Comparative cradle-to-grave life cycle assessment of traditional grid-connected and solar stand-alone street light systems: a case study for rural areas in Lebanon

Abstract

Nocturnal lighting systems account for 20% of the total global electricity consumption. The aim of this paper is to investigate and compare the following two street lighting technologies in Lebanon from an environmental perspective: i) traditional grid-connected system and ii) solar stand-alone system. Life Cycle Assessment (LCA) is the methodology used to assess and compare the potential environmental impacts of the two systems from cradle-to-grave, i.e. from the raw material extraction until the end-of-life product stages. Two end-of-life scenarios are modeled: landfilling and recycling. The SimaPro software is used for modeling the Life Cycle Inventory and the IMPACT 2002 + method is used for the Life Cycle Impact Assessment. The traditional system includes a steel pole, a High-Pressure Sodium lamp, and aluminum cables. The stand-alone solar system includes a steel pole, a Light Emitting Diode lamp, a photovoltaic panel, a valve regulated acid battery, a controller, a dimmer, and copper cables. Results show that the traditional system has less environmental impacts than the solar stand-alone system when considering the life cycle stages from the raw material extraction to the production phase only. This is mainly due to the important environmental impacts of the lead and electronics used in the solar system. However, this difference is compensated during the entire life cycle from the raw material extraction to the end-of-life because the traditional system consumes a significant amount of energy from the Lebanese electricity grid during the use phase. The grid mostly relies on thermal power plants, imported fuel, and diesel generators. The results show that the solar system has less overall environmental impacts than the traditional system for both landfilling and recycling scenarios. In particular, it is shown that the recycling scenario for the solar system results in positive impacts on the environment.