plantation Waste Gasification Power Plant

in Indonesia: Techno-Economic and




50275 Semarang, Indonesia 2 Department of Mechanical Engineering, Faculty of Engineering, Institut Teknologi Sepuluh Nopember,



[email protected] 5 Department of Mechanical Engineering, Faculty of Engineering, Universitas Tidar, 56116 Magelang, Indo-

nesia





that are converted with multi-stage downdraft gasification technology. This study aimed to con-

duct a technical analysis, economic analysis, investment risk analysis, social analysis, and an en-

vironmental impact assessment of power plants fueled by oil palm plantation waste. The method

used was the upscaling of a prototype of a 10 kW power plant to 100 kW. The results showed that it

was technically and economically feasible to apply. The economic indicators were a positive NPV

of USD 48.846 with an IRR of 9.72% and a B/C ratio of 1.16. The risk analysis predicted a probability



growth of new economic sectors that utilize electricity as a primary source. An analysis of the en-

vironmental effects is critical so that the impacts can be minimized. Overall, the construction of

small-scale power plants in oil palm plantations is worth considering as long as it is carried out

following the applicable regulations.


1. Introduction




installed capacity of 5500 MWe as shown in Figure 1. Until 2018, the percentage of re-

newable energy utilization reached 6.2%. The bioenergy sector is expected to contribute

8.2% to national energy, one way of which is through the development of bioenergy

power plants [1]. The utilization of new and renewable energy has become a topic of

interest and is on the agenda in the world as one of the solutions to overcome the prob-

lems of the current energy crisis. The cause of this energy crisis is the decreasing availa-

bility of fossil fuels. Biomass, because of its abundant availability, can substitute for the

use of fossil fuels. Compared to other renewable energy sources (wind, solar, etc.), en-









Academic Editor(s):



Published: date



claims in published maps and insti-

tutional affiliations.



publication under the terms and

conditions of the Creative Commons

Attribution (CC BY) license

(https://creativecommons.org/license

s/by/4.0/).


ergy production from biomass requires lower capital investment costs [2]. To encourage

the acceleration of the use of renewable energy in Indonesia, the government has estab-

lished various policies. The government has the target of an additional installed capacity

from renewable energy power plants of 905.73 megawatts (MW), consisting of 196 MW

from geothermal powerplants, 557.93 MW from hydro power plants, 138.8 MW from

solar power plants, and 13 MW from bio power plants. Meanwhile, the renewable energy

investment target in 2021 will increase to USD 2.05 billion or approximately IDR 28.9

trillion (assuming an exchange rate of IDR 14,100 per dollar) from the investment

achievement in 2020, which amounted to USD 1.36 billion or approximately IDR 19.2

trillion. Some of the government’s policies on new energy are as follows [3]:

a. Implementation of the mandatory B30 program for all sectors, followed by the de-

velopment of biodiesel trials as a substitute for fossil diesel with B100 (biodiesel

100%) development technology;


procure bioethanol-type biofuel, in accordance with the Regulation of the Minister

of Energy and Mineral Resources Number 12 of 2015;





of the Minister of Energy and Mineral Resources Regulation Number 49 of 2018

concerning the Use of Rooftop Solar Power Generation Systems by state power plant

consumers;









MW has been developed [4]. Development of bioenergy-based power plants (on-grid)

until 2013 reached 90.5 MW, while for those off-grid it reached 1626 MW [5]. One of the

most significant biomass potentials in Indonesia is from solid waste from oil palm plan-

tations. Oil palm plantations in Indonesia are the largest source of biomass with a total

electricity energy that can be generated of 5495 MWe [6]. The sources come from planta-

tion wastes (oil palm fronds and oil palm trunks) or waste from oil palm mill production

28%

23% 28%

21%



(meso scrap fiber, palm kernel shell, and oil palm mill effluent). However, not all these

wastes are utilized as energy, so they have the potential to become sources of greenhouse

gas emissions when they decompose. In addition, in terms of the environment in recent

years, the oil palm plantation industry in Indonesia has been in the European Union’s

and the United States’ spotlight because it is considered an industry that is not environ-

mentally friendly due to the impact it causes [7]. If the renewable energy target policy is

implemented by 2030, it is expected to reduce greenhouse gas emissions by 29% com-

pared to 2010.














the issue of land acquisition is a significant factor in the lack of access to electricity in

rural communities located in oil palm plantations.









present, oil palm fronds are usually burned as fuel in processing plants, and the re-

mainder is disposed of in plantations, while oil palm trunks after the replanting process

are not utilized [10]. Utilization of oil palm waste as a raw material for renewable energy

that can generate electricity is a solution to the residue of oil palm industry activities in

Indonesia. According to the Ministry of Energy and Mineral Resources of the Republic of


Indonesia, the renewable energy market in Indonesia is not yet optimal because it relies

on solar panels which have components that are imported. Thus, the government is

pushing a draft Indonesian Presidential Regulation that will regulate the price of new

renewable electricity. Through this policy, it is hoped that the production of renewable

energy that utilizes oil palm waste as a raw material can grow in oil palm industrial areas

in Indonesia. In addition, the push for the use of renewable energy is in line with the

global commitment to the 7th point of the Sustainable Development Goals that are to be

achieved by 2030 regarding clean and affordable energy.








thetic gas (syngas), consists of combustible syngas (i.e., CO, H2, and CH4) and

non-combustible gas (i.e., CO2, N2, and the remaining O2) [14]. Gasification reactions oc-

cur in a reactor called a gasifier. There are various types of gasifiers such as updraft,

downdraft, cross draft, bubbling fluidized bed gasifiers, and circulating fluidized beds

(CFBs) [15]. One type of gasifier that is widely used is the downdraft [16–18]. A

downdraft gasifier has the advantage of a high carbon conversion rate, low tar produc-

tion, and simple construction compared to other types [19].




tion wastes used were oil palm fronds and oil palm trunks. Both of these plantation

wastes have been reported by several previous studies and are suitable as feedstock for

gasification. The power plant analyzed was upscaled from a laboratory-scale prototype

with a capacity of 10 kW, which has been reported in previous studies, to a small-scale

power plant with a capacity of 100 kW. The gasification technology used the multi-stage

downdraft gasifier [20]. This technology has the advantage of being able to produce

syngas with a high–low heating value and a low tar content of 2.6 times compared to the


multi-stage gasification technology was also equipped with an air heating system that

was also capable of producing low tar content up to 27.8 mg/Nm3 and temperature in-

creases at the partial oxidation zone with a constant equivalent ratio [18].



in gas generators. Modification of the gas generator was conducted by adjusting the

supply of oxidizer (air supply) into the reaction zone. A downdraft-type gasification

power plant with a capacity of 25 kW was also developed by ENTRAGE Energies System

AG, using a 4.3 L six-cylinder petrol engine coupled to an electric generator. A

downdraft-type gasification power plant was also developed by ALL POWER LABS with

a power output of 15 kW [21,22]. The gasifier was coupled to a four-cylinder diesel en-

gine and an electric generator. Currently, one of the largest biomass power plants is lo-

cated in the UK, near Cheshire, and it produces 21.5 MW of electrical energy. A gasifica-

tion power plant with a capacity of 100 kW in current market conditions is more profita-

ble than a larger capacity provided that the fuel used is not difficult to supply [23]. Si-

tumorang [24] reports that gasification power plants can be used to utilize locally avail-

able biomass as fuel with a generating capacity of less than 200 kW.



as the risk variables that could hinder the success of the project. Some analyses that

needed to be conducted were techno-economic, risk, and social–environmental. Tech-


no-economic analyses of gasification power plants have been carried out in several pre-

vious studies. Porcu [25] conducted a techno-economic analysis of a gasification power

plant being upscaled from 500 to 200 kW using a bubbling fluidized bed gasifier. Singh

conducted a techno-economic analysis of hybrid power plants between gasification, solar

PV, and fuel cells, but the gasification technology used was not mentioned. Economic

and environmental impact analyses of an 11 MW capacity gasification power plant were

carried out by Cardoso [23], and the results of the study reported that the NPV was in-

fluenced by revenue from electric sales. Sobamowo [26]conducted a techno-economic

analysis of a gasification power plant using downdraft gasification technology with a

capacity of 60 MW; the results of the study reported that the distance between the power

plant and the source of raw materials affected the raw material costs. Moreover, local

materials for capital investment, maintenance, and fuel costs provided higher profit

margins.

Emiliano [27] conducted a techno-economic assessment of power plants with gasi-

fication technology. The results of the study reported that the price of gaseous fuel (i.e.,

natural gas) dramatically affects the economics of the power plant project. In addition,

power efficiency and the selling price of electricity can produce a higher NPV. Cali [28]

conducted a techno-economic analysis of the FOAK industrial gasification plant. The

results of the study reported that the cost of fuel dramatically affects the cost of electricity

(COE), and the economic results can be increased by technical development to reduce

operating costs. Kivumbi [29] conducted a techno-economic analysis of a gasification

power plant with a capacity of 425 kW using municipal solid waste as fuel. The results of

the study reported that for small-scale power plants, a high interest rate causes the return

on investment to be longer, so it is not appropriate. In addition, the distance between the

source of raw materials and power plants affects the total cost of transportation to in-

crease the cost of electricity production. Gokalp [30] conducted a techno-economic anal-

ysis of a gas tire scrap power plant capacity of 5 MWe. The gasification technology used

was a circulating fluidized bed. The results of the study reported that the price of raw

materials dramatically influences the financial result, but if it cannot be reduced, the ef-

ficiency of the gasification system needs to be increased. Based on the results of the pub-

lished techno-economic analyses, various variables affect the financial results of a gasi-

fication power plant and are different for each region, the type of raw material used, and

the planned generating capacity. Moreover, most publications only discuss the economic

analysis, and only a few discuss investment, social, and environmental risk analyses

simultaneously, while these are interrelated. The generating capacity analyzed was also

medium- to large-scale, while for the microscale, the literature is still limited.






was calculated as the net present value (NPV), internal rate of return (IRR), bene-

fit-to-cost ratio (B/C), and payback period (PBP). The investment risk was also analyzed

using the Monte Carlo method. Furthermore, the final analysis carried out was an anal-

ysis of the social and environmental impacts due to the gasification power plant.





The aim was to obtain the difference between the non-profit models on the prototype

scale and a profitable model on a commercial scale. The results of the pilot-scale experi-

ment were used as a reference for modeling the performance of microscale gasification

power plants. The technical aspects discussed in this study are feedstock characteriza-


tions using ultimate and proximate analyses, explanations of experimental activities, and

analysis of economic models. Techno-economic analyses were carried out including in-

vestment costs and operating costs. Meanwhile, for the technical analysis, the size of the

biomass power plant was upscaled. Furthermore, an income analysis was carried out

based on financial assumptions. After the technical aspects were defined, the next step

was to perform an economic analysis and socio-environmental analysis. The Monte Carlo

method was used for the risk analysis with Crystal Ball software Version 11.1.2.4®.





a higher heating value. The multi-stage gasification technology was developed in the

combustion laboratory and an energy system from the Sepuluh Nopember Institute of

Technology. The scheme of the gasification system is shown in Figure 3.


The solid fuel consumption of this reactor was 8 kg/h. Before entering the reactor,

the fuel was placed inside a hopper equipped with a screw conveyor. The amount of fuel


was ambient air, and before entering the gasifier, it was preheated until 200 °C. In addi-

tion to obtaining external heating, the air was also internally heated inside the gasifier by

placing an air ring in the form of a pipe that circled the inner wall of the reactor. In the

first stage, the air was injected into the pyrolysis zone using six nozzles. The air in this

pyrolysis zone initiated the oxidation reaction between the air and carbon, called oxida-

tive pyrolysis [20,32–36]. The oxidation reaction released heat so that the pyrolysis

properties changed from endothermal to exothermal. This was advantageous because the

released heat from the partial oxidation zone was reduced. The temperature increased in

the pyrolysis zone cracking the tar components from primary to secondary tar [18].










Gasifier walls are built using stainless-steel plates with a thickness of 3 mm. The to-

tal height of the reactor was 1.3 m with a diameter of 0.5 m. The ash sweeping mechanism

was placed above the grate to prevent blockage of the grate hole. The sweeper was

moved every 15 min after syngas under flammable conditions. The ash that fell from the

grate was moved to the box using a screw conveyor with a 45° slope. After that, periodic

ash disposal was carried out every 3 h of operation. Syngas was emitted from the gasifier


to separate heavy particles, such as ash and fine grains, that were carried out by the

syngas. Heavy particles were separated due to the fact of gravity, and the syngas was

cleaned using a dry filter. Inside the dry filter there were two layers of filter media: the

lowest layer was activated carbon, and the top layer was wood dust. The tar component

carried in the syngas was captured by the activated carbon. The syngas temperature

coming out of the gasifier was 150 °C and 27 °C after it passed the dry filter. The tar and

heavy oil components contained in the syngas were condensed and absorbed by acti-

vated carbon [39]. The layer of sawdust served as an additional layer to capture the un-

filtered tar and heavy oil in the activated carbon layer. To ensure the filtering efficiency

and the final tar content, the syngas was tested by taking a sampling gas every 30 min of

operation. Syngas was condensed using a condenser with ice water as cooling media. The

condensed tar stuck to the wall of the condenser and moved down and was accommo-

dated with a measuring cup [39]. The gas that was separated from the tar was later stored

in a gas sampling bag and tested separately using gas chromatography.

Furthermore, syngas was channeled to a diesel engine that was connected to a 10

kW electric generator with dual fuel operating condition (i.e., syngas and diesel fuel).

Syngas entered the diesel engine via the air intake channel through the mixer, and the

amount was regulated using a valve.


The raw materials used were oil palm fronds and oil palm trunks that were shred-

ded into fibers with lengths of 3–5 cm as shown in Figure 4. Characterization was con-

ducted by testing the raw material using ultimate and proximate analyses. The test was

carried out at the Energy Institute Laboratory of the Sepuluh Nopember Institute of

Technology. Proximate analysis refers to the ASTM D 5142-04 standard for the parame-

ters of moisture, volatiles, and ash. Meanwhile, fixed carbon was tested based on the

difference between the total mass reduced by moisture, volatiles, and ash. The ultimate

analysis was carried out according to the ASTM D 5373-02 standard for carbon, hydro-

gen, oxygen, nitrogen, and sulfur components. The oxygen was the difference between

the total mass minus the previous component. Analysis of the calorific value was carried

out using a bomb calorimeter (AC-350 Bomb Calorimeter) according to the ASTM

D4809-18 for analysis of gross calorific value. Ultimate analysis uses sample sizes be-

tween 100 and 300 g to obtain accurate results. Carbon, nitrogen, and sulfur testing in this

study used a sample size of 2–3 mg, which had an error tolerance of 0.05 w. (500 ppm)

with an uncertainty below 0.02 w.%. Based on the manufacturer’s specification data from

the equipment used, the uncertainty of the instrument was in the moderate concentration

range of 0.3 w.%. If the sample had a carbon content higher than 90 w.%, then the toler-

ance was extended to 0.5 w.%. The results of the analysis of the feedstock are presented in

Table 1.





Proximate

Volatile 85.1 86.7

Moisture 70.6 75.6

Ash 3.37 3.35


Ultimate

Carbon 48.43 51.41


Oxygen 46.75 51.16

Nitrogen 12.40 0.17



The used equivalent ratio (ER) was the optimum ratio from previous studies [20,31]

which was 0.4 while the air ratio (AR) for the pyrolysis zone, partial oxidation, and re-

duction were selected at the optimum ratio of 10%, 80%, and 10%. The AR percentage

shows the amount of air entering for each zone, meaning that from the total air based on

ER 0.4 divided into three locations, 10% into the pyrolysis zone, 80% into partial oxida-

tion, and 10% into the reduction zone. Syngas was cleaned using a cyclone and dry filter

to further flow into a diesel engine. The experimental data generated from the gasifica-

tion experiment are shown in Table 2.


Parameter Value









CO 18%

H2 25%

CH4 4%


2.4. Economic Model

The economic analysis in this study was carried out using a 10 kW capacity gasifi-

cation experimental data reference that was upscaled to 100 kW. Some operating condi-

tions were equated according to the experimental reference data, and the resulting data

were used as input data for the economic analysis. A techno-economic analysis was car-

ried out for every year of the estimated service life of the gasification system of 20 years.

The reference cost component started from the capital cost to the estimated revenue for

each year.

3. Result







The oil palm plantation waste was grouped into two types, namely, waste from

plantations in the form of oil palm fronds and trunks and waste from the processing of oil






thousand tons/year in Papua. The total energy that can be generated from all the poten-

tial reaches 5495 Mwe [6]. Palm fronds were chosen because they are always available on






that it is only available during the replanting process, the amount was less if it was di-

vided within one year. The total potential energy from oil palm trunk reaches 815 MW

[6].







that the cost of the transportation of the raw materials could be reduced [23]. Based on

the planned installed capacity, 1189 tons/day of raw materials were needed. Thus, at least

100 hectares of oil palm plantation were required. When compared with the areas of

lands in Sumatra, Kalimantan, Sulawesi, and Papua, this plant can be placed anywhere

because the existing land area was greater than the required minimum land area [40]. The

maximum moisture content of the solid fuel was 40%.



























Civil work 664.31

Building 763.96



















based on the number of operating hours for one year. Details of the cost of electricity

needs for the plant are presented in Table 4.


Item Cost






The cost component of the solid fuel is the cost of collecting, cutting, and transpor-

tation from the source of the solid fuel to the location of the power plant. Oil palm fronds








against diesel was a maximum of 60%. Details of the electricity production costs are



Item Cost










engine was Cummins 6BT5.9-G2, which was coupled with a 100 kVA generator. The

technical specifications can be seen in Table 6.


Engine Cummins 6BT5.9-G2


KVA 100

KW 80



Piston disp. 5900 L


Oil capacity 16.4 L

Dimension 2910 × 1110 × 1450 mm












Comment [M1]: Should it be

6BT5.9G2

Comment [ARS2]: The code

have been corrected

Comment [M3]: Please confirm

if you have got the copyright to

use the table.

Comment [ARS4]: I confirmed






















electrical energy output capacity was calculated, and the results obtained are presented

in Table 9. The number of operating days for one year was assumed to be 355 days, with







Frequency 50 Hz





3.3. Revenues


with the price of electricity following the state power plant standard for renewable en-

ergy, which was $0.121/kWh. Electricity consumption costs for the plant reduced gross

revenue. Detailed calculations for the power plant are presented in Table 10.
















Interest rate 8 %

Inflation rate 2 %




conducted economic analysis was the NPV, PBP, and the IRR [43]. The NPV calculation

was conducted by calculating the present value of cash flows for a certain period. The

calculated cash flow was the difference between the benefits and costs for each year the

NPV was determined. The equation to calculate the NPV is shown below [23]:

∑ (( ) )

( ) ( )

where i is the interest rate, N is the number of periods (years), Cy are number of cash in-

flows in year y, and Cy = 0 is the total investment of the first year plus cash outflows. In-

terest rates were used to calculate the discount factor and present values for costs and

benefits. The operating period was assumed to be 20 years [25] with an interest rate of

8%. After calculating, if the NPV was positive, the investment was profitable and vice

versa. Thus, if t was profitable, capital costs could be returned during the operating pe-

riod.




follows [23]:

( )



each year so that the initial investment costs could be returned. The equation used to

calculate the payback period is as follows [23]:





√

∑ ̅










NPV [25].





shown in Table 12, which means this power plant project provides benefits. The ratio

between cost and benefit was greater than 1, at 1.16. Meanwhile, the internal rate of re-

turn was also above the interest rate of 9.72%, so the investment was still profitable. The

cost of electricity was still below the selling price from the state power plant of USD

0.083/kWh, where the selling price from the government was USD 0.121/kWh, so there

was a difference of USD 0.037/Kwh as profit.



feature, we could simulate several different values or two decision variables. Interest

rates varied from 7% to 12%. The results of this analysis are presented in Table 12. The

NPV continued to decrease along with the increase in the interest rate, but the value re-

mained positive. The same trend also occurred in the IRR and B/C ratio. Even though the

NPV was always positive, and the B/C ratio was above 1, the results showed that when

the interest rate was at 10–12%, the IRR was already below the interest rate. Thus, in-

vestment had a percentage return that was greater than the interest rate if the interest rate

was lower or equal to 9%. However, the value of the interest rate was a fluctuating value

depending on the economic conditions of the Indonesian state.


Interest Rate 7% 8% 9% 10% 11% 12%

NPV (USD) 57,096 48,846 41,514 34,975 29,124 23,873

IRR (%) 10.75 9.72 8.71 7.73 6.76 5.80

B/C ratio 1.18 1.16 1.15 1.13 1.12 1.10

LCOE ($0.083/kWh)



Investment costs were also varied to determine the range of investment costs that

still provided benefits. The range of investment costs, according to IRENA was from USD

950 to 1650/kW [41]. If one looks at the comparison of the investment costs in Table 13, in

the range from USD 950 to 1100/kW, it was still profitable because the IRR was above the

interest rate. Meanwhile, above USD 1100/kW, it was no longer profitable because the

IRR was under the base interest rate. In this study, the investment cost, which was the

base case, was USD 950/kWh.


Investment Cost

(USD/kWh) 950 1100 1250 1400 1550 1650

NPV (USD) 48,846 44,681 40,515 36,350 32,184 29,407

B/C ratio 1.16 1.15 1.13 1.12 1.10 1.09

IRR (%) 9.72 8.64 7.62 6.67 5.76 5.18

The solid fuel that used for gasification was oil palm frond and oil palm trunk.

When compared for the two fuels, as shown in Table 14, oil palm trunk resulted in a

higher NPV and IRR, which means that it was profitable to use oil palm trunk as fuel. The

cost for oil palm trunk was $0.025/kg, while oil palm frond was $0.026/kg. The difference

was because the oil palm frond requires additional harvesting costs for each period while

the palm trunk does not. However, the use of oil palm frond and oil palm trunk is still

profitable. The difference is only in the profit margin. However, the price for diesel fuel

was a maximum at $0.47/L or the price of subsidies from the government, so that IRR was

above 8%.








-9

-4

1

6

11

16

21

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

Cas

hfl

ow

(K

US

D)



profitable, as long as the maximum price of diesel fuel is $0.47/L, with a maximum in-

terest rate of 9%. This power plant was calculated to implement small villages with low

to medium economic levels, and electricity was not used for extensive commercial activ-

ities. Thus, it was possible to use diesel fuel at a subsidized price as long as the price was

no more than the maximum price above. If the price and interest rate were to exceed, the

IRR value was under the base case of interest rate. The existence of subsidies from the

government is very influential on the benefits to be obtained from a power plant project.

In addition, the subsidy policy can also attract investors to make investments [8,41,43].



Interest rate

7% 13.60 10.75 7.80 4.72 1.41

8% 12.55 9.72 6.80 3.75 0.47

9% 11.52 8.71 5.82 2.80 (0.45)

10% 10.50 7.73 4.86 1.86 (1.36)

11% 9.51 6.76 3.92 0.94 (2.25)

12% 8.53 5.80 2.99 0.04 (3.12)


results are presented in Table 16. The simulation results of the feed-in tariff was below

the base case of USD 0.12/kWh, the IRR was under the base case of interest rate. Thus, if

there was a decrease in feed-in tariffs from the government under the base case, invest-

ment in power plants does not provide optimal benefits. Based on the pattern of in-

creasing feed tariffs in Indonesia to date, it always increases over a specified period.

Thus, the feed-in tariff can be assumed not to reduce return of investment period because

the value continues to increase. However, decreases were still possible depending on

changes in subsidies and political decisions.


Feed in Tariff

(USD/kWh) 0.102 1.110 0.117 0.124 0.131

NPV (USD) (4581) 16,371 37,323 58,275 79,227

B/C Ratio 0.98 1.05 1.13 1.20 1.27

IRR (%) (1.04) 3.48 7.57 11.44 15.18


Financial risk assessment was carried out to evaluate the effect of economic param-

eters on investment risk. The risk analysis of the power plant project was carried out

using Crystal Ball software®. This software was chosen because of the ease of operation,

and it is compatible with MS Excel® [45]. Another advantage, was that various types of

data distribution can be chosen according to needs. The simulation was conducted with

1,000,000 iterations. The Monte Carlo method was used for the risk analysis as it calcu-

lates with the technique of statistical sampling, operates with random input components,

and has uncertainty [25]. The input variable was simulated with several iterations and

produced several data in the form of probabilities. The normal probability distribution

was used. The selection of a probability distribution model in the Monte Carlo analysis

was essential because it affects the accuracy of the simulation results [43,46,47]. In addi-

tion, the number of iterations must also be adjusted to obtain convergence. With a greater

number of iterations, the mean and standard deviation will be evenly distributed.















analysis, the probability of investment risk was relatively small because the NPV was

always positive, and the IRR had the higher base case interest rate. Besides, with a 50%







Based on the risk analysis of components that affect NPV, 68% of the most signifi-

cant influence was investment cost, while capital cost and revenue were the remainders.

Thus, if the investor can control and reduce investment costs, then it was possible to ob-

tain higher profits. The investment component that was possible to be reduced was the

capital cost of the gasification system. The investment cost was 74.4%, as shown in Figure

9. The gasification system used was foreign-made or made with imported products.

Considering the pilot-scale development experience that has been done, it was possible

to produce gasification systems independently so that investment costs can be reduced.



with low risk, standard deviation analysis was used. The analysis can provide infor-


mation in the form of the types of raw materials used to produce electricity with the

smallest deviation. The mechanism for calculating investment risk from the standard

deviation was carried out by comparing the three fuels used to produce electrical energy,

namely, palm fronds, empty fruit bunch, and oil palm trunks.





lowest standard deviation value and the rupiah value of the frond waste was cheaper

than other types of oil palm waste. The results of these calculations show that the small-

est risk for producing electricity comes from EBT fuel, which comes from the type of

palm frond waste at a price of 0.0259 USD/Kg and was able to generate electricity worth

0.0259 USD/kWh.



Frond

Empty Fruit

Bunch

Oil Palm

Trunk


2 Biodiesel (USD/L) 0.3107 0.3107 0.3107





7 Total 0.4483 0.4498 0.4478







needs of everyday life both in urban and rural areas. The implementation of power

plants, especially in rural areas, has the aim of improving the socio-economic life of the

community. Social influence is expected to be felt in the long term, such as the ability to

read, study, and obtain information, and the addition of skills so that it can open oppor-

tunities for people to be more creative and innovative in developing their ability to face

the vicious cycle of poverty.




















plants has a positive impact on the community’s economy. The community has new

business opportunities including in the fisheries and trade sectors. If this gasification

power plant was built in a coastal area that has biomass potential, the community was

also facilitated by making boreholes so that sufficient water was available, and the es-

tablishment of a fish auction place.

Viewed from an environmental aspect, the implementation of power plants will

have an impact on the environment, starting from the construction process to the opera-

tion. Impacts that occur are possibly both temporary and permanent. The construction of







1. River water

quality

TSS

30%

DO

BOD

COD

Total Phosphate

Fecal Coliform

Total Coliform

2. Air quality SO2

30% NO2

3. Quality of

land





40%

The construction of a power plant that utilizes green land will disrupt vegetation

and also affect the wildlife that exists in the environment. Flue gas produced from the

combustion of diesel engines will cause an increase in air temperature around the power

plant, in addition to the combustion product in the form of CO2 , which causes pollution

or contributes to the emission of greenhouse gases. Water used as a syngas cooler before

it is used on a diesel engine will reduce the water supply around the plant, both for sur-

face and underground water. After the water is used, it becomes wastewater and needs to

be disposed of in the environment. With wastewater disposal, the temperature of the

waste will be higher than the average temperature, and the most dangerous impact is the

pollutants contained in the water, which can cause environmental damage. Therefore,

before wastewater is discharged, it is necessary to treat it first. In addition to liquid waste,

solid waste in the form of ash from gasification is also produced from power plants. The

handling of solid waste must be managed so that it does not have a negative impact.

Furthermore, the level of noise and vibration around the project site will increase; during

plant operations this condition also continues to occur.

4. Conclusions



Comment [M5]: Please confirm

if you have got the copyright to

use the table.

























validation, J.I., B.S. and J.A.P.; data curation, E.N.J.; writing—original draft preparation, A.R.S.;

writing—review and editing, J.A.P.; visualization, A.R.S.; supervision, B.S.; funding acquisition, J.I.

All authors have read and agreed to the published version of the manuscript.





from The Combustion and Energy System Laboratory, Sepuluh Nopember Institute of Technology


Abbreviations



ER Equivalent Ratio

AR Air Ratio









PBP Payback Period

Nomenclature


y Year



i Interest rate (%)


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