Improvement of energy efficiency and quality of street lighting in South Italy as an action of...

lable at ScienceDirect

Energy xxx (2015) 1e15

Contents lists avai

Energy

journal homepage: www.elsevier .com/locate/energy

Improvement of energy efficiency and quality of street lighting inSouth Italy as an action of Sustainable Energy Action Plans. The casestudy of Comiso (RG)

Marco Beccali*, Marina Bonomolo, Giuseppina Ciulla, Alessandra Galatioto,Valerio Lo BranoDEIM-Dipartimento dell'Energia dell'Ingegneria dell'informazione e dei Modelli matematici, Universit�a degli Studi di Palermo, Viale delle Scienze, Bldg. 9,90128, Palermo, Italy

a r t i c l e i n f o

Article history:Received 27 November 2014Received in revised form17 April 2015Accepted 3 May 2015Available online xxx

Keywords:Street lightingEnergy efficiencySustainable energy action plan

* Corresponding author.E-mail addresses: [email protected]

[email protected] (M. Bonomolo), [email protected] (A. Galatioto), loBrano).

http://dx.doi.org/10.1016/j.energy.2015.05.0030360-5442/© 2015 Elsevier Ltd. All rights reserved.

Please cite this article in press as: Beccali M,Sustainable Energy Action Plans. The case s

a b s t r a c t

Existing street lighting systems, in most of South Italy cities, are often inefficient due to the obsolescenceof lamps and luminaires and of ineffective light control systems unable to implement efficient on-off anddimming strategies. Energy efficiency improvement, in street lighting systems, is often one of the keyactions to be adopted by Public Administration in their Sustainable Energy Action Plan in the frameworkof the “Covenant of Majors” activities. As a task of FACTOR 20 project, a set of planning options has beenanalysed and proposed. Particularly, street lighting efficiency projects have been studied for represen-tative case studies. A detailed survey of the public lighting systems, in Comiso, allowed represent currentperformance figures such us installed power, luminance and illuminance levels in roads categories,electricity consumption, switching and dimming schedules. A project of system upgrade has beenelaborated. To do this, many lighting simulations, energy and economic assessments in three scenarioshave been performed. The obtained results show that high improvements of the lighting quality areforeseeable together with large energy and economic saving. An economic sensitivity analysis, has shownhow the performance can change. The proposed methodology can be applied in many similar South Italycities.

© 2015 Elsevier Ltd. All rights reserved.

1. Introduction

Electricity consumption for urban lighting is very important inenergy and economic balance for many Italian Municipalities. TheItalian research institute ENEA has developed a study about energyconsumption for lighting which accounts for the 12% of total elec-tricity demand in the public sector. The same study has assessedthat the annual achievable energy saving is about 30% [1].

The European Community provides several policy tools in orderto achieve these savings. One of the most important is the “Cove-nant of Majors” (4400 partners of which 2100 Italian Municipal-ities). It is the main European movement involving local andregional authorities, voluntarily committing to increasing energy

.it (M. Beccali), [email protected] (G. Ciulla),[email protected] (V. Lo

et al., Improvement of energtudy of Comiso (RG), Energy

efficiency and use of renewable energy sources on their territories.By their commitment, Covenant signatories aim to meet andovercome the European Union 20% CO2 reduction objective by2020. The Sustainable Energy Action Plan (SEAP) is the main policyact that each Municipality adopts to reach this goal [2].

Provided that often, the Local Administrations don't know theactual consumption of systems, the first aim of planning is toimprove their knowledge about status and performances of theirinfrastructures. The National Italian project Lumi�ere identifies theLocal Administration's needs about technical-economic factors forenergy saving of lighting systems [3,4]. These are:

- to install more efficient and innovative systems;- to lower energy consumption, costs and environmental impact;- to decrease light pollution.

At the same time, there are some potential critical issues on thefinancial side. In fact, in many EU countries, although Energy Ser-vice Companies (ESCo) are able to take on the economic risks

y efficiency and quality of street lighting in South Italy as an action of(2015), http://dx.doi.org/10.1016/j.energy.2015.05.003

Delta:1_given name

Delta:1_surname

Delta:1_given name

Delta:1_surname

Delta:1_given name

mailto:[email protected]






www.sciencedirect.com/science/journal/03605442

http://www.elsevier.com/locate/energy

http://dx.doi.org/10.1016/j.energy.2015.05.003



M. Beccali et al. / Energy xxx (2015) 1e152

related to this kind of projects, they are usually interested in bigeconomic investments. Furthermore, small companies that couldbe involved in refurbishment of lighting system in small cities, havea difficult access to credit [5,6]. Anyway, several examples offeasible energy strategies, concerning smart lighting planning, havebeen recently adopted in Italy. The Chiaramonte Municipality (PZ)has adopted actions able to grant annual energy savings about687 MWh/y respect to 1732 MWh/y of the baseline [7].

The Municipality of San Giovanni in Marignano (RN) has today anew high performance urban lighting system, with lamps havingan efficiency higher than 100 lumen/W [8]. A remote managementsystem allows the “point to point” control of streetlights for on/offswitching and luminous flux dimming according to vehicular trafficintensity, time schedules and natural light contribution.

The achieved electricity saving is about 44.6% of which the 14%is due to luminaires replacement and 30% is due to remote man-agement. The CO2 emissions saving is 158,500 kg/y [8].

Worldwide, Light Emitting Diode (LED) is emerging as the mostenergy efficient technology for lighting applications. Most of theexisting applications focus on replacing existing street lightingunits with the more energy efficient LED, but without any type ofcontrol to take advantage of its usage pattern [9].

One interesting feature of LED is the ability to reduce its luminousflux without any significant impact upon life and colour [10,11].

Many studies have been made on methodology for indoorlighting control, e.g. methods for illumination control taking intoaccount natural light [12,13]. Other researches discusses energysaving potentials of selected outdoor lamps [14] and their lightingcontrol drivers [15,16].

Moreover, the lighting network can be utilised as a “platform”

for the application of additional “smart” functions. The use of In-formation and Communication Technologies (ICT) can be useful formany other tasks, such as monitoring environmental quality pa-rameters, e.g. air quality (Ozone, PM10) controlling the vehiculartraffic and many other purposes [17e19].

Focussing on energy figures of urban lighting systems re-furbishments, the main technological solutions, able to achieverelevant energy saving, are:

- Installing on/off switching systems, with hourly on/off sched-ules in weekdays and holidays, twilight switches and/or astro-nomical switches [20,21];

- Replacing lamps and/or luminaires with other having good op-tics and high efficiency lamps, in order to reduce the lightingdissipation and to provide correct luminance levels on roadsurfaces, to avoid glare phenomena and to improve the colourrendering [22];

- Installing luminous flow regulators on switchboards. Theinstallation of these devices achieves very important results interms of energy saving. The reduction of absorbed power isobtained decreasing and stabilising the voltage during operatinghours and in the night time, according to the lighting needs.Achievable savings are from 20% to 50%, according to lamps typeand system conditions. Furthermore by this way, it is possible toobtain reductions of O&M costs [23];

- Stabilizing and re-phasing the system. Indeed, the light sourcesrequire voltage not exceeding 5% of nominal value, in this waythe voltage is set to 230 V, in order to avoid a decrease of thelamps life. Moreover, lamps are not stressed, therefore they willhave a longer lifetime [24]. Thanks to the reduction of theovervoltage time it is possible to obtain an additional saving ofabout 5e7% [25].

- Adopting remote management systems. These devices providereal-time management of the energy demand, control andsolving of system fails, economic costs control and ordinary/

Please cite this article in press as: Beccali M, et al., Improvement of energSustainable Energy Action Plans. The case study of Comiso (RG), Energy

extraordinary maintenance management [26,27]. These tech-nologies involve energy savings based on the adopted operationcycles.

- Using Information and Communication Technologies. This kindof devices allows the digital information transmission throughelectrical grid and/or radio waves. By the point-to-point control,it is possible to manage large data series (air quality measures,Closed Circuit TeleVision (CCTV), energy consumption of publicbuildings and vehicular traffic monitoring), in order to improvethe quantity and quality of information available for the citizen.The system could allow the “combination” of lighting in-frastructures with many “smart services” [28,29].

These actions have been introduced in the Guidelines for energyefficient lighting of the Project “Factor 20” [30].

The case study of Comiso Municipality has been analysed withthe aim to investigate how the application of appropriate energyefficiency actions influences the economic and energy consumptionof a typical city of South of Italy. Based on the status quo of Comiso,the authors have chosen to apply two different solutions to achieveenergy saving in street lighting design: the installation of luminousflux regulators and the replacement of existing luminaires withLED. The aim of this work is to assess costs and benefits of suchactions and to propose a methodology suitable to cities withlighting context similar to Comiso Municipality. In fact, the sameapproach could be utilized everywhere. Anyway, being the state ofthe art of public lighting in South Italy, worst than the one in otherareas, the case study is representative of this part of Italy. Thesecities are often characterized by similar lighting infrastructure(lamps and luminaires typologies, absence of control, lack ofmaintenance). The case study is representative of them, alsobecause, it includes typical urban layout of this area. In this way,this work can be used as a key model for other cities in their energyefficiency public lighting projects.

2. Methodology

The adopted methodology includes following steps:

a) review of existing public lighting grid;b) analysis of the energy consumption based on both electrical

energy bills and current operating conditions;c) compilation of a database of the existing public lighting

devices;d) simulation of the status quo of the lighting system and cali-

bration of the model;e) simulations of some energy efficiency actions, such us: sub-

stitution of bulbs with more energy efficient ones, substitu-tion of actual luminaires with cut-off optic, power regulationin the low-traffic night periods;

f) construction of project scenarios;g) calculation of possible electrical energy savings and CO2

emission reductions;h) feasibility based on all economic analysis;

In the following, in Section 3 the a), b) and c) steps aredescribed; in Section 4 the d), e) and f) phases are described and inSection 5 the results relating to g) and h) steps are commented.

3. The Comiso Municipality: state of the art of the publiclighting system and analysis of consumption

The lighting system in Comiso consists in 7674 poles, wall andpendant light systems, equipped with different typologies of lu-minaires and different power of lamps. A field survey of luminaires


M. Beccali et al. / Energy xxx (2015) 1e15 3

typology and suitability was completed. The stock of luminaires ismade of lamp posts, street lighting systems, opal bubble glasssystems, cylindrical opal glass systems, opal glass systems, pendantsystems with aluminium lanterns and floodlight.

The study has shown that most luminaires and lamps are unfitto provide good lighting, according to the Italian and Europeanstandards [31e36]. These standards give minimum requirementsabout luminance and illuminance values and their uniformity to befulfilled in urban public areas and roads.

Most luminaires are unfit to control luminous flux:

- Cast iron lamps posts, being without protection, generate glarephenomena. They are suggested only for small roads and inpresence of high buildings;

- Opal bubble glass systems, when are without protection, createglare and about the 50% of luminous flux scatters upward orsideways. The opal material causes the 20% flux decrease;

- Street light poles with cut-off system have a prismatic cup,which increases the uniformity of light. However, in any case, apart of luminous flux is dissipated. The cut-off system candecrease the dissipation, but it does not achieve energy saving,leading to an oversize of the lamp power.

In Fig.1, a selection of the most representative streets, where theabove mentioned luminaires are installed, is shown.

The entire stock distribution of luminaires can be representedby the groups reported in Table 1. In this abacus it is possible toobserve number and type of luminaires, their photometric diagram,lamp type and installed power.

In each diagram, the curves are referred to a photometric solid ofthe luminaire. In the case of symmetric optic, there is just onephotometric curve (blue curve), while in case of asymmetric optic,there are two curves referred to two orthogonal sections of thephotometric solid (blue and red curves).

It must be noted that the most of photometric diagrams ofinstalled luminaires are not appropriate for street lighting, becausethe light flux is incorrectly oriented. This is true in old traditionalinstallations, especially in the historical centre of the city.

The whole lighting system is powered by 107 switchboards, thatnowadays are not equippedwithvoltage control ordimming system.

Moreover, no data about phases balancing of single switchboardare available. The current installed power is 884.12 kW.

The electrical consumption analysis, made by Comiso Munici-pality, shows that the energy annual consumption, is ~4250 MWh(with 1400.00 tCO2/year emissions). These figures allow to calcu-late an equivalent operating hours at full power about 4800 h/y.

Compared to similar lighting systems without control system,having about ~4200 h/y, this value is considerably high.

The study showed that the annual costs of operation is V

743,885 (average price of electricity is 0.185 V/kWh), including V

70,000 for maintenance costs.

4. Development of energy saving strategies

To solve these critical aspects and to improve the baseline sce-nario, many energy saving strategies have been considered. Threescenarios have been built.

In detail, the aim of scenario 1 is to reduce the energy con-sumption adopting lighting controllers on each switchboard. Thisimplies an efficient management of operating hours and a imple-mentation of a dimming strategy.

Scenario 2 considers only to change the current lampswith 7674LED luminaires. Finally, scenario 3 considers simultaneously theapplication of scenario 1 and scenario 2.


In all the scenarios, the energy saving has been calculatedconsidering the associated installed power and equivalent oper-ating hours, as explained in the following chapters.

4.1. Scenario 1

The deployment of scenario 1 is based on an analysis of vehic-ular and pedestrian traffic results, which has been led to a classi-fication of roads according to EN 13201 standard.

A light control system reduces, through a step-by-step man-agement, the luminous flux on the road surfaces. The steps are setby seasonal and hourly patterns at switchboards level. In detail, thisstrategy allows to reduce energy demand and to optimize lightinglevels on the road, according to the requirements related to theirreal use. The lamps voltage is controlled by the switchboard andenergy saving are proportional to power shaving and operatinghours.

As represented in Fig. 2, the dimming system works from17:45 p.m. to 05:45 a.m. in the winter season and from 20:00 p.m.to 05:00 a.m. in the summer season. In particular, during the firstoperating hours, the design lighting flux (100%) is kept with avoltage of system of 220 V. In early might hours, energy saving isachieved thanks to a second step control with a light flux of 75%,correspondent to a voltage of 200 V. Finally, the most part of savingis due to the third step of the control with a light flux of 50% and avoltage of 180 V [1].

Table 2 shows how the total equivalent operating hours, for atypical winter day, has been calculated.

Similar assumptions have permitted to calculate the equivalentoperating hours for a summer day, equal to 5.5 h, and to collect themonthly equivalent operating hours for a typical winter (January)and summer (June) month.

It must be noted that, being the system stabilized by thecontroller, the voltage does not exceed the 220 V value. However,this scenario does not take into account further energy savingachievable (~5/7%) due to the avoided power surges on the elec-trical network during the night-time, when the voltage could in-crease until 240/245 V. Furthermore, the additional benefit onlifetime of the installed lamps has not been considered.

4.2. Scenario 2

This scenario considers the installation of new luminaires withcut-off optic and equipped with high efficient lamps (LED) [37].

These project hypotheses have been studied in order to providegood visibility during night time, to guarantee road safety, physicand psychological comfort of users and to increase quality of lifeand city aesthetic.

In this case, several simulations have been performed, using theDialux Software [38], for 9 sample roads, representing the largestinstalled typology of lamp/luminaries in Comiso, accounting forabout the 90% of total installed power.

The new luminaires optics are characterized by a proper 3Dphotometry, which have been chosen with the aim to avoid dissi-pation of luminous flux. In particular, according to the mentionedstandard requirements, the luminaires will be replaced with theones listed in the following Table 3.

Fig. 3 shows for each group of lamps the amount of achievablereduction of installed power. Total installed power by scenario 2 is555.91 kW, which is considerably lower than the baseline scenarioone (884.12 kW).

Results, shown in Table 3 and Fig. 3, derive from detailedlighting design for the most representative 9 groups of roads. Foreach road a simulation has been performed to check the compli-ance to standards UNI 11248:2012 and EN 13201:2004. In most


Fig. 1. Comiso street light-system mapping.


cases, without luminaires replacement, the standard requirementsare not respected. Only through the replacement of the luminariesthey were achieved. The required luminance values, Overall Uni-formity (UO), Longitudinal uniformity (UL) and mean illuminancevalue on road surface (Em) are shown in Table 4 for each ReferenceLighting Category of the proposed road groups.

More in detail, the luminance values indicated in Table 4concern different luminous fluxes (F) (100%, 75% and 50%)depending on operating hours. Of course, the variation of the lu-minous flux affects the lighting category. For example, concerning“Strada Provinciale 22”, the variation of the luminous flux from100% to 75% determines the change of the lighting category fromME4b to ME5. This check is required by EN 13201 standard, which


allows the downloading of road class of one step in early night andtwo steps in late night.

For some roads, such as Strada Provinciale 22 and via delleMagnolie, the luminaires have been replaced with others similarthan the existing ones, but with lower power lamps, because theywere fit for that roads. In other cases, such as via Balbo and viaUmberto, the luminaires have been replaced with other having areflector with appropriate optics, but also characterized by a suit-able design for old town centre, reaching also the goal to makeuniform the stock of luminaires in each road [23,39].

Obviously, the different Reference Lighting Categories ofroads, reflectance of materials, luminaires and lamps installed ineach road give opportunities to study different solutions, about


Table 1Abacus of the installed luminaires in Comiso.

Please cite this article in press as: Beccali M, et al., Improvement of energy efficiency and quality of street lighting in South Italy as an action ofSustainable Energy Action Plans. The case study of Comiso (RG), Energy (2015), http://dx.doi.org/10.1016/j.energy.2015.05.003

Fig. 2. Dimming strategies for winter and summer: voltage reduction and equivalent hours.

Table 2Dimming control in a typical winter day.

Hour n. hour Voltage Dimmingcontrol

17:45e18.45 1 220 118.45e19.45 2 220 119.45e20.45 3 220 120.45e21.45 4 200 0.7521.45e22.45 5 200 0.7522.45e23.45 6 180 0.523.45e00.45 7 180 0.500.45e01.45 8 180 0.501.45e02.45 9 180 0.502.45e03.45 10 180 0.503.45e04.45 11 180 0.504.45e05.45 12 180 0.5

Tot. Equivalent Operating hours 8

Fig. 3. Installed power for each lamp/luminaries group. The application of scenario 2.


power, reflector typology and luminaire design. In some cases itwas possible to downsize lamp powers and to obtain an energysaving.

Moreover, the colours of buildings are enhanced and not dis-torted, thanks to better Colour Rendering Index (CRI) of LED lamps(CRI >96) than High Pressure Sodium one (CRI from 20 to 80) andMercury Vapour one (CRI from 33 to 57), as shown in a real colourrendering (Fig. 4).

As shown in lux isolines plots (Table 5), in most cases, the newinstalled luminaires provide a good uniformity of light along roadsurfaces.

Table 3Replacement of lamps in the scenario 2.

Baseline scenario

Type of lamp N. of luminaires Power [W] Totaleach t

A HPS 2858 150 428.7B HPS 2280 70 159.6C HPS 433 100 43.3D HPS 231 150 34.6E HPS 385 70 26.9F HPS 457 100 45.7G HPS 201 100 20.1H HPS 58 150 8.7I HBO 66 125 8.2L HPS 6 1000 6.0M HPS 60 250 15.0N HPS 154 150 23.1O HPS 13 100 1.3P HPS 68 400 27.2Q HPS 13 70 0.9R HBO 5 160 0.8S HPS 140 100 14.0T HBO 48 125 6.0U HPS 198 70 13.8

TOT 7674 884.1


It must be highlighted that, in order to provide good uniformityvalues, it would have been necessary to study a new luminairesdisposition, a shorter distances between adjacent luminaires andfrom luminaires and wall and, sometime, different heights.Nevertheless, in order to avoid extra costs, current distances andheights have been maintained.

The 3D false colour renderings (Fig. 4) show how the luminousflux is accurately oriented on road surfaces.

In Fig. 4 is shown also a comparison between baseline scenarioand the design configuration in scenario 2 with real colourrendering presentation.

Replacement proposed in scenario 2 (LED)

Installed Power forype of lamp [kW]

Power [W] Total Installed Power foreach type of lamp [kW]

0 90 257.20 55 125.40 41 17.75 76 17.55 48 18.40 76 34.70 56.3 11.30 90 5.25 56.3 3.70 600 3.60 150 9.00 90 13.80 31.8 0.40 240 16.31 41 0.50 96 0.40 60 8.40 75 3.66 42 8.3

20 88,412 555.91


Table 4Light requirements according to Italian standard roads classification.

Name of road Reference road category Luminance [cd/m2] UO UL Maintenance factor

f ¼ 100% f ¼ 75% f ¼ 50%

Strada Provinciale 22 ME4b 0.92 0.69 (ME5) 0.46 (ME6) 0.54 0.90 1.23Via Balbo ME4b 1.25 0.937 (ME5) 0.625 (ME6) 0.76 0.76 1.66Via Conte di Torino ME3c 1.27 0.952 (ME4a) 0.635 (ME4b) 0.62 0.82 1.27Via delle Magnolie ME4b 1.05 0.787 (ME5) 0.525 (ME6) 0.59 0.84 1.4Via San Leonardo ME3c 1.80 1.35 (ME4a) 0.90 (ME4b) 0.60 0.60 1.80Via Umberto I ME3c 1.23 0.923 (ME4a) 0.615 (ME4b) 0.44 0.82 1.23Via Verdi ME3c 1.33 0.997 (ME4a) 0.665 (ME4b) 0.73 0.86 1.33

Illuminance Em [lx]f ¼ 100% f ¼ 75% f ¼ 50%

Via Papa Giovanni XXIII CE5 8.22 6.16 4.11 1.10Via San Biagio CE5 13.79 10.34 6.89 1.83


4.3. Scenario 3

This scenario considers at the same time either the imple-mentation of the dimming control technology and the substitutionof the existing lamps with LED. It must be noted that no reliabledata on LED luminous depreciation are available, being their per-formance very variable according to product quality and operatingconditions [40]. Anyway, in order to consider this effect, the designluminous flux has been oversized by a maintenance factor of about20% (see Table 4) [41]. In this way, it is supposed that the installedlamps will be able to provide the design flux still after 75,000 h ofoperation allowing to extend the dimming control for the entirelifespan.

Hence, it was possible to investigate the global effect of suchaction; indeed the application of these actions permits to reducethe energy consumption of 64%.

In addition, as more fully described in following section, fromeconomic point of view this action, involves a lower the returntimes than those provided by the scenario 2, that providing a sig-nificant investment.

5. Results and discussion

Main energy and environmental performances of the threescenarios, compared to the baseline one, are shown in Fig. 5. Thecalculation of energy consumption has been made considering theinstalled power multiplied by the equivalent operating hours at fullload.

As expected, in terms of energy saving, the scenario 3 shows thebest performance: an energy consumption of 1462.06 MWh/y and482.33 equivalent tCO2 emissions.

The CO2 emissions calculation has been done assuming anemission factor of 329.91 equivalent gCO2/kWh [42]. This factor hasbeenmultiplied by the consumption (in kWh) for each scenario, peryear.

In Fig. 6 the monthly energy consumption are shown for eachscenario. Comparing the results of scenario 1 with scenario 2, it ispossible to observe that although the two scenarios are character-ized by almost the same yearly energy consumption, they havedifferent monthly distribution.

In scenario 2, the dimming control system reduces the energyconsumption during the summer season (from June to September)significantly.

Obviously the scenario 3, implementing the actions of scenarios1 and 2, shows the best results of energy saving.

Furthermore, in order to evaluate the global benefit of actions,an economic assessment has been performed.


Equation (1) describes the calculation of the global annualeconomic saving Ra:

Ra ¼ Aþ ½B� C� (1)

The term A is the yearly energy saving due to the reduction ofinstalled power and of the equivalent operating hours (2), the termB represents the yearly cost of substitution of lamps in the baselinescenario (3) and the term C represents the yearly cost of substitu-tion in the i-th scenario and is referred to the actual operating hours(4). Main assumptions are listed in the nomenclature. In details, themost of economic saving derives from the reduction of the oper-ating hours and installed power (less consumption) and from theincreased lifetime of lamps (less maintenance and lampsubstitutions).

A ¼ ��Pbhb � Pphpe

�CkWh

�(2)

B ¼"Xk

i¼1

hbdib

NLiðCLi þ CMDiÞ#

(3)

C ¼"Xk

i¼1

hpdip

NLiðCLi þ CMDiÞ#

(4)

where:

Ra global annual economic saving [V];Pb total installed power in the baseline scenario [kW];hb number of operating hours in the baseline scenario [h/year];Pp design installed power [kW];hpe number of equivalent operating hours in the scenario 1 and 3[h/year];CkWh electricity cost [V/kWh];dib average lifetime of the i-th lamp in the baseline scenario [h];NLi number of lamps;CLi average cost of i-th lamp [V/lamp];CMDi average maintenance cost for substitution of one i-th lamp[V/lamp];hp number of operating hours in the design scenarios [h/year];dip average lifetime of the i-th lamp in the design scenarios [h];

The following assumptions have been made:

hb ¼ 4800 h/year;hpe ¼ 2630 h/year;CkWh ¼ 0.185 V/kWh;


Fig. 4. Comparison between baseline scenario and design configuration in scenario 2. 3D rendering in false and real colour rendering presentations.


dib ¼ 8000 h;CLi ¼ ~335 V/lamp;CMDi ¼ 20 V/lamp;hp ¼ 4040 h/year;dip (HPS) ¼ 17,000 h; dip (LED) ¼ 75,000 h.

In Table 6 the results of this analysis are presented. First andthird columns show Gross and Net Capital Investments. Net CapitalInvestment has been calculated taking into account the actualisedbenefit arising from the trade of Energy Efficiency Certificate (EEC)(or White Certificate) stated by Italian standards [43,44], hence it iscalculated as follows: Gross capital investment - EEC present value.


The White Certificates are official documents certifying that areduction of energy consumption has been achieved by theimplementation of the project. In Italy, EEC are tradable by ESCO.Under such framework, producers, suppliers or electricity distrib-utors, gas and oil are required to undertake energy efficiencymeasures. A White Certificate is an instrument issued by anauthorized body, guaranteeing that a specified amount of energysaving has been achieved in terms of saved Tons of Oil Equivalent(TOE). One EEC is issued every saved TOE (about 5.3 MWh ofelectricity and 1200 Nm3 of natural gas) [45,46].

The evaluation of the amount and value EEC has been carriedout, taking into account the rules of the Technical Standard EEN4/


Table 5Scenario 2. Comparison of the lux isolines on road surfaces in the baseline scenario and design configurations.


Fig. 5. Comparison between energy consumption and equivalent tCO2 emissions in all proposed scenarios.

Fig. 6. Monthly energy consumption in the proposed scenarios.

Fig. 7. Payback Time sensitivity for scenario 2.


11, Annex C and following modifications [47], issued by ItalianEnergy Authority (AEEG). This considers the difference between theactual useful lifetime, of an energy efficiency solution, and theconventional one associated to theWhite Certificates. The numbersof obtained EECs deriving by the implementation of three scenariosare respectively:

Scenario 1: EEC ¼ 670.89Scenario 2: EEC ¼ 550.89Scenario 3: EEC ¼ 972.73

Assuming the current market value of 100V/EEC and a discountrate of 3%, the actualized value of EECs is:

Scenario 1: EECAV ¼ V 335.447,20Scenario 2: EECAV ¼ V 252.293,87Scenario 3: EECAV ¼ V 445.486,00.

Table 6Comparison between three proposed scenarios.

Scenario Gross capitalinvestment (V)

EEC presentvalue (V)

Net capitalinvestment (V)

En(M

1 1,926,200 335,447 1,590,752 1,945

2 2,573,263 252,293 2,320,969 1,537

3 4,499,463 445,486 4,053,977 2,766


The Simple Payback Time for each scenario is reported in Table 5and it has been calculated by the following Equation (5):

SPT ¼�Net Capital Investment

Ra

�(5)

As previously stated, scenario 3 is the best performing one,while the scenario 2 is the worst one. This result takes into accountthe expected energy saving deriving from dimming or lamps sub-stitution, which is counterbalanced by higher investment costs andvariables O&M expenditures. The only installation of LED lamps(scenario 2) without an adequate control system gives a PaybackTime longer than 15 years.

It can be noted that all the proposed investments are sustainablein terms of significant reduction of emissions CO2 and energysaving [47]. Scenario 3 gives the best performance by a significantreconfiguration of the system: a total replacement of light sourcesand the implementation of dimming control system. The PaybackTime is acceptable (10 years), because the maintenance costs areevaluated considering the longest life of the LED systems [40].

ergy savingWh/y) (%)

Economic saving(Ra) (V/y) (%)

Simple paybacktime (years)

CO2 avoided(tCO2/y) (%)

18,540 381,780 4 632.93% 24% 45%75,381 149,006 16 519.72% 6.42% 37%81,718 401,343 10 917.69% 9.90% 66%


Fig. 8. Payback Time sensitivity analysis for scenario 3.

Table 7Simple Payback Time variation of scenario 2.

Payback time sensitivity LED cost

�20% �10% 0% 10% 20%

Electricity cost �20% 18.75 21.63 25.56 31.22 40.10�10% 15.18 17.01 19.35 22.43 26.67

0% 12.75 14.02 15.57 17.50 19.9810% 10.99 11.92 13.02 14.35 15.9720% 9.66 10.37 11.19 12.16 13.30

Table 8Simple Payback Time variation of scenario 3.

Payback time sensitivity LED cost

�20% �10% 0% 10% 20%

Electricity cost �20% 12.43 12.98 13.58 14.24 14.97�10% 10.73 11.14 11.58 12.06 12.58

0% 9.45 9.76 10.10 10.46 10.8510% 8.43 8.68 8.95 9.23 9.5320% 7.62 7.82 8.04 8.26 8.50


Furthermore, it is possible to observe how the initial investmentis strongly influenced by two parameters: the LED lamp cost andthe electricity cost. A sensitivity analysis has been performed inorder to assess their relative influence on the scenarios SPT.

Assuming a reduction by 10% of the LED lamp cost (CLi), due tothe increase of their market penetration, there is a reduction of the

Fig. 9. Simple Payback Time variation of th


Payback Time of 9.94% in scenario 2 and of 3.33% in scenario 3. Onthe contrary, assuming an increment of 10% of the electricity cost(Ckwh), according to actual trend of electricity market, there will bea reduction of Payback Time of 8.46% in scenario 1, of 16.35% inscenario 2 and of 11.36% in scenario 3.

The trend of this indicator, for a variation range between �20%and þ20% of the lamp cost and electricity cost, is reported in Figs. 7and 8.

In all the analysed cases an increase of 20% of the kWh costpermits the most effective reduction of the SPT (from 16 to 12 yearsin the scenario 2 and from 10 to 8 years in the scenario 3). Obvi-ously, also the reduction of the LED cost determines a reduction ofSPT, but less significantly respect to previous case.

Tables 7 and 8 show the SPTcalculated by changing both the LEDcost and the electricity cost for scenario 2 and scenario 3. The boldcells represent the value of SPTobtainedwith reference costs of LEDlamp (V 335) and electricity (0.185 V/kWh).

The overlap of the two previous variations causes a globaloscillation of SPT. In detail, in scenario 2 the SPT varies from 9.66 to40.10 years, while in scenario 3 the range is between 7.62 and 14.97years.

It is worth noting that the application of only the substitution ofthe LED is unsustainable. Indeed only the combination that pro-vides the reduction of the cost of LED by 20% and the increase of theelectric kWh cost leads to a relevant reduction of SPT in both thescenarios.

In particular, Fig. 9 shows 2D and 3D representations of thefunction linking SPT and LED lamp and electricity cost in scenario 3.

It can be noted that the upper left corner of the 2D diagramrepresents the best combination of parameters (þ20% electricitycost and �20% LED cost).

In general, it is interesting to note that the cost of electricity isthe parameter most affecting Simple Payback Time (SPT) and in thelast years this cost has had a constant rising trend (i.e. þ40% be-tween 2011 and 2013 in Italy).

6. Conclusions

Urban lighting, predominantly street lighting, participates withhigh shares in global electricity consumption of most Municipal-ities of South Italy. This fact can be more evident in small citieswhere energy bills are often dominated by lighting service. Op-portunities and benefits of refurbishment or re-design of lightingnetworks are often not clear to Public Administration, unless many

e scenario 3 in 2D and 3D diagrams.



policies have been set to foster this mismatch. In the framework ofthe EU initiative “Covenant of Majors”, Municipalities have todevelop a Sustainable Energy Action Plan (SEAP) as the main policyact to reach the objectives of energy saving. An analysis of a casestudy of a South Italy city is presented. The goal is to provide amethod to assess savings, to select technologies options and to givea proof of achievable energy saving and CO2 emissions reduction.Projects must respect lighting standard requirements regardingsafety and comfort in urban area. The adoption of high efficientlight sources such as LED allows to achieve good energy saving andcontributes to have a greater colour rendering, bringing back agreater aspect to the city. Also new control and dimming strategiescan gives excellent results. For all the analysed scenarios, the resultsof an economic analysis are quite satisfactory, provided that the LEDcost is today relatively high. This factor is counterbalanced by thevery high achievable savings in energy consumption and mainte-nance costs. This research suggests that only substitution of lightsources results insufficient to achieve real economic benefits for thePublic Administrations, but a matching between correct actionsand a smart use of public facilities is the forward way in order tosupport the necessary energy saving actions. In fact, nowadays, thecost of such efficient light sources and of the electricity are themainfactors influencing the global economic performances of urbanlighting system refurbishment. An expected reduction of lightsources costs as well as an increase of electricity price will makepossible to reduce the Payback Time of such investment. Anyway,the proposed actions can be included in Sustainable Energy ActionPlans also under current economic framework if a proper designand mix of technologies is implemented. By the way, a carefullighting design that considers roads typologies and their re-quirements can give, not only economic improvements, but betterconditions to citizens life. In addition, a new lighting infrastructurecan be the basis of a “smart network”, a possible starting pointtoward a wider application in designing a “smart city” [48].

Acknowledgements

This research has been carried out in the framework of the EULIFE project (LIFE08 ENV/IT 000430) Factor 20. Authors would liketo thank the Head of Regional Energy Department Dr. MaurizioPirillo, the Professor Giorgio Beccali and the Head of MunicipalTechnical Department of Comiso (RG) Eng. Giuseppe Saddemi.

Nomenclature

Em average road surface illuminance (lx)Lm average road surface luminance (of a carriageway of a

road) (cd/m2)UO Overall uniformity (of road surface luminance)UI Longitudinal uniformity (of road surface luminance of a

carriage way)HPS High Pressure SodiumHBO Mercury LampEEC Energy Efficiency CertificateEECAv Energy Efficiency Certificate Actualized Value (V)Ra global annual economic saving [V];Pb total installed power in the baseline scenario [kW];hb number of operating hours in the baseline scenario [h/

year];Pp design installed power [kW];hpe number of equivalent operating hours in the scenario 1

and 3 [h/year];CkWh electricity cost [V/kWh];dib average lifetime of the i-th lamp in the baseline scenario

[h];


NLi number of lamps;CLi average cost of i-th lamp [V/lamp];CMDi average maintenance cost for substitution of one i-th

lamp [V/lamp];hp number of operating hours in the design scenarios [h/

year];dip average lifetime of the i-th lamp in the design scenarios

[h];

References

[1] Annunziato M, Bucci F, Meloni C, Moretti F, Pizzuti S. LINEE GUIDA: I fonda-mentali per una gestione efficiente degli impianti di pubblica illuminazione.2012. Report ENEA e Agenzia nazionale per le nuove tecnologie, l'energia e losviluppo economico sostenibile.

[2] http://www.covenantofmayors.eu/index_en.htmlLast view: Dec 2013.[3] Annunziato M, Giuliani G, Gozo N, Honorati Consonni C, Frascone A, Bucci F,

et al. Progetto Lumi�ere: Efficienza Energetica nell’Illuminazione Pubblica.Percorso e metodologia di sviluppo. 2012. Report ENEA e Agenzia nazionaleper le nuove tecnologie, l'energia e lo sviluppo economico sostenibile.

[4] http://www.progettolumiere.enea.it/it/lumiere_it.htmlLast view: Dec 2013.[5] Stuart E, Larsena PH, Goldmana CA, Gilliganc D. A method to estimate the size

and remaining market potential of the U.S. ESCO (energy service company)industry. Energy 2014;362:371e7.

[6] Suhonena Okkonenb L. The Energy Services Company (ESCo) as businessmodel for heat entrepreneurship-A case study of North Karelia, Finland. En-ergy Policy 2013;783:787e861.

[7] http://mycovenant.eumayors.eu/docs/seap/4909_1356609130.pdfLast view:Dec 2013.

[8] http://www.eumayors.eu/about/signatories_en.html?city_id¼6337&overviewLast view: Dec 2013.

[9] Pipattanasomporn M, Rahaman S, Flory I, Teklu Y. Engineering design andassessment of a demand-sensitive LED street lighting system. Sustain EnergyTechnol Assess 2014;136:146e7.

[10] NEMA. Guidelines on the application of dimming to high intensity dischargelamps, LSD 14e2002.

[11] Ji Y, Wolsey R. Lighting answers: dimming systems for highintensity dischargelamps. Light Answers 1994;4. ISSN: 1069e0050.

[12] Pandharipande A, Caicedo D. Daylight integrated illumination control of LEDsystems based on enhanced presence sensing. Energy Build 2011;944:950e1043.

[13] Soori PK, Vishwas M. Lighting control strategy for energy efficient officelighting system design. Energy Build 2013;329:337e66.

[14] Wei Y, Hui SYR, Chung HS-H. Energy saving of large-scale high-intensitydischarge lamp lighting networks using a central reactive power controlsystem. IEEE Trans Ind Electron 2009;3069:3078e156.

[15] Chiu H-J, Lo Y-K, Chen J-T, Cheng S-J, Lin C-Y, Mou S-C. A high-efficiencydimmable LED driver for low-power lighting applications. IEEE Trans IndElectron 2010;735:743e57.

[16] Gacio D, Alonso JM, Garcia J, Campa L, Crespo MJ, Rico-Secades M. PWM seriesdimming for slow-dynamics HPF LED drivers: the high-frequency approach.IEEE Trans Ind Electron 2012;1717:1727e59.

[17] Menga R, Grattieri W. Linee Guida Operative per la realizzazione di impianti diPubblica illuminazione, SSE e sviluppo dei Sistemi Elettrici. CESI Report. Feb.2009. dei Servizi di Pubblica Utilit�a, LEIMA srl, 2013.

[18] Marsal-Llacuna ML, Colomer-Llin�as J, Mel�endez-Frigola J. Lessons in urbanmonitoring taken from sustainable and livable cities to better address theSmart Cities initiative. Technol Forecast Soc Change 2015;90:611e22.

[19] http://epp.eurostat.ec.europa.eu/portal/page/portal/region_cities/city_urban-Last view: Nov 2014.

[20] Howell EK. Photoelectric controls for street lights. Electr Eng 1961;780:785e880.

[21] Gutierrez-Escolar A, Castillo-Martinez A, Gomez-Pulido JM, Gutierrez-Martinez JM, Stapic Z, Medina-Merodio JA. A study to improve the quality ofstreet lighting in Spain. Energies 2015;976:994e8.

[22] Yang SH, Lin JS, Juang FS, Chou DC, Chung MH, Chen CM, et al. White lightemitting diodes (LEDs) with good color rendering indices (CRI) and high lu-minous efficiencies by the encapsulation of mixed and double-deck phos-phors. Curr Appl Phys 2013;931:934e1013.

[23] Kostic M, Djokic L. Recommendations for energy efficient and visuallyacceptable street lighting. Energy 2009;1565:1572e634.

[24] Huang B-J, Hsu P-C, Wu M-S, Tang C-W. Study of system dynamics model andcontrol of a high-power LED lighting luminaire. Energy 2007;2187:2198e232.

[25] Bl�anquez FR, Rebollo E, Blazquez F, Platero CA, Frias P. High-efficiency voltageregulator and stabilizer for outdoor lighting installations. Proc 13th IEEE IntConf 2012;136:142.

[26] Fonseca CC, Pantoni RP, Brand~ao D. Public street lighting remote operationand supervision system. Comput Stand Interfaces 2015;25:34e8.

[27] Zotos N, Stergiopoulos C, Anastasopoulos K, Bogdos G, Pallis E, Skianis C. CaseStudy of a dimmable outdoor lighting system with intelligent management


http://refhub.elsevier.com/S0360-5442(15)00537-X/sref1





















































































and remote control. In: Telecommunications and Multimedia (TEMU). Pro-ceedings of IEEE International Conference, 43; 2012. p. 48.

[28] Haans A, Kort YA. Light distribution in dynamic street lighting: two experi-mental studies on its effects on perceived safety, prospect, concealment, andescape. J Environ Psychol 2012;342:352e432.

[29] Radulovic D, Skok S, Kirincic V. Energy efficiency public lighting managementin the cities. Energy 2011;1908:1915e36.

[30] Lo Brano V, Beccali M, Cellura M, Ciulla G, Galatioto A, Guarino F, et al.Sostenibilit�a energetico-ambientale nei comuni siciliani, Assessorato Region-ale per l’Energia e dei servizi di Servizi di Pubblica Utilit�a. Regione Siciliana.

[31] EC 1e2013 UNI 11248:2012, Light and lighting, Road lighting e Selection oflighting classes.

[32] CEN/TR 13201e1:2014, Light and lighting, Road lighting e Part 1: Perfor-mance requirements.

[33] EN 13201e2:2004, Light and lighting, Road lighting e Part 2: Performancerequirements.

[34] EN 13201e3:2004, Light and lighting, Road lighting e Part 3: Calculation ofperformance.

[35] EN 13201e3:2004/AC2007, Light and lighting, Road lighting e Part 3:Calculation of performance.

[36] EN 13201e4:2004, Light and lighting, Road lighting e Part 4: Methods ofmeasuring lighting performance.

[37] Chang MH, Sandborn P, Pecht M, Yung WK, Wang W. A return on investmentanalysis of applying health monitoring to LED lighting systems. MicroelectronReliab 2015;527:537e55.


[38] http://www.dial.de/DIAL/it/dialux.htmlLast view: Apr 2015.[39] Kocet V. Contemporary urban lighting and lighting of old city centres and

historic sites. In: Green building Council of Croatia, Dubrovnik; April 6e8,2011.

[40] Coureaux IM, Manzano E. The energy impact of luminaire depreciation onurban lighting. Energy Sustain Dev 2013;357:362e417.

[41] CALiPER summary report, DOE solid-state lighting CALiPER program summaryof results. October 2009. Prepared for the U.S. Department of Energy by PacificNorthwest National Laboratory: Round 9 of Product Testing.

[42] http://www.sinanet.isprambiente.it/it/sia-ispra/serie-storiche-emissioni/fat-tori-di-emissione-per-la-produzione-ed-il-consumo-di-energia-elettrica-in-italia/viewLast view: Nov 25th 2014.

[43] Nuova individuazione degli obiettivi quantitativi nazionali di risparmioenergetico e sviluppo delle fonti rinnovabili, di cui all'art. 16, comma 4, delD.Lgs. 23 maggio 2000, n. 164, D. M. 20 Luglio 2004.

[44] http://www.gse.it/it/CertificatiBianchi/Pages/default.aspxLast view: Nov 25th2014.

[45] https://www.mercatoelettrico.org/it/Mercati/TEE/CosaSonoTee.aspxLastview: Nov 25th 2014.

[46] EEN 4/11. Deliberazione 5 maggio 2011, Allegato C.[47] The Institution of Lighting Engineers. The outdoor lighting guide. Taylor &

Francis; 2005, ISBN 0415370078.[48] Lazaroiu GC, Roscia M. Definition methodology for the smart cities model.

Energy 2012;326:332e47.






























Improvement of energy efficiency and quality of street lighting in South Italy as an action of...

Documents

Transcript of Improvement of energy efficiency and quality of street lighting in South Italy as an action of...