Elsevier

Energy

Volume 138, 1 November 2017, Pages 616-628
Energy

Critical analysis of the energy performance indicators for road lighting systems in historical towns of central Italy

https://doi.org/10.1016/j.energy.2017.07.093Get rights and content

Highlights

  • A review of energy performance indicators for road lighting systems is proposed.

  • Four different indicators, valid at international and Italian levels, are analyzed.

  • To support the discussion, the case study of the public lighting of Pisa is used.

  • To evaluate the indicators a systematic procedure based on in situ measurements is used.

  • Strengths/weaknesses of each indicators and critical issues in their use are highlighted.

Abstract

Energy demand represents a global challenge that calls for innovative energy solutions. Road lighting contributes in a small part to the overall worldwide electricity consumption, however the possibilities for energy saving are numerous. The road lighting should provide the required lighting quality, in the most energy efficient way as possible.

In this paper the Authors analyze, compare and discuss the numerical indicators currently used to evaluate the lighting and the energy performance of new-designed and existing road lighting systems. To support the discussion, the use of the case study of road lighting of the historic town center of Pisa is proposed. For the case study the Authors have chosen a significant sample of 20 roads representative of 80 similar roads located in the historic town center. For the sample, geometric surveys, luminance and illuminance measurements, calculation of the national and international energy performance indicators have been carry out. The considerations made by the Authors, obtained with an investigation procedure of general validity, are useful to point out strengths and weaknesses of each indicator and to provide suggestions on the use of the appropriate indicators during the design stage of road lighting systems.

Introduction

Energy demand represents a global issue that calls for innovative local energy solutions, such as the ones generally proposed in Sustainable Action Plans (SEAP) [1]. By the end of May 2016 more than 6700 cities around Europe (3100 in Italy), that involve 211,610,834 inhabitants, started to working on their SEAPs [2]. Public lighting (predominantly on roads) contributes for 2.3% to the global worldwide electricity consumption; thus, energy-efficient programs in this field are very welcome, since the possibilities for energy saving in road lighting are numerous and sometimes even enable reductions in electricity consumptions of more than 30% [3], [4]. In 2005, in Europe, road lighting consumed a notable amount of energy: approximately 35 TWh [5]. In 2010, in the Netherlands, about 0.8 TWh per year were used by municipalities for public lighting, accounting for 60% of the local government's energy consumption [6]. In the same year, in Italy, the national consumption for lighting was about 50.8 TWh per year and, of this amount, 6.1 TWh per year were used for public lighting [7].

Currently, towns throughout the world are engaged in road lighting refurbishment, carried out with the changeover to more efficient luminaires, in some cases at the end of the economic life of the existing ones, in others before the end. Several studies have shown that urban interventions on lighting can lead to positive results [8], [9], [10], [11], [12], since public lighting is an essential element of urban environments [13]. Public lighting should: provide good visibility conditions, reduce potential hazards by illuminating objects in and along the roadways [14], [15], [16], influence the emotions of the observers.

With increasing consideration of pollution and energy conservation, the needs to introduce new recommendations for energy efficient lighting and new indicators to evaluate the energy performance of lighting systems are arisen. At the beginning, the attention was paid to the indoor lighting systems [17], [18], [19], [20], [21], [22], nowadays new efforts are focused on the energy consumptions of public lighting systems [8], [11], [25] and some energy performance indicators have been proposed at international level to compare the performance of these systems [23].

In Europe, only few countries have provisions addressing the energy efficiency of the road lighting systems. In Ref. [8], useful suggestions for preparing such provisions were supplied, identifying a set of the most important recommendations regarding the influencing factors for energy savings in road lighting. However the suggestions were mainly qualitative and there was no systematic use of energy-based and lighting-based parameters for the comparison of different road lighting systems. In the Netherlands an energy efficiency A-G label were developed for road lighting systems, based on the Street Lighting Energy Efficiency Criterion (SLEEC), which is a whole system indicator taking into account efficiency of the lamp, ballast and luminaires [24]. In Ref. [25] a multi-objective evolutionary algorithms was presented with the aim to use it for planning efficient public lighting. The approach adopted in Ref. [25] was SLEEC-based, but no result about other performance indicators were shown, thus the work does not contribute to a critical comparison between the different performance indicators proposed at international level. In Italy, the legislative power in matter of light pollution, design and management of public lighting belongs to the Regions that can enact laws applicable in its territory [26], [27]. In Ref. [11] a new interesting methodology for the evaluation of the cost-benefit ratio, for energy saving interventions on the road lighting, was proposed by using the case study of the Comiso Municipality (Italy). In the case study, a comparison between 2 different scenarios (providing specific energy efficiency measures) was made, but also in this work the techno-economic analysis does not use the performance indicators proposed at international level. In this context, it is clear the importance to critically discuss and compare the energy performance indicators for road lighting systems, currently available at international and national (Italian) level.

In this paper the Authors propose a critical analysis of the most significant numeric indicators for the evaluation of lighting and energy performance of both new-designed and existing (whose refurbishment is to be planned) road lighting systems. The comparison of energy performance indicator takes into consideration the types of lighting systems (new-designed or existing under refurbishment) and it is aimed to:

  • define strengths and weaknesses of each indicator,

  • provide suggestions on the use of the appropriate indicators during the design stage of road lighting systems.

These aspects are not sufficiently clarified by the technical standards and nor by the scientific literature. To support the discussion, the use of the case study of the road lighting of the historical old town center of Pisa is proposed. In order to analyze the current state of the road lighting systems of the case study, the Authors have defined an investigation procedure that has been applied to a sample of 20 roads, representative of 80 similar roads. The use of the case study is not be intended as a limitation of the performed research, but as an application example of the investigation procedure defined by the Authors, useful in highlighting the critical issues about the evaluation of energy performance indicators, especially for existing public lighting systems. The same approach followed by the Authors, in fact, could be used in any other town. Moreover, being the state of the art of public lighting in the historical towns of central Italy (often characterized by similar lighting infrastructure, similar lamps and luminaires typologies), the use of Pisa as case study town can be considered representative for a large number of historical towns located in that geographical area.

Section snippets

Energy performance indicators for road lighting

Recently, with the aim to quantify the potential savings obtainable from the improvement of the energy performance of the road lighting systems, some numerical indicators have been introduced on European and Italian levels. The most important energy performance indicators for road lighting systems are summarized in Table 1, and briefly discussed in the Annex B.

In the European standard [23], the Power Density Indicator and the Annual Energy Consumption Indicator have been defined. The Power

Analysis of the energy performance of urban lighting systems: the case study of Pisa

The city of Pisa originated as an Etruscan river port around the middle of the sixth century, even though the presence of definite clusters of dwellings was documented around the ninth century [32], [33]. Pisa is located few kilometers from the Arno river mouth on the Tyrrhenian Sea and is considered to be one of the most important art cities in Europe [33]. The city covers an area of 185.2 km2; the oldest part of Pisa lies within its Medieval walls and is centrally located, whereas modern

Calculation and discussion of energy performance indicators

The energy performance indicators DP and DE specified in Ref. [23] and the energy performance indicators IPEA and IPEI specified in Ref. [31] have been calculated for the analyzed roads.

For calculating DP it has been necessary to identify the areas which make up the chosen typical span (sidewalk and carriageway) and to refer to the calculated average illuminance (see Table 5, Table 6). For calculating DE an operating time of 4000 h has been assumed with a single utilization profile in the

Conclusive remarks

From the detailed analysis conducted on the different performance indicators and from their application to the case study of the historical town of Pisa, the following considerations can be outlined for each studied indicator. Although deducted from the case study of Pisa, the following considerations are obtained with an investigation procedure of general validity and they can be extended to other towns, with particular reference to the historical towns of central Italy, whose road and

References (39)

  • V.R.M. Lo Verso et al.

    A multivariate non-linear regression model to predict the energy demand for lighting in rooms with different architectural features and lighting control systems

    Energy Build

    (2014)
  • O. Rabaza et al.

    A simple method for designing efficient public lighting. based on new parameters relationships

    Expert Syst Appl

    (2013)
  • Committee to local sustainable energy

    Covenant of majors: how to develop a sustainable energy action plan (SEAP). - Guidebook

    (2010)
  • L. Cellucci et al.

    Urban lighting project for a small town: comparing citizens and authority benefits

    Sustainability

    (2015)
  • I.O. Mokey Coureaux et al.

    The energy impact of luminaire depreciation on urban lighting

    Energy Sustain Dev

    (2013)
  • L. Tahkamo et al.

    Life cycle assessment of road lighting luminaires - comparison of light-emitting diode and high-pressure sodium technologies

    J Clean Prod

    (2016)
  • Giuliani G., Gozo N., Honorati Consonni C., Meloni C., Pollidori R., Annunziato M. "The Lumière project", Project of...
  • S. Onaygil et al.

    Cost Analyses of LED luminaires in road lighting

    Light Eng

    (2012)
  • P. De Bernardis et al.

    The urban lighting in the rehabilitation of the minor historical centre. The design scenarios for the architectural valorisation and the energy efficiency improvement of the urban environment

    Vitruvio Int J Archit Technol Sustain

    (2015)
  • Cited by (31)

    • A new approach to calculating energy performance indicators of road lighting

      2021, Sustainable Cities and Society
      Citation Excerpt :

      Therefore, it is possible to state with certainty that active, reactive and distortion power flows in the road lighting installation. All energy efficiency indicators of road lighting described in literature (Yoomak & Ngaopitakkul, 2018, Lecce et al., 2017, Rabaza et al., 2013, Kyba et al., 2014, EN 13201-5 2015) only take into account active power. In this way, the impact of reactive and distortion power flow and their obvious influence on energy efficiency have been ignored.

    • A decision-making tool for transition towards efficient lighting in a context of safeguarding of cultural heritage in support of the 2030 agenda

      2021, Journal of Cleaner Production
      Citation Excerpt :

      It certainly involves high initial investments but allows achievement of short-term efficiency and profitability, as well as long-term sustainability. Leccese et al. (2017) analysed a case study of the historic centre of Pisa (Italy), in 2015, where approximately 13,000 existing luminaires were replaced with new LED technology to promote energy saving. Other authors illustrate methodologies and intervention strategies for the requalification of lighting scenarios in Italian historical contexts (Cellucci et al., 2015; Cucchiella et al., 2017; Demiröz and Acarkan, 2016; Valetti et al., 2021).

    • Cement filled with phosphorescent materials for pavement: Afterglow decay mechanism and properties

      2021, Construction and Building Materials
      Citation Excerpt :

      Due to the rapid increase of energy consumption [1], improving energy utilization efficiency will contribute to energy conservation and construction of low-carbon eco-friendly environment [2–5].

    • Intelligent control and energy saving evaluation of highway tunnel lighting: Based on three-dimensional simulation and long short-term memory optimization algorithm

      2021, Tunnelling and Underground Space Technology
      Citation Excerpt :

      Some energy performance indicators have been proposed internationally to compare these systems (European Committee for Standardization, 2015). Calculating and comparing each indicator (Leccese et al., 2017) have a guiding effect on using these indicators appropriately. The rationality of these evaluation methods has been verified in Italy, Pisa, and other places.

    View all citing articles on Scopus
    View full text