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Improvement of energy efficiency and quality of street lighting in South Italy as an action of Sustainable Energy Action Plans. The case study of Comiso (RG)
Energy xxx (2015) 1e15
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Improvement of energy efficiency and quality of street lighting in South Italy as an action of Sustainable Energy Action Plans. The case study of Comiso (RG) Marco Beccali*, Marina Bonomolo, Giuseppina Ciulla, Alessandra Galatioto, Valerio Lo Brano degli Studi di Palermo, Viale delle Scienze, Bldg. 9, DEIM-Dipartimento dell'Energia dell'Ingegneria dell'informazione e dei Modelli matematici, Universita 90128, Palermo, Italy
a r t i c l e i n f o
a b s t r a c t
Article history: Received 27 November 2014 Received in revised form 17 April 2015 Accepted 3 May 2015 Available online xxx
Existing street lighting systems, in most of South Italy cities, are often inefficient due to the obsolescence of lamps and luminaires and of ineffective light control systems unable to implement efficient on-off and dimming strategies. Energy efficiency improvement, in street lighting systems, is often one of the key actions to be adopted by Public Administration in their Sustainable Energy Action Plan in the framework of the “Covenant of Majors” activities. As a task of FACTOR 20 project, a set of planning options has been analysed and proposed. Particularly, street lighting efficiency projects have been studied for representative case studies. A detailed survey of the public lighting systems, in Comiso, allowed represent current performance figures such us installed power, luminance and illuminance levels in roads categories, electricity consumption, switching and dimming schedules. A project of system upgrade has been elaborated. To do this, many lighting simulations, energy and economic assessments in three scenarios have been performed. The obtained results show that high improvements of the lighting quality are foreseeable together with large energy and economic saving. An economic sensitivity analysis, has shown how the performance can change. The proposed methodology can be applied in many similar South Italy cities. © 2015 Elsevier Ltd. All rights reserved.
Keywords: Street lighting Energy efficiency Sustainable energy action plan
1. Introduction Electricity consumption for urban lighting is very important in energy and economic balance for many Italian Municipalities. The Italian research institute ENEA has developed a study about energy consumption for lighting which accounts for the 12% of total electricity demand in the public sector. The same study has assessed that the annual achievable energy saving is about 30% [1]. The European Community provides several policy tools in order to achieve these savings. One of the most important is the “Covenant of Majors” (4400 partners of which 2100 Italian Municipalities). It is the main European movement involving local and regional authorities, voluntarily committing to increasing energy
* Corresponding author. E-mail addresses: [email protected] (M. Beccali), marina. [email protected] (M. Bonomolo), [email protected] (G. Ciulla), [email protected] (A. Galatioto), [email protected] (V. Lo Brano).
efficiency and use of renewable energy sources on their territories. By their commitment, Covenant signatories aim to meet and overcome the European Union 20% CO2 reduction objective by 2020. The Sustainable Energy Action Plan (SEAP) is the main policy act that each Municipality adopts to reach this goal [2]. Provided that often, the Local Administrations don't know the actual consumption of systems, the first aim of planning is to improve their knowledge about status and performances of their re identifies the infrastructures. The National Italian project Lumie Local Administration's needs about technical-economic factors for energy 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 the financial side. In fact, in many EU countries, although Energy Service Companies (ESCo) are able to take on the economic risks
http://dx.doi.org/10.1016/j.energy.2015.05.003 0360-5442/© 2015 Elsevier Ltd. All rights reserved.
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 of Sustainable Energy Action Plans. The case study of Comiso (RG), Energy (2015), http://dx.doi.org/10.1016/j.energy.2015.05.003
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related to this kind of projects, they are usually interested in big economic investments. Furthermore, small companies that could be involved in refurbishment of lighting system in small cities, have a difficult access to credit [5,6]. Anyway, several examples of feasible energy strategies, concerning smart lighting planning, have been recently adopted in Italy. The Chiaramonte Municipality (PZ) has adopted actions able to grant annual energy savings about 687 MWh/y respect to 1732 MWh/y of the baseline [7]. The Municipality of San Giovanni in Marignano (RN) has today a new high performance urban lighting system, with lamps having an efficiency higher than 100 lumen/W [8]. A remote management system allows the “point to point” control of streetlights for on/off switching and luminous flux dimming according to vehicular traffic intensity, 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 management. The CO2 emissions saving is 158,500 kg/y [8]. Worldwide, Light Emitting Diode (LED) is emerging as the most energy efficient technology for lighting applications. Most of the existing applications focus on replacing existing street lighting units with the more energy efficient LED, but without any type of control to take advantage of its usage pattern [9]. One interesting feature of LED is the ability to reduce its luminous flux without any significant impact upon life and colour [10,11]. Many studies have been made on methodology for indoor lighting control, e.g. methods for illumination control taking into account natural light [12,13]. Other researches discusses energy saving potentials of selected outdoor lamps [14] and their lighting control drivers [15,16]. Moreover, the lighting network can be utilised as a “platform” for the application of additional “smart” functions. The use of Information and Communication Technologies (ICT) can be useful for many other tasks, such as monitoring environmental quality parameters, e.g. air quality (Ozone, PM10) controlling the vehicular traffic and many other purposes [17e19]. Focussing on energy figures of urban lighting systems refurbishments, the main technological solutions, able to achieve relevant energy saving, are: - Installing on/off switching systems, with hourly on/off schedules in weekdays and holidays, twilight switches and/or astronomical switches [20,21]; - Replacing lamps and/or luminaires with other having good optics and high efficiency lamps, in order to reduce the lighting dissipation and to provide correct luminance levels on road surfaces, to avoid glare phenomena and to improve the colour rendering [22]; - Installing luminous flow regulators on switchboards. The installation of these devices achieves very important results in terms of energy saving. The reduction of absorbed power is obtained decreasing and stabilising the voltage during operating hours and in the night time, according to the lighting needs. Achievable savings are from 20% to 50%, according to lamps type and system conditions. Furthermore by this way, it is possible to obtain reductions of O&M costs [23]; - Stabilizing and re-phasing the system. Indeed, the light sources require voltage not exceeding 5% of nominal value, in this way the voltage is set to 230 V, in order to avoid a decrease of the lamps life. Moreover, lamps are not stressed, therefore they will have a longer lifetime [24]. Thanks to the reduction of the overvoltage time it is possible to obtain an additional saving of about 5e7% [25]. - Adopting remote management systems. These devices provide real-time management of the energy demand, control and solving of system fails, economic costs control and ordinary/
extraordinary maintenance management [26,27]. These technologies involve energy savings based on the adopted operation cycles. - Using Information and Communication Technologies. This kind of devices allows the digital information transmission through electrical 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 public buildings and vehicular traffic monitoring), in order to improve the quantity and quality of information available for the citizen. The system could allow the “combination” of lighting infrastructures with many “smart services” [28,29]. These actions have been introduced in the Guidelines for energy efficient lighting of the Project “Factor 20” [30]. The case study of Comiso Municipality has been analysed with the aim to investigate how the application of appropriate energy efficiency actions influences the economic and energy consumption of a typical city of South of Italy. Based on the status quo of Comiso, the authors have chosen to apply two different solutions to achieve energy saving in street lighting design: the installation of luminous flux regulators and the replacement of existing luminaires with LED. The aim of this work is to assess costs and benefits of such actions and to propose a methodology suitable to cities with lighting context similar to Comiso Municipality. In fact, the same approach could be utilized everywhere. Anyway, being the state of the art of public lighting in South Italy, worst than the one in other areas, the case study is representative of this part of Italy. These cities are often characterized by similar lighting infrastructure (lamps and luminaires typologies, absence of control, lack of maintenance). The case study is representative of them, also because, 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 energy efficiency 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 calibration of the model; e) simulations of some energy efficiency actions, such us: substitution of bulbs with more energy efficient ones, substitution of actual luminaires with cut-off optic, power regulation in 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 are described; in Section 4 the d), e) and f) phases are described and in Section 5 the results relating to g) and h) steps are commented. 3. The Comiso Municipality: state of the art of the public lighting system and analysis of consumption The lighting system in Comiso consists in 7674 poles, wall and pendant light systems, equipped with different typologies of luminaires and different power of lamps. A field survey of luminaires
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 of Sustainable Energy Action Plans. The case study of Comiso (RG), Energy (2015), http://dx.doi.org/10.1016/j.energy.2015.05.003
M. Beccali et al. / Energy xxx (2015) 1e15
typology and suitability was completed. The stock of luminaires is made of lamp posts, street lighting systems, opal bubble glass systems, cylindrical opal glass systems, opal glass systems, pendant systems with aluminium lanterns and floodlight. The study has shown that most luminaires and lamps are unfit to provide good lighting, according to the Italian and European standards [31e36]. These standards give minimum requirements about luminance and illuminance values and their uniformity to be fulfilled in urban public areas and roads. Most luminaires are unfit to control luminous flux: - Cast iron lamps posts, being without protection, generate glare phenomena. They are suggested only for small roads and in presence of high buildings; - Opal bubble glass systems, when are without protection, create glare and about the 50% of luminous flux scatters upward or sideways. 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, a part of luminous flux is dissipated. The cut-off system can decrease 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 the above mentioned luminaires are installed, is shown. The entire stock distribution of luminaires can be represented by the groups reported in Table 1. In this abacus it is possible to observe number and type of luminaires, their photometric diagram, lamp type and installed power. In each diagram, the curves are referred to a photometric solid of the luminaire. In the case of symmetric optic, there is just one photometric curve (blue curve), while in case of asymmetric optic, there are two curves referred to two orthogonal sections of the photometric solid (blue and red curves). It must be noted that the most of photometric diagrams of installed luminaires are not appropriate for street lighting, because the light flux is incorrectly oriented. This is true in old traditional installations, especially in the historical centre of the city. The whole lighting system is powered by 107 switchboards, that nowadays are not equipped with voltage control or dimming system. Moreover, no data about phases balancing of single switchboard are available. The current installed power is 884.12 kW. The electrical consumption analysis, made by Comiso Municipality, shows that the energy annual consumption, is ~4250 MWh (with 1400.00 tCO2/year emissions). These figures allow to calculate 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 scenario, many energy saving strategies have been considered. Three scenarios have been built. In detail, the aim of scenario 1 is to reduce the energy consumption adopting lighting controllers on each switchboard. This implies an efficient management of operating hours and a implementation of a dimming strategy. Scenario 2 considers only to change the current lamps with 7674 LED luminaires. Finally, scenario 3 considers simultaneously the application of scenario 1 and scenario 2.
3
In all the scenarios, the energy saving has been calculated considering the associated installed power and equivalent operating hours, as explained in the following chapters. 4.1. Scenario 1 The deployment of scenario 1 is based on an analysis of vehicular and pedestrian traffic results, which has been led to a classification of roads according to EN 13201 standard. A light control system reduces, through a step-by-step management, the luminous flux on the road surfaces. The steps are set by seasonal and hourly patterns at switchboards level. In detail, this strategy allows to reduce energy demand and to optimize lighting levels on the road, according to the requirements related to their real use. The lamps voltage is controlled by the switchboard and energy saving are proportional to power shaving and operating hours. As represented in Fig. 2, the dimming system works from 17:45 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 first operating hours, the design lighting flux (100%) is kept with a voltage of system of 220 V. In early might hours, energy saving is achieved thanks to a second step control with a light flux of 75%, correspondent to a voltage of 200 V. Finally, the most part of saving is due to the third step of the control with a light flux of 50% and a voltage of 180 V [1]. Table 2 shows how the total equivalent operating hours, for a typical winter day, has been calculated. Similar assumptions have permitted to calculate the equivalent operating hours for a summer day, equal to 5.5 h, and to collect the monthly equivalent operating hours for a typical winter (January) and summer (June) month. It must be noted that, being the system stabilized by the controller, the voltage does not exceed the 220 V value. However, this scenario does not take into account further energy saving achievable (~5/7%) due to the avoided power surges on the electrical network during the night-time, when the voltage could increase until 240/245 V. Furthermore, the additional benefit on lifetime of the installed lamps has not been considered. 4.2. Scenario 2 This scenario considers the installation of new luminaires with cut-off optic and equipped with high efficient lamps (LED) [37]. These project hypotheses have been studied in order to provide good visibility during night time, to guarantee road safety, physic and psychological comfort of users and to increase quality of life and city aesthetic. In this case, several simulations have been performed, using the Dialux Software [38], for 9 sample roads, representing the largest installed typology of lamp/luminaries in Comiso, accounting for about the 90% of total installed power. The new luminaires optics are characterized by a proper 3D photometry, which have been chosen with the aim to avoid dissipation of luminous flux. In particular, according to the mentioned standard requirements, the luminaires will be replaced with the ones listed in the following Table 3. Fig. 3 shows for each group of lamps the amount of achievable reduction of installed power. Total installed power by scenario 2 is 555.91 kW, which is considerably lower than the baseline scenario one (884.12 kW). Results, shown in Table 3 and Fig. 3, derive from detailed lighting design for the most representative 9 groups of roads. For each road a simulation has been performed to check the compliance to standards UNI 11248:2012 and EN 13201:2004. In most
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 of Sustainable Energy Action Plans. The case study of Comiso (RG), Energy (2015), http://dx.doi.org/10.1016/j.energy.2015.05.003
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Fig. 1. Comiso street light-system mapping.
cases, without luminaires replacement, the standard requirements are not respected. Only through the replacement of the luminaries they were achieved. The required luminance values, Overall Uniformity (UO), Longitudinal uniformity (UL) and mean illuminance value on road surface (Em) are shown in Table 4 for each Reference Lighting Category of the proposed road groups. More in detail, the luminance values indicated in Table 4 concern different luminous fluxes (F) (100%, 75% and 50%) depending on operating hours. Of course, the variation of the luminous flux affects the lighting category. For example, concerning “Strada Provinciale 22”, the variation of the luminous flux from 100% to 75% determines the change of the lighting category from ME4b to ME5. This check is required by EN 13201 standard, which
allows the downloading of road class of one step in early night and two steps in late night. For some roads, such as Strada Provinciale 22 and via delle Magnolie, the luminaires have been replaced with others similar than the existing ones, but with lower power lamps, because they were fit for that roads. In other cases, such as via Balbo and via Umberto, the luminaires have been replaced with other having a reflector with appropriate optics, but also characterized by a suitable design for old town centre, reaching also the goal to make uniform the stock of luminaires in each road [23,39]. Obviously, the different Reference Lighting Categories of roads, reflectance of materials, luminaires and lamps installed in each road give opportunities to study different solutions, about
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 of Sustainable Energy Action Plans. The case study of Comiso (RG), Energy (2015), http://dx.doi.org/10.1016/j.energy.2015.05.003
Table 1 Abacus 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 of Sustainable Energy Action Plans. The case study of Comiso (RG), Energy (2015), http://dx.doi.org/10.1016/j.energy.2015.05.003
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 of Sustainable Energy Action Plans. The case study of Comiso (RG), Energy (2015), http://dx.doi.org/10.1016/j.energy.2015.05.003
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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 of Sustainable Energy Action Plans. The case study of Comiso (RG), Energy (2015), http://dx.doi.org/10.1016/j.energy.2015.05.003
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Fig. 2. Dimming strategies for winter and summer: voltage reduction and equivalent hours.
Table 2 Dimming control in a typical winter day. Hour
n. hour
Voltage
Dimming control
17:45e18.45 18.45e19.45 19.45e20.45 20.45e21.45 21.45e22.45 22.45e23.45 23.45e00.45 00.45e01.45 01.45e02.45 02.45e03.45 03.45e04.45 04.45e05.45
1 2 3 4 5 6 7 8 9 10 11 12
220 220 220 200 200 180 180 180 180 180 180 180
1 1 1 0.75 0.75 0.5 0.5 0.5 0.5 0.5 0.5 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 it was possible to downsize lamp powers and to obtain an energy saving. Moreover, the colours of buildings are enhanced and not distorted, thanks to better Colour Rendering Index (CRI) of LED lamps (CRI >96) than High Pressure Sodium one (CRI from 20 to 80) and Mercury Vapour one (CRI from 33 to 57), as shown in a real colour rendering (Fig. 4). As shown in lux isolines plots (Table 5), in most cases, the new installed luminaires provide a good uniformity of light along road surfaces.
It must be highlighted that, in order to provide good uniformity values, it would have been necessary to study a new luminaires disposition, a shorter distances between adjacent luminaires and from luminaires and wall and, sometime, different heights. Nevertheless, in order to avoid extra costs, current distances and heights have been maintained. The 3D false colour renderings (Fig. 4) show how the luminous flux is accurately oriented on road surfaces. In Fig. 4 is shown also a comparison between baseline scenario and the design configuration in scenario 2 with real colour rendering presentation.
Table 3 Replacement of lamps in the scenario 2. Baseline scenario Type of lamp A B C D E F G H I L M N O P Q R S T U TOT
HPS HPS HPS HPS HPS HPS HPS HPS HBO HPS HPS HPS HPS HPS HPS HBO HPS HBO HPS
Replacement proposed in scenario 2 (LED) N. of luminaires
Power [W]
Total Installed Power for each type of lamp [kW]
Power [W]
Total Installed Power for each type of lamp [kW]
2858 2280 433 231 385 457 201 58 66 6 60 154 13 68 13 5 140 48 198
150 70 100 150 70 100 100 150 125 1000 250 150 100 400 70 160 100 125 70
428.70 159.60 43.30 34.65 26.95 45.70 20.10 8.70 8.25 6.00 15.00 23.10 1.30 27.20 0.91 0.80 14.00 6.00 13.86
90 55 41 76 48 76 56.3 90 56.3 600 150 90 31.8 240 41 96 60 75 42
257.2 125.4 17.7 17.5 18.4 34.7 11.3 5.2 3.7 3.6 9.0 13.8 0.4 16.3 0.5 0.4 8.4 3.6 8.3
884.120
88,412
555.91
7674
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 of Sustainable Energy Action Plans. The case study of Comiso (RG), Energy (2015), http://dx.doi.org/10.1016/j.energy.2015.05.003
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Table 4 Light requirements according to Italian standard roads classification. Name of road
Strada Provinciale 22 Via Balbo Via Conte di Torino Via delle Magnolie Via San Leonardo Via Umberto I Via Verdi
Reference road category
ME4b ME4b ME3c ME4b ME3c ME3c ME3c
Luminance [cd/m2]
f ¼ 100%
f ¼ 75%
f ¼ 50%
0.92 1.25 1.27 1.05 1.80 1.23 1.33
0.69 (ME5) 0.937 (ME5) 0.952 (ME4a) 0.787 (ME5) 1.35 (ME4a) 0.923 (ME4a) 0.997 (ME4a)
0.46 (ME6) 0.625 (ME6) 0.635 (ME4b) 0.525 (ME6) 0.90 (ME4b) 0.615 (ME4b) 0.665 (ME4b)
Illuminance Em [lx]
Via Papa Giovanni XXIII Via San Biagio
CE5 CE5
f ¼ 100%
f ¼ 75%
f ¼ 50%
8.22 13.79
6.16 10.34
4.11 6.89
4.3. Scenario 3 This scenario considers at the same time either the implementation of the dimming control technology and the substitution of the existing lamps with LED. It must be noted that no reliable data on LED luminous depreciation are available, being their performance very variable according to product quality and operating conditions [40]. Anyway, in order to consider this effect, the design luminous flux has been oversized by a maintenance factor of about 20% (see Table 4) [41]. In this way, it is supposed that the installed lamps will be able to provide the design flux still after 75,000 h of operation allowing to extend the dimming control for the entire lifespan. Hence, it was possible to investigate the global effect of such action; indeed the application of these actions permits to reduce the energy consumption of 64%. In addition, as more fully described in following section, from economic point of view this action, involves a lower the return times than those provided by the scenario 2, that providing a significant investment.
UL
Maintenance factor
0.54 0.76 0.62 0.59 0.60 0.44 0.73
0.90 0.76 0.82 0.84 0.60 0.82 0.86
1.23 1.66 1.27 1.4 1.80 1.23 1.33
1.10 1.83
Equation (1) describes the calculation of the global annual economic saving Ra:
Ra ¼ A þ ½B C
(1)
The term A is the yearly energy saving due to the reduction of installed power and of the equivalent operating hours (2), the term B represents the yearly cost of substitution of lamps in the baseline scenario (3) and the term C represents the yearly cost of substitution in the i-th scenario and is referred to the actual operating hours (4). Main assumptions are listed in the nomenclature. In details, the most of economic saving derives from the reduction of the operating hours and installed power (less consumption) and from the increased lifetime of lamps (less maintenance and lamp substitutions).
A¼
Pb hb Pp hpe CkWh "
k X h
b
B¼
i¼1
"
5. Results and discussion Main energy and environmental performances of the three scenarios, compared to the baseline one, are shown in Fig. 5. The calculation of energy consumption has been made considering the installed power multiplied by the equivalent operating hours at full load. As expected, in terms of energy saving, the scenario 3 shows the best performance: an energy consumption of 1462.06 MWh/y and 482.33 equivalent tCO2 emissions. The CO2 emissions calculation has been done assuming an emission factor of 329.91 equivalent gCO2/kWh [42]. This factor has been multiplied by the consumption (in kWh) for each scenario, per year. In Fig. 6 the monthly energy consumption are shown for each scenario. Comparing the results of scenario 1 with scenario 2, it is possible to observe that although the two scenarios are characterized by almost the same yearly energy consumption, they have different monthly distribution. In scenario 2, the dimming control system reduces the energy consumption during the summer season (from June to September) significantly. Obviously the scenario 3, implementing the actions of scenarios 1 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.
UO
C¼
dib
k X hp i¼1
dip
(2) #
NLi ðCLi þ CMDi Þ
(3) #
NLi ðCLi þ CMDi Þ
(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;
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 of Sustainable Energy Action Plans. The case study of Comiso (RG), Energy (2015), http://dx.doi.org/10.1016/j.energy.2015.05.003
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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 and third columns show Gross and Net Capital Investments. Net Capital Investment has been calculated taking into account the actualised benefit arising from the trade of Energy Efficiency Certificate (EEC) (or White Certificate) stated by Italian standards [43,44], hence it is calculated as follows: Gross capital investment - EEC present value.
The White Certificates are official documents certifying that a reduction of energy consumption has been achieved by the implementation of the project. In Italy, EEC are tradable by ESCO. Under such framework, producers, suppliers or electricity distributors, gas and oil are required to undertake energy efficiency measures. A White Certificate is an instrument issued by an authorized body, guaranteeing that a specified amount of energy saving has been achieved in terms of saved Tons of Oil Equivalent (TOE). One EEC is issued every saved TOE (about 5.3 MWh of electricity and 1200 Nm3 of natural gas) [45,46]. The evaluation of the amount and value EEC has been carried out, taking into account the rules of the Technical Standard EEN4/
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 of Sustainable Energy Action Plans. The case study of Comiso (RG), Energy (2015), http://dx.doi.org/10.1016/j.energy.2015.05.003
Table 5 Scenario 2. Comparison of the lux isolines on road surfaces in the baseline scenario and design configurations.
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Fig. 5. Comparison between energy consumption and equivalent tCO2 emissions in all proposed scenarios.
Fig. 7. Payback Time sensitivity for scenario 2.
Fig. 6. Monthly energy consumption in the proposed scenarios.
11, Annex C and following modifications [47], issued by Italian Energy Authority (AEEG). This considers the difference between the actual useful lifetime, of an energy efficiency solution, and the conventional one associated to the White Certificates. The numbers of obtained EECs deriving by the implementation of three scenarios are respectively: Scenario 1: EEC ¼ 670.89 Scenario 2: EEC ¼ 550.89 Scenario 3: EEC ¼ 972.73 Assuming the current market value of 100V/EEC and a discount rate of 3%, the actualized value of EECs is: Scenario 1: EECAV ¼ V 335.447,20 Scenario 2: EECAV ¼ V 252.293,87 Scenario 3: EECAV ¼ V 445.486,00.
The Simple Payback Time for each scenario is reported in Table 5 and 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 account the expected energy saving deriving from dimming or lamps substitution, which is counterbalanced by higher investment costs and variables O&M expenditures. The only installation of LED lamps (scenario 2) without an adequate control system gives a Payback Time longer than 15 years. It can be noted that all the proposed investments are sustainable in terms of significant reduction of emissions CO2 and energy saving [47]. Scenario 3 gives the best performance by a significant reconfiguration of the system: a total replacement of light sources and the implementation of dimming control system. The Payback Time is acceptable (10 years), because the maintenance costs are evaluated considering the longest life of the LED systems [40].
Table 6 Comparison between three proposed scenarios. Scenario
Gross capital investment (V)
EEC present value (V)
Net capital investment (V)
Energy saving (MWh/y) (%)
Economic saving (Ra) (V/y) (%)
1
1,926,200
335,447
1,590,752
2
2,573,263
252,293
2,320,969
3
4,499,463
445,486
4,053,977
1,918,540 45% 1,575,381 37% 2,781,718 66%
381,780 24% 149,006 6.42% 401,343 9.90%
Simple payback time (years) 4 16 10
CO2 avoided (tCO2/y) (%) 632.93 45% 519.72 37% 917.69 66%
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M. Beccali et al. / Energy xxx (2015) 1e15
Fig. 8. Payback Time sensitivity analysis for scenario 3. Table 7 Simple Payback Time variation of scenario 2. Payback time sensitivity
Electricity cost
20% 10% 0% 10% 20%
LED cost 20%
10%
0%
10%
20%
18.75 15.18 12.75 10.99 9.66
21.63 17.01 14.02 11.92 10.37
25.56 19.35 15.57 13.02 11.19
31.22 22.43 17.50 14.35 12.16
40.10 26.67 19.98 15.97 13.30
Table 8 Simple Payback Time variation of scenario 3. Payback time sensitivity
Electricity cost
20% 10% 0% 10% 20%
LED cost 20%
10%
0%
10%
20%
12.43 10.73 9.45 8.43 7.62
12.98 11.14 9.76 8.68 7.82
13.58 11.58 10.10 8.95 8.04
14.24 12.06 10.46 9.23 8.26
14.97 12.58 10.85 9.53 8.50
13
Payback Time of 9.94% in scenario 2 and of 3.33% in scenario 3. On the contrary, assuming an increment of 10% of the electricity cost (Ckwh), according to actual trend of electricity market, there will be a reduction of Payback Time of 8.46% in scenario 1, of 16.35% in scenario 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. 7 and 8. In all the analysed cases an increase of 20% of the kWh cost permits the most effective reduction of the SPT (from 16 to 12 years in the scenario 2 and from 10 to 8 years in the scenario 3). Obviously, also the reduction of the LED cost determines a reduction of SPT, but less significantly respect to previous case. Tables 7 and 8 show the SPT calculated by changing both the LED cost and the electricity cost for scenario 2 and scenario 3. The bold cells represent the value of SPT obtained with reference costs of LED lamp (V 335) and electricity (0.185 V/kWh). The overlap of the two previous variations causes a global oscillation of SPT. In detail, in scenario 2 the SPT varies from 9.66 to 40.10 years, while in scenario 3 the range is between 7.62 and 14.97 years. It is worth noting that the application of only the substitution of the LED is unsustainable. Indeed only the combination that provides the reduction of the cost of LED by 20% and the increase of the electric kWh cost leads to a relevant reduction of SPT in both the scenarios. In particular, Fig. 9 shows 2D and 3D representations of the function linking SPT and LED lamp and electricity cost in scenario 3. It can be noted that the upper left corner of the 2D diagram represents the best combination of parameters (þ20% electricity cost and 20% LED cost). In general, it is interesting to note that the cost of electricity is the parameter most affecting Simple Payback Time (SPT) and in the last years this cost has had a constant rising trend (i.e. þ40% between 2011 and 2013 in Italy).
6. Conclusions Furthermore, it is possible to observe how the initial investment is strongly influenced by two parameters: the LED lamp cost and the electricity cost. A sensitivity analysis has been performed in order to assess their relative influence on the scenarios SPT. Assuming a reduction by 10% of the LED lamp cost (CLi), due to the increase of their market penetration, there is a reduction of the
Urban lighting, predominantly street lighting, participates with high shares in global electricity consumption of most Municipalities of South Italy. This fact can be more evident in small cities where energy bills are often dominated by lighting service. Opportunities and benefits of refurbishment or re-design of lighting networks are often not clear to Public Administration, unless many
Fig. 9. Simple Payback Time variation of the scenario 3 in 2D and 3D diagrams.
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policies have been set to foster this mismatch. In the framework of the EU initiative “Covenant of Majors”, Municipalities have to develop a Sustainable Energy Action Plan (SEAP) as the main policy act to reach the objectives of energy saving. An analysis of a case study of a South Italy city is presented. The goal is to provide a method to assess savings, to select technologies options and to give a proof of achievable energy saving and CO2 emissions reduction. Projects must respect lighting standard requirements regarding safety and comfort in urban area. The adoption of high efficient light sources such as LED allows to achieve good energy saving and contributes to have a greater colour rendering, bringing back a greater aspect to the city. Also new control and dimming strategies can gives excellent results. For all the analysed scenarios, the results of an economic analysis are quite satisfactory, provided that the LED cost is today relatively high. This factor is counterbalanced by the very high achievable savings in energy consumption and maintenance costs. This research suggests that only substitution of light sources results insufficient to achieve real economic benefits for the Public Administrations, but a matching between correct actions and a smart use of public facilities is the forward way in order to support the necessary energy saving actions. In fact, nowadays, the cost of such efficient light sources and of the electricity are the main factors influencing the global economic performances of urban lighting system refurbishment. An expected reduction of light sources costs as well as an increase of electricity price will make possible to reduce the Payback Time of such investment. Anyway, the proposed actions can be included in Sustainable Energy Action Plans also under current economic framework if a proper design and mix of technologies is implemented. By the way, a careful lighting design that considers roads typologies and their requirements can give, not only economic improvements, but better conditions to citizens life. In addition, a new lighting infrastructure can be the basis of a “smart network”, a possible starting point toward a wider application in designing a “smart city” [48]. Acknowledgements This research has been carried out in the framework of the EU LIFE project (LIFE08 ENV/IT 000430) Factor 20. Authors would like to thank the Head of Regional Energy Department Dr. Maurizio Pirillo, the Professor Giorgio Beccali and the Head of Municipal Technical Department of Comiso (RG) Eng. Giuseppe Saddemi. Nomenclature Em Lm UO UI HPS HBO EEC EECAv Ra Pb hb Pp hpe CkWh dib
average road surface illuminance (lx) average road surface luminance (of a carriageway of a road) (cd/m2) Overall uniformity (of road surface luminance) Longitudinal uniformity (of road surface luminance of a carriage way) High Pressure Sodium Mercury Lamp Energy Efficiency Certificate Energy Efficiency Certificate Actualized Value (V) global annual economic saving [V]; total installed power in the baseline scenario [kW]; number of operating hours in the baseline scenario [h/ year]; design installed power [kW]; number of equivalent operating hours in the scenario 1 and 3 [h/year]; electricity cost [V/kWh]; average lifetime of the i-th lamp in the baseline scenario [h];
NLi CLi CMDi hp dip
number of lamps; average cost of i-th lamp [V/lamp]; average maintenance cost for substitution of one i-th lamp [V/lamp]; number of operating hours in the design scenarios [h/ year]; 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 fondamentali per una gestione efficiente degli impianti di pubblica illuminazione. 2012. Report ENEA e Agenzia nazionale per le nuove tecnologie, l'energia e lo sviluppo 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, re: Efficienza Energetica nell’Illuminazione Pubblica. et al. Progetto Lumie Percorso e metodologia di sviluppo. 2012. Report ENEA e Agenzia nazionale per 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 business model for heat entrepreneurship-A case study of North Karelia, Finland. Energy 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 and assessment of a demand-sensitive LED street lighting system. Sustain Energy Technol Assess 2014;136:146e7. [10] NEMA. Guidelines on the application of dimming to high intensity discharge lamps, LSD 14e2002. [11] Ji Y, Wolsey R. Lighting answers: dimming systems for highintensity discharge lamps. Light Answers 1994;4. ISSN: 1069e0050. [12] Pandharipande A, Caicedo D. Daylight integrated illumination control of LED systems based on enhanced presence sensing. Energy Build 2011;944: 950e1043. [13] Soori PK, Vishwas M. Lighting control strategy for energy efficient office lighting system design. Energy Build 2013;329:337e66. [14] Wei Y, Hui SYR, Chung HS-H. Energy saving of large-scale high-intensity discharge lamp lighting networks using a central reactive power control system. 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-efficiency dimmable LED driver for low-power lighting applications. IEEE Trans Ind Electron 2010;735:743e57. [16] Gacio D, Alonso JM, Garcia J, Campa L, Crespo MJ, Rico-Secades M. PWM series dimming 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 di Pubblica illuminazione, SSE e sviluppo dei Sistemi Elettrici. CESI Report. Feb. , LEIMA srl, 2013. 2009. dei Servizi di Pubblica Utilita s J, Mele ndez-Frigola J. Lessons in urban [18] Marsal-Llacuna ML, Colomer-Llina monitoring taken from sustainable and livable cities to better address the Smart Cities initiative. Technol Forecast Soc Change 2015;90:611e22. [19] http://epp.eurostat.ec.europa.eu/portal/page/portal/region_cities/city_urbanLast 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, GutierrezMartinez JM, Stapic Z, Medina-Merodio JA. A study to improve the quality of street lighting in Spain. Energies 2015;976:994e8. [22] Yang SH, Lin JS, Juang FS, Chou DC, Chung MH, Chen CM, et al. White light emitting diodes (LEDs) with good color rendering indices (CRI) and high luminous efficiencies by the encapsulation of mixed and double-deck phosphors. Curr Appl Phys 2013;931:934e1013. [23] Kostic M, Djokic L. Recommendations for energy efficient and visually acceptable street lighting. Energy 2009;1565:1572e634. [24] Huang B-J, Hsu P-C, Wu M-S, Tang C-W. Study of system dynamics model and control of a high-power LED lighting luminaire. Energy 2007;2187:2198e232. nquez FR, Rebollo E, Blazquez F, Platero CA, Frias P. High-efficiency voltage [25] Bla regulator and stabilizer for outdoor lighting installations. Proc 13th IEEE Int Conf 2012;136:142. ~o D. Public street lighting remote operation [26] Fonseca CC, Pantoni RP, Branda and supervision system. Comput Stand Interfaces 2015;25:34e8. [27] Zotos N, Stergiopoulos C, Anastasopoulos K, Bogdos G, Pallis E, Skianis C. Case Study of a dimmable outdoor lighting system with intelligent management
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 of Sustainable Energy Action Plans. The case study of Comiso (RG), Energy (2015), http://dx.doi.org/10.1016/j.energy.2015.05.003
M. Beccali et al. / Energy xxx (2015) 1e15
[28]
[29] [30]
[31] [32] [33] [34] [35] [36] [37]
and remote control. In: Telecommunications and Multimedia (TEMU). Proceedings of IEEE International Conference, 43; 2012. p. 48. Haans A, Kort YA. Light distribution in dynamic street lighting: two experimental studies on its effects on perceived safety, prospect, concealment, and escape. J Environ Psychol 2012;342:352e432. Radulovic D, Skok S, Kirincic V. Energy efficiency public lighting management in the cities. Energy 2011;1908:1915e36. Lo Brano V, Beccali M, Cellura M, Ciulla G, Galatioto A, Guarino F, et al. energetico-ambientale nei comuni siciliani, Assessorato RegionSostenibilita ale per l’Energia e dei servizi di Servizi di Pubblica Utilit a. Regione Siciliana. EC 1e2013 UNI 11248:2012, Light and lighting, Road lighting e Selection of lighting classes. CEN/TR 13201e1:2014, Light and lighting, Road lighting e Part 1: Performance requirements. EN 13201e2:2004, Light and lighting, Road lighting e Part 2: Performance requirements. EN 13201e3:2004, Light and lighting, Road lighting e Part 3: Calculation of performance. EN 13201e3:2004/AC2007, Light and lighting, Road lighting e Part 3: Calculation of performance. EN 13201e4:2004, Light and lighting, Road lighting e Part 4: Methods of measuring lighting performance. Chang MH, Sandborn P, Pecht M, Yung WK, Wang W. A return on investment analysis of applying health monitoring to LED lighting systems. Microelectron Reliab 2015;527:537e55.
15
[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 on urban lighting. Energy Sustain Dev 2013;357:362e417. [41] CALiPER summary report, DOE solid-state lighting CALiPER program summary of results. October 2009. Prepared for the U.S. Department of Energy by Pacific Northwest National Laboratory: Round 9 of Product Testing. [42] http://www.sinanet.isprambiente.it/it/sia-ispra/serie-storiche-emissioni/fattori-di-emissione-per-la-produzione-ed-il-consumo-di-energia-elettrica-initalia/viewLast view: Nov 25th 2014. [43] Nuova individuazione degli obiettivi quantitativi nazionali di risparmio energetico e sviluppo delle fonti rinnovabili, di cui all'art. 16, comma 4, del D.Lgs. 23 maggio 2000, n. 164, D. M. 20 Luglio 2004. [44] http://www.gse.it/it/CertificatiBianchi/Pages/default.aspxLast view: Nov 25th 2014. [45] https://www.mercatoelettrico.org/it/Mercati/TEE/CosaSonoTee.aspxLast view: 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.
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Improvement of energy efficiency and quality of street lighting in South Italy as an action of Sustainable Energy Action Plans. The case study of Comiso (RG) Marco Beccali*, Marina Bonomolo, Giuseppina Ciulla, Alessandra Galatioto, Valerio Lo Brano degli Studi di Palermo, Viale delle Scienze, Bldg. 9, DEIM-Dipartimento dell'Energia dell'Ingegneria dell'informazione e dei Modelli matematici, Universita 90128, Palermo, Italy
a r t i c l e i n f o
a b s t r a c t
Article history: Received 27 November 2014 Received in revised form 17 April 2015 Accepted 3 May 2015 Available online xxx
Existing street lighting systems, in most of South Italy cities, are often inefficient due to the obsolescence of lamps and luminaires and of ineffective light control systems unable to implement efficient on-off and dimming strategies. Energy efficiency improvement, in street lighting systems, is often one of the key actions to be adopted by Public Administration in their Sustainable Energy Action Plan in the framework of the “Covenant of Majors” activities. As a task of FACTOR 20 project, a set of planning options has been analysed and proposed. Particularly, street lighting efficiency projects have been studied for representative case studies. A detailed survey of the public lighting systems, in Comiso, allowed represent current performance figures such us installed power, luminance and illuminance levels in roads categories, electricity consumption, switching and dimming schedules. A project of system upgrade has been elaborated. To do this, many lighting simulations, energy and economic assessments in three scenarios have been performed. The obtained results show that high improvements of the lighting quality are foreseeable together with large energy and economic saving. An economic sensitivity analysis, has shown how the performance can change. The proposed methodology can be applied in many similar South Italy cities. © 2015 Elsevier Ltd. All rights reserved.
Keywords: Street lighting Energy efficiency Sustainable energy action plan
1. Introduction Electricity consumption for urban lighting is very important in energy and economic balance for many Italian Municipalities. The Italian research institute ENEA has developed a study about energy consumption for lighting which accounts for the 12% of total electricity demand in the public sector. The same study has assessed that the annual achievable energy saving is about 30% [1]. The European Community provides several policy tools in order to achieve these savings. One of the most important is the “Covenant of Majors” (4400 partners of which 2100 Italian Municipalities). It is the main European movement involving local and regional authorities, voluntarily committing to increasing energy
* Corresponding author. E-mail addresses: [email protected] (M. Beccali), marina. [email protected] (M. Bonomolo), [email protected] (G. Ciulla), [email protected] (A. Galatioto), [email protected] (V. Lo Brano).
efficiency and use of renewable energy sources on their territories. By their commitment, Covenant signatories aim to meet and overcome the European Union 20% CO2 reduction objective by 2020. The Sustainable Energy Action Plan (SEAP) is the main policy act that each Municipality adopts to reach this goal [2]. Provided that often, the Local Administrations don't know the actual consumption of systems, the first aim of planning is to improve their knowledge about status and performances of their re identifies the infrastructures. The National Italian project Lumie Local Administration's needs about technical-economic factors for energy 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 the financial side. In fact, in many EU countries, although Energy Service Companies (ESCo) are able to take on the economic risks
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related to this kind of projects, they are usually interested in big economic investments. Furthermore, small companies that could be involved in refurbishment of lighting system in small cities, have a difficult access to credit [5,6]. Anyway, several examples of feasible energy strategies, concerning smart lighting planning, have been recently adopted in Italy. The Chiaramonte Municipality (PZ) has adopted actions able to grant annual energy savings about 687 MWh/y respect to 1732 MWh/y of the baseline [7]. The Municipality of San Giovanni in Marignano (RN) has today a new high performance urban lighting system, with lamps having an efficiency higher than 100 lumen/W [8]. A remote management system allows the “point to point” control of streetlights for on/off switching and luminous flux dimming according to vehicular traffic intensity, 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 management. The CO2 emissions saving is 158,500 kg/y [8]. Worldwide, Light Emitting Diode (LED) is emerging as the most energy efficient technology for lighting applications. Most of the existing applications focus on replacing existing street lighting units with the more energy efficient LED, but without any type of control to take advantage of its usage pattern [9]. One interesting feature of LED is the ability to reduce its luminous flux without any significant impact upon life and colour [10,11]. Many studies have been made on methodology for indoor lighting control, e.g. methods for illumination control taking into account natural light [12,13]. Other researches discusses energy saving potentials of selected outdoor lamps [14] and their lighting control drivers [15,16]. Moreover, the lighting network can be utilised as a “platform” for the application of additional “smart” functions. The use of Information and Communication Technologies (ICT) can be useful for many other tasks, such as monitoring environmental quality parameters, e.g. air quality (Ozone, PM10) controlling the vehicular traffic and many other purposes [17e19]. Focussing on energy figures of urban lighting systems refurbishments, the main technological solutions, able to achieve relevant energy saving, are: - Installing on/off switching systems, with hourly on/off schedules in weekdays and holidays, twilight switches and/or astronomical switches [20,21]; - Replacing lamps and/or luminaires with other having good optics and high efficiency lamps, in order to reduce the lighting dissipation and to provide correct luminance levels on road surfaces, to avoid glare phenomena and to improve the colour rendering [22]; - Installing luminous flow regulators on switchboards. The installation of these devices achieves very important results in terms of energy saving. The reduction of absorbed power is obtained decreasing and stabilising the voltage during operating hours and in the night time, according to the lighting needs. Achievable savings are from 20% to 50%, according to lamps type and system conditions. Furthermore by this way, it is possible to obtain reductions of O&M costs [23]; - Stabilizing and re-phasing the system. Indeed, the light sources require voltage not exceeding 5% of nominal value, in this way the voltage is set to 230 V, in order to avoid a decrease of the lamps life. Moreover, lamps are not stressed, therefore they will have a longer lifetime [24]. Thanks to the reduction of the overvoltage time it is possible to obtain an additional saving of about 5e7% [25]. - Adopting remote management systems. These devices provide real-time management of the energy demand, control and solving of system fails, economic costs control and ordinary/
extraordinary maintenance management [26,27]. These technologies involve energy savings based on the adopted operation cycles. - Using Information and Communication Technologies. This kind of devices allows the digital information transmission through electrical 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 public buildings and vehicular traffic monitoring), in order to improve the quantity and quality of information available for the citizen. The system could allow the “combination” of lighting infrastructures with many “smart services” [28,29]. These actions have been introduced in the Guidelines for energy efficient lighting of the Project “Factor 20” [30]. The case study of Comiso Municipality has been analysed with the aim to investigate how the application of appropriate energy efficiency actions influences the economic and energy consumption of a typical city of South of Italy. Based on the status quo of Comiso, the authors have chosen to apply two different solutions to achieve energy saving in street lighting design: the installation of luminous flux regulators and the replacement of existing luminaires with LED. The aim of this work is to assess costs and benefits of such actions and to propose a methodology suitable to cities with lighting context similar to Comiso Municipality. In fact, the same approach could be utilized everywhere. Anyway, being the state of the art of public lighting in South Italy, worst than the one in other areas, the case study is representative of this part of Italy. These cities are often characterized by similar lighting infrastructure (lamps and luminaires typologies, absence of control, lack of maintenance). The case study is representative of them, also because, 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 energy efficiency 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 calibration of the model; e) simulations of some energy efficiency actions, such us: substitution of bulbs with more energy efficient ones, substitution of actual luminaires with cut-off optic, power regulation in 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 are described; in Section 4 the d), e) and f) phases are described and in Section 5 the results relating to g) and h) steps are commented. 3. The Comiso Municipality: state of the art of the public lighting system and analysis of consumption The lighting system in Comiso consists in 7674 poles, wall and pendant light systems, equipped with different typologies of luminaires and different power of lamps. A field survey of luminaires
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 of Sustainable Energy Action Plans. The case study of Comiso (RG), Energy (2015), http://dx.doi.org/10.1016/j.energy.2015.05.003
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typology and suitability was completed. The stock of luminaires is made of lamp posts, street lighting systems, opal bubble glass systems, cylindrical opal glass systems, opal glass systems, pendant systems with aluminium lanterns and floodlight. The study has shown that most luminaires and lamps are unfit to provide good lighting, according to the Italian and European standards [31e36]. These standards give minimum requirements about luminance and illuminance values and their uniformity to be fulfilled in urban public areas and roads. Most luminaires are unfit to control luminous flux: - Cast iron lamps posts, being without protection, generate glare phenomena. They are suggested only for small roads and in presence of high buildings; - Opal bubble glass systems, when are without protection, create glare and about the 50% of luminous flux scatters upward or sideways. 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, a part of luminous flux is dissipated. The cut-off system can decrease 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 the above mentioned luminaires are installed, is shown. The entire stock distribution of luminaires can be represented by the groups reported in Table 1. In this abacus it is possible to observe number and type of luminaires, their photometric diagram, lamp type and installed power. In each diagram, the curves are referred to a photometric solid of the luminaire. In the case of symmetric optic, there is just one photometric curve (blue curve), while in case of asymmetric optic, there are two curves referred to two orthogonal sections of the photometric solid (blue and red curves). It must be noted that the most of photometric diagrams of installed luminaires are not appropriate for street lighting, because the light flux is incorrectly oriented. This is true in old traditional installations, especially in the historical centre of the city. The whole lighting system is powered by 107 switchboards, that nowadays are not equipped with voltage control or dimming system. Moreover, no data about phases balancing of single switchboard are available. The current installed power is 884.12 kW. The electrical consumption analysis, made by Comiso Municipality, shows that the energy annual consumption, is ~4250 MWh (with 1400.00 tCO2/year emissions). These figures allow to calculate 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 scenario, many energy saving strategies have been considered. Three scenarios have been built. In detail, the aim of scenario 1 is to reduce the energy consumption adopting lighting controllers on each switchboard. This implies an efficient management of operating hours and a implementation of a dimming strategy. Scenario 2 considers only to change the current lamps with 7674 LED luminaires. Finally, scenario 3 considers simultaneously the application of scenario 1 and scenario 2.
3
In all the scenarios, the energy saving has been calculated considering the associated installed power and equivalent operating hours, as explained in the following chapters. 4.1. Scenario 1 The deployment of scenario 1 is based on an analysis of vehicular and pedestrian traffic results, which has been led to a classification of roads according to EN 13201 standard. A light control system reduces, through a step-by-step management, the luminous flux on the road surfaces. The steps are set by seasonal and hourly patterns at switchboards level. In detail, this strategy allows to reduce energy demand and to optimize lighting levels on the road, according to the requirements related to their real use. The lamps voltage is controlled by the switchboard and energy saving are proportional to power shaving and operating hours. As represented in Fig. 2, the dimming system works from 17:45 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 first operating hours, the design lighting flux (100%) is kept with a voltage of system of 220 V. In early might hours, energy saving is achieved thanks to a second step control with a light flux of 75%, correspondent to a voltage of 200 V. Finally, the most part of saving is due to the third step of the control with a light flux of 50% and a voltage of 180 V [1]. Table 2 shows how the total equivalent operating hours, for a typical winter day, has been calculated. Similar assumptions have permitted to calculate the equivalent operating hours for a summer day, equal to 5.5 h, and to collect the monthly equivalent operating hours for a typical winter (January) and summer (June) month. It must be noted that, being the system stabilized by the controller, the voltage does not exceed the 220 V value. However, this scenario does not take into account further energy saving achievable (~5/7%) due to the avoided power surges on the electrical network during the night-time, when the voltage could increase until 240/245 V. Furthermore, the additional benefit on lifetime of the installed lamps has not been considered. 4.2. Scenario 2 This scenario considers the installation of new luminaires with cut-off optic and equipped with high efficient lamps (LED) [37]. These project hypotheses have been studied in order to provide good visibility during night time, to guarantee road safety, physic and psychological comfort of users and to increase quality of life and city aesthetic. In this case, several simulations have been performed, using the Dialux Software [38], for 9 sample roads, representing the largest installed typology of lamp/luminaries in Comiso, accounting for about the 90% of total installed power. The new luminaires optics are characterized by a proper 3D photometry, which have been chosen with the aim to avoid dissipation of luminous flux. In particular, according to the mentioned standard requirements, the luminaires will be replaced with the ones listed in the following Table 3. Fig. 3 shows for each group of lamps the amount of achievable reduction of installed power. Total installed power by scenario 2 is 555.91 kW, which is considerably lower than the baseline scenario one (884.12 kW). Results, shown in Table 3 and Fig. 3, derive from detailed lighting design for the most representative 9 groups of roads. For each road a simulation has been performed to check the compliance to standards UNI 11248:2012 and EN 13201:2004. In most
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 of Sustainable Energy Action Plans. The case study of Comiso (RG), Energy (2015), http://dx.doi.org/10.1016/j.energy.2015.05.003
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Fig. 1. Comiso street light-system mapping.
cases, without luminaires replacement, the standard requirements are not respected. Only through the replacement of the luminaries they were achieved. The required luminance values, Overall Uniformity (UO), Longitudinal uniformity (UL) and mean illuminance value on road surface (Em) are shown in Table 4 for each Reference Lighting Category of the proposed road groups. More in detail, the luminance values indicated in Table 4 concern different luminous fluxes (F) (100%, 75% and 50%) depending on operating hours. Of course, the variation of the luminous flux affects the lighting category. For example, concerning “Strada Provinciale 22”, the variation of the luminous flux from 100% to 75% determines the change of the lighting category from ME4b to ME5. This check is required by EN 13201 standard, which
allows the downloading of road class of one step in early night and two steps in late night. For some roads, such as Strada Provinciale 22 and via delle Magnolie, the luminaires have been replaced with others similar than the existing ones, but with lower power lamps, because they were fit for that roads. In other cases, such as via Balbo and via Umberto, the luminaires have been replaced with other having a reflector with appropriate optics, but also characterized by a suitable design for old town centre, reaching also the goal to make uniform the stock of luminaires in each road [23,39]. Obviously, the different Reference Lighting Categories of roads, reflectance of materials, luminaires and lamps installed in each road give opportunities to study different solutions, about
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Table 1 Abacus of the installed luminaires in Comiso.
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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 of Sustainable Energy Action Plans. The case study of Comiso (RG), Energy (2015), http://dx.doi.org/10.1016/j.energy.2015.05.003
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Fig. 2. Dimming strategies for winter and summer: voltage reduction and equivalent hours.
Table 2 Dimming control in a typical winter day. Hour
n. hour
Voltage
Dimming control
17:45e18.45 18.45e19.45 19.45e20.45 20.45e21.45 21.45e22.45 22.45e23.45 23.45e00.45 00.45e01.45 01.45e02.45 02.45e03.45 03.45e04.45 04.45e05.45
1 2 3 4 5 6 7 8 9 10 11 12
220 220 220 200 200 180 180 180 180 180 180 180
1 1 1 0.75 0.75 0.5 0.5 0.5 0.5 0.5 0.5 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 it was possible to downsize lamp powers and to obtain an energy saving. Moreover, the colours of buildings are enhanced and not distorted, thanks to better Colour Rendering Index (CRI) of LED lamps (CRI >96) than High Pressure Sodium one (CRI from 20 to 80) and Mercury Vapour one (CRI from 33 to 57), as shown in a real colour rendering (Fig. 4). As shown in lux isolines plots (Table 5), in most cases, the new installed luminaires provide a good uniformity of light along road surfaces.
It must be highlighted that, in order to provide good uniformity values, it would have been necessary to study a new luminaires disposition, a shorter distances between adjacent luminaires and from luminaires and wall and, sometime, different heights. Nevertheless, in order to avoid extra costs, current distances and heights have been maintained. The 3D false colour renderings (Fig. 4) show how the luminous flux is accurately oriented on road surfaces. In Fig. 4 is shown also a comparison between baseline scenario and the design configuration in scenario 2 with real colour rendering presentation.
Table 3 Replacement of lamps in the scenario 2. Baseline scenario Type of lamp A B C D E F G H I L M N O P Q R S T U TOT
HPS HPS HPS HPS HPS HPS HPS HPS HBO HPS HPS HPS HPS HPS HPS HBO HPS HBO HPS
Replacement proposed in scenario 2 (LED) N. of luminaires
Power [W]
Total Installed Power for each type of lamp [kW]
Power [W]
Total Installed Power for each type of lamp [kW]
2858 2280 433 231 385 457 201 58 66 6 60 154 13 68 13 5 140 48 198
150 70 100 150 70 100 100 150 125 1000 250 150 100 400 70 160 100 125 70
428.70 159.60 43.30 34.65 26.95 45.70 20.10 8.70 8.25 6.00 15.00 23.10 1.30 27.20 0.91 0.80 14.00 6.00 13.86
90 55 41 76 48 76 56.3 90 56.3 600 150 90 31.8 240 41 96 60 75 42
257.2 125.4 17.7 17.5 18.4 34.7 11.3 5.2 3.7 3.6 9.0 13.8 0.4 16.3 0.5 0.4 8.4 3.6 8.3
884.120
88,412
555.91
7674
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M. Beccali et al. / Energy xxx (2015) 1e15
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Table 4 Light requirements according to Italian standard roads classification. Name of road
Strada Provinciale 22 Via Balbo Via Conte di Torino Via delle Magnolie Via San Leonardo Via Umberto I Via Verdi
Reference road category
ME4b ME4b ME3c ME4b ME3c ME3c ME3c
Luminance [cd/m2]
f ¼ 100%
f ¼ 75%
f ¼ 50%
0.92 1.25 1.27 1.05 1.80 1.23 1.33
0.69 (ME5) 0.937 (ME5) 0.952 (ME4a) 0.787 (ME5) 1.35 (ME4a) 0.923 (ME4a) 0.997 (ME4a)
0.46 (ME6) 0.625 (ME6) 0.635 (ME4b) 0.525 (ME6) 0.90 (ME4b) 0.615 (ME4b) 0.665 (ME4b)
Illuminance Em [lx]
Via Papa Giovanni XXIII Via San Biagio
CE5 CE5
f ¼ 100%
f ¼ 75%
f ¼ 50%
8.22 13.79
6.16 10.34
4.11 6.89
4.3. Scenario 3 This scenario considers at the same time either the implementation of the dimming control technology and the substitution of the existing lamps with LED. It must be noted that no reliable data on LED luminous depreciation are available, being their performance very variable according to product quality and operating conditions [40]. Anyway, in order to consider this effect, the design luminous flux has been oversized by a maintenance factor of about 20% (see Table 4) [41]. In this way, it is supposed that the installed lamps will be able to provide the design flux still after 75,000 h of operation allowing to extend the dimming control for the entire lifespan. Hence, it was possible to investigate the global effect of such action; indeed the application of these actions permits to reduce the energy consumption of 64%. In addition, as more fully described in following section, from economic point of view this action, involves a lower the return times than those provided by the scenario 2, that providing a significant investment.
UL
Maintenance factor
0.54 0.76 0.62 0.59 0.60 0.44 0.73
0.90 0.76 0.82 0.84 0.60 0.82 0.86
1.23 1.66 1.27 1.4 1.80 1.23 1.33
1.10 1.83
Equation (1) describes the calculation of the global annual economic saving Ra:
Ra ¼ A þ ½B C
(1)
The term A is the yearly energy saving due to the reduction of installed power and of the equivalent operating hours (2), the term B represents the yearly cost of substitution of lamps in the baseline scenario (3) and the term C represents the yearly cost of substitution in the i-th scenario and is referred to the actual operating hours (4). Main assumptions are listed in the nomenclature. In details, the most of economic saving derives from the reduction of the operating hours and installed power (less consumption) and from the increased lifetime of lamps (less maintenance and lamp substitutions).
A¼
Pb hb Pp hpe CkWh "
k X h
b
B¼
i¼1
"
5. Results and discussion Main energy and environmental performances of the three scenarios, compared to the baseline one, are shown in Fig. 5. The calculation of energy consumption has been made considering the installed power multiplied by the equivalent operating hours at full load. As expected, in terms of energy saving, the scenario 3 shows the best performance: an energy consumption of 1462.06 MWh/y and 482.33 equivalent tCO2 emissions. The CO2 emissions calculation has been done assuming an emission factor of 329.91 equivalent gCO2/kWh [42]. This factor has been multiplied by the consumption (in kWh) for each scenario, per year. In Fig. 6 the monthly energy consumption are shown for each scenario. Comparing the results of scenario 1 with scenario 2, it is possible to observe that although the two scenarios are characterized by almost the same yearly energy consumption, they have different monthly distribution. In scenario 2, the dimming control system reduces the energy consumption during the summer season (from June to September) significantly. Obviously the scenario 3, implementing the actions of scenarios 1 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.
UO
C¼
dib
k X hp i¼1
dip
(2) #
NLi ðCLi þ CMDi Þ
(3) #
NLi ðCLi þ CMDi Þ
(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;
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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 and third columns show Gross and Net Capital Investments. Net Capital Investment has been calculated taking into account the actualised benefit arising from the trade of Energy Efficiency Certificate (EEC) (or White Certificate) stated by Italian standards [43,44], hence it is calculated as follows: Gross capital investment - EEC present value.
The White Certificates are official documents certifying that a reduction of energy consumption has been achieved by the implementation of the project. In Italy, EEC are tradable by ESCO. Under such framework, producers, suppliers or electricity distributors, gas and oil are required to undertake energy efficiency measures. A White Certificate is an instrument issued by an authorized body, guaranteeing that a specified amount of energy saving has been achieved in terms of saved Tons of Oil Equivalent (TOE). One EEC is issued every saved TOE (about 5.3 MWh of electricity and 1200 Nm3 of natural gas) [45,46]. The evaluation of the amount and value EEC has been carried out, taking into account the rules of the Technical Standard EEN4/
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Table 5 Scenario 2. Comparison of the lux isolines on road surfaces in the baseline scenario and design configurations.
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Fig. 5. Comparison between energy consumption and equivalent tCO2 emissions in all proposed scenarios.
Fig. 7. Payback Time sensitivity for scenario 2.
Fig. 6. Monthly energy consumption in the proposed scenarios.
11, Annex C and following modifications [47], issued by Italian Energy Authority (AEEG). This considers the difference between the actual useful lifetime, of an energy efficiency solution, and the conventional one associated to the White Certificates. The numbers of obtained EECs deriving by the implementation of three scenarios are respectively: Scenario 1: EEC ¼ 670.89 Scenario 2: EEC ¼ 550.89 Scenario 3: EEC ¼ 972.73 Assuming the current market value of 100V/EEC and a discount rate of 3%, the actualized value of EECs is: Scenario 1: EECAV ¼ V 335.447,20 Scenario 2: EECAV ¼ V 252.293,87 Scenario 3: EECAV ¼ V 445.486,00.
The Simple Payback Time for each scenario is reported in Table 5 and 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 account the expected energy saving deriving from dimming or lamps substitution, which is counterbalanced by higher investment costs and variables O&M expenditures. The only installation of LED lamps (scenario 2) without an adequate control system gives a Payback Time longer than 15 years. It can be noted that all the proposed investments are sustainable in terms of significant reduction of emissions CO2 and energy saving [47]. Scenario 3 gives the best performance by a significant reconfiguration of the system: a total replacement of light sources and the implementation of dimming control system. The Payback Time is acceptable (10 years), because the maintenance costs are evaluated considering the longest life of the LED systems [40].
Table 6 Comparison between three proposed scenarios. Scenario
Gross capital investment (V)
EEC present value (V)
Net capital investment (V)
Energy saving (MWh/y) (%)
Economic saving (Ra) (V/y) (%)
1
1,926,200
335,447
1,590,752
2
2,573,263
252,293
2,320,969
3
4,499,463
445,486
4,053,977
1,918,540 45% 1,575,381 37% 2,781,718 66%
381,780 24% 149,006 6.42% 401,343 9.90%
Simple payback time (years) 4 16 10
CO2 avoided (tCO2/y) (%) 632.93 45% 519.72 37% 917.69 66%
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M. Beccali et al. / Energy xxx (2015) 1e15
Fig. 8. Payback Time sensitivity analysis for scenario 3. Table 7 Simple Payback Time variation of scenario 2. Payback time sensitivity
Electricity cost
20% 10% 0% 10% 20%
LED cost 20%
10%
0%
10%
20%
18.75 15.18 12.75 10.99 9.66
21.63 17.01 14.02 11.92 10.37
25.56 19.35 15.57 13.02 11.19
31.22 22.43 17.50 14.35 12.16
40.10 26.67 19.98 15.97 13.30
Table 8 Simple Payback Time variation of scenario 3. Payback time sensitivity
Electricity cost
20% 10% 0% 10% 20%
LED cost 20%
10%
0%
10%
20%
12.43 10.73 9.45 8.43 7.62
12.98 11.14 9.76 8.68 7.82
13.58 11.58 10.10 8.95 8.04
14.24 12.06 10.46 9.23 8.26
14.97 12.58 10.85 9.53 8.50
13
Payback Time of 9.94% in scenario 2 and of 3.33% in scenario 3. On the contrary, assuming an increment of 10% of the electricity cost (Ckwh), according to actual trend of electricity market, there will be a reduction of Payback Time of 8.46% in scenario 1, of 16.35% in scenario 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. 7 and 8. In all the analysed cases an increase of 20% of the kWh cost permits the most effective reduction of the SPT (from 16 to 12 years in the scenario 2 and from 10 to 8 years in the scenario 3). Obviously, also the reduction of the LED cost determines a reduction of SPT, but less significantly respect to previous case. Tables 7 and 8 show the SPT calculated by changing both the LED cost and the electricity cost for scenario 2 and scenario 3. The bold cells represent the value of SPT obtained with reference costs of LED lamp (V 335) and electricity (0.185 V/kWh). The overlap of the two previous variations causes a global oscillation of SPT. In detail, in scenario 2 the SPT varies from 9.66 to 40.10 years, while in scenario 3 the range is between 7.62 and 14.97 years. It is worth noting that the application of only the substitution of the LED is unsustainable. Indeed only the combination that provides the reduction of the cost of LED by 20% and the increase of the electric kWh cost leads to a relevant reduction of SPT in both the scenarios. In particular, Fig. 9 shows 2D and 3D representations of the function linking SPT and LED lamp and electricity cost in scenario 3. It can be noted that the upper left corner of the 2D diagram represents the best combination of parameters (þ20% electricity cost and 20% LED cost). In general, it is interesting to note that the cost of electricity is the parameter most affecting Simple Payback Time (SPT) and in the last years this cost has had a constant rising trend (i.e. þ40% between 2011 and 2013 in Italy).
6. Conclusions Furthermore, it is possible to observe how the initial investment is strongly influenced by two parameters: the LED lamp cost and the electricity cost. A sensitivity analysis has been performed in order to assess their relative influence on the scenarios SPT. Assuming a reduction by 10% of the LED lamp cost (CLi), due to the increase of their market penetration, there is a reduction of the
Urban lighting, predominantly street lighting, participates with high shares in global electricity consumption of most Municipalities of South Italy. This fact can be more evident in small cities where energy bills are often dominated by lighting service. Opportunities and benefits of refurbishment or re-design of lighting networks are often not clear to Public Administration, unless many
Fig. 9. Simple Payback Time variation of the scenario 3 in 2D and 3D diagrams.
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policies have been set to foster this mismatch. In the framework of the EU initiative “Covenant of Majors”, Municipalities have to develop a Sustainable Energy Action Plan (SEAP) as the main policy act to reach the objectives of energy saving. An analysis of a case study of a South Italy city is presented. The goal is to provide a method to assess savings, to select technologies options and to give a proof of achievable energy saving and CO2 emissions reduction. Projects must respect lighting standard requirements regarding safety and comfort in urban area. The adoption of high efficient light sources such as LED allows to achieve good energy saving and contributes to have a greater colour rendering, bringing back a greater aspect to the city. Also new control and dimming strategies can gives excellent results. For all the analysed scenarios, the results of an economic analysis are quite satisfactory, provided that the LED cost is today relatively high. This factor is counterbalanced by the very high achievable savings in energy consumption and maintenance costs. This research suggests that only substitution of light sources results insufficient to achieve real economic benefits for the Public Administrations, but a matching between correct actions and a smart use of public facilities is the forward way in order to support the necessary energy saving actions. In fact, nowadays, the cost of such efficient light sources and of the electricity are the main factors influencing the global economic performances of urban lighting system refurbishment. An expected reduction of light sources costs as well as an increase of electricity price will make possible to reduce the Payback Time of such investment. Anyway, the proposed actions can be included in Sustainable Energy Action Plans also under current economic framework if a proper design and mix of technologies is implemented. By the way, a careful lighting design that considers roads typologies and their requirements can give, not only economic improvements, but better conditions to citizens life. In addition, a new lighting infrastructure can be the basis of a “smart network”, a possible starting point toward a wider application in designing a “smart city” [48]. Acknowledgements This research has been carried out in the framework of the EU LIFE project (LIFE08 ENV/IT 000430) Factor 20. Authors would like to thank the Head of Regional Energy Department Dr. Maurizio Pirillo, the Professor Giorgio Beccali and the Head of Municipal Technical Department of Comiso (RG) Eng. Giuseppe Saddemi. Nomenclature Em Lm UO UI HPS HBO EEC EECAv Ra Pb hb Pp hpe CkWh dib
average road surface illuminance (lx) average road surface luminance (of a carriageway of a road) (cd/m2) Overall uniformity (of road surface luminance) Longitudinal uniformity (of road surface luminance of a carriage way) High Pressure Sodium Mercury Lamp Energy Efficiency Certificate Energy Efficiency Certificate Actualized Value (V) global annual economic saving [V]; total installed power in the baseline scenario [kW]; number of operating hours in the baseline scenario [h/ year]; design installed power [kW]; number of equivalent operating hours in the scenario 1 and 3 [h/year]; electricity cost [V/kWh]; average lifetime of the i-th lamp in the baseline scenario [h];
NLi CLi CMDi hp dip
number of lamps; average cost of i-th lamp [V/lamp]; average maintenance cost for substitution of one i-th lamp [V/lamp]; number of operating hours in the design scenarios [h/ year]; 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 fondamentali per una gestione efficiente degli impianti di pubblica illuminazione. 2012. Report ENEA e Agenzia nazionale per le nuove tecnologie, l'energia e lo sviluppo 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, re: Efficienza Energetica nell’Illuminazione Pubblica. et al. Progetto Lumie Percorso e metodologia di sviluppo. 2012. Report ENEA e Agenzia nazionale per 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 business model for heat entrepreneurship-A case study of North Karelia, Finland. Energy 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 and assessment of a demand-sensitive LED street lighting system. Sustain Energy Technol Assess 2014;136:146e7. [10] NEMA. Guidelines on the application of dimming to high intensity discharge lamps, LSD 14e2002. [11] Ji Y, Wolsey R. Lighting answers: dimming systems for highintensity discharge lamps. Light Answers 1994;4. ISSN: 1069e0050. [12] Pandharipande A, Caicedo D. Daylight integrated illumination control of LED systems based on enhanced presence sensing. Energy Build 2011;944: 950e1043. [13] Soori PK, Vishwas M. Lighting control strategy for energy efficient office lighting system design. Energy Build 2013;329:337e66. [14] Wei Y, Hui SYR, Chung HS-H. Energy saving of large-scale high-intensity discharge lamp lighting networks using a central reactive power control system. 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-efficiency dimmable LED driver for low-power lighting applications. IEEE Trans Ind Electron 2010;735:743e57. [16] Gacio D, Alonso JM, Garcia J, Campa L, Crespo MJ, Rico-Secades M. PWM series dimming 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 di Pubblica illuminazione, SSE e sviluppo dei Sistemi Elettrici. CESI Report. Feb. , LEIMA srl, 2013. 2009. dei Servizi di Pubblica Utilita s J, Mele ndez-Frigola J. Lessons in urban [18] Marsal-Llacuna ML, Colomer-Llina monitoring taken from sustainable and livable cities to better address the Smart Cities initiative. Technol Forecast Soc Change 2015;90:611e22. [19] http://epp.eurostat.ec.europa.eu/portal/page/portal/region_cities/city_urbanLast 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, GutierrezMartinez JM, Stapic Z, Medina-Merodio JA. A study to improve the quality of street lighting in Spain. Energies 2015;976:994e8. [22] Yang SH, Lin JS, Juang FS, Chou DC, Chung MH, Chen CM, et al. White light emitting diodes (LEDs) with good color rendering indices (CRI) and high luminous efficiencies by the encapsulation of mixed and double-deck phosphors. Curr Appl Phys 2013;931:934e1013. [23] Kostic M, Djokic L. Recommendations for energy efficient and visually acceptable street lighting. Energy 2009;1565:1572e634. [24] Huang B-J, Hsu P-C, Wu M-S, Tang C-W. Study of system dynamics model and control of a high-power LED lighting luminaire. Energy 2007;2187:2198e232. nquez FR, Rebollo E, Blazquez F, Platero CA, Frias P. High-efficiency voltage [25] Bla regulator and stabilizer for outdoor lighting installations. Proc 13th IEEE Int Conf 2012;136:142. ~o D. Public street lighting remote operation [26] Fonseca CC, Pantoni RP, Branda and supervision system. Comput Stand Interfaces 2015;25:34e8. [27] Zotos N, Stergiopoulos C, Anastasopoulos K, Bogdos G, Pallis E, Skianis C. Case Study of a dimmable outdoor lighting system with intelligent management
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 of Sustainable Energy Action Plans. The case study of Comiso (RG), Energy (2015), http://dx.doi.org/10.1016/j.energy.2015.05.003
M. Beccali et al. / Energy xxx (2015) 1e15
[28]
[29] [30]
[31] [32] [33] [34] [35] [36] [37]
and remote control. In: Telecommunications and Multimedia (TEMU). Proceedings of IEEE International Conference, 43; 2012. p. 48. Haans A, Kort YA. Light distribution in dynamic street lighting: two experimental studies on its effects on perceived safety, prospect, concealment, and escape. J Environ Psychol 2012;342:352e432. Radulovic D, Skok S, Kirincic V. Energy efficiency public lighting management in the cities. Energy 2011;1908:1915e36. Lo Brano V, Beccali M, Cellura M, Ciulla G, Galatioto A, Guarino F, et al. energetico-ambientale nei comuni siciliani, Assessorato RegionSostenibilita ale per l’Energia e dei servizi di Servizi di Pubblica Utilit a. Regione Siciliana. EC 1e2013 UNI 11248:2012, Light and lighting, Road lighting e Selection of lighting classes. CEN/TR 13201e1:2014, Light and lighting, Road lighting e Part 1: Performance requirements. EN 13201e2:2004, Light and lighting, Road lighting e Part 2: Performance requirements. EN 13201e3:2004, Light and lighting, Road lighting e Part 3: Calculation of performance. EN 13201e3:2004/AC2007, Light and lighting, Road lighting e Part 3: Calculation of performance. EN 13201e4:2004, Light and lighting, Road lighting e Part 4: Methods of measuring lighting performance. Chang MH, Sandborn P, Pecht M, Yung WK, Wang W. A return on investment analysis of applying health monitoring to LED lighting systems. Microelectron Reliab 2015;527:537e55.
15
[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 on urban lighting. Energy Sustain Dev 2013;357:362e417. [41] CALiPER summary report, DOE solid-state lighting CALiPER program summary of results. October 2009. Prepared for the U.S. Department of Energy by Pacific Northwest National Laboratory: Round 9 of Product Testing. [42] http://www.sinanet.isprambiente.it/it/sia-ispra/serie-storiche-emissioni/fattori-di-emissione-per-la-produzione-ed-il-consumo-di-energia-elettrica-initalia/viewLast view: Nov 25th 2014. [43] Nuova individuazione degli obiettivi quantitativi nazionali di risparmio energetico e sviluppo delle fonti rinnovabili, di cui all'art. 16, comma 4, del D.Lgs. 23 maggio 2000, n. 164, D. M. 20 Luglio 2004. [44] http://www.gse.it/it/CertificatiBianchi/Pages/default.aspxLast view: Nov 25th 2014. [45] https://www.mercatoelettrico.org/it/Mercati/TEE/CosaSonoTee.aspxLast view: 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.
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 of Sustainable Energy Action Plans. The case study of Comiso (RG), Energy (2015), http://dx.doi.org/10.1016/j.energy.2015.05.003