Comparative life cycle assessment for traditional grid-connected high pressure sodium and solar stand-alone led street light systems : a case study for rural areas in lebanon

Abstract

Nocturnal lighting systems consume a significant amount of electricity in the world, accounting for 20% of the total global electricity. This consumption accounts for a considerable amount of Greenhouse Gases (GHGs) emissions (about 1900 Megaton (Mt) of CO2 per year). In addition, in Lebanon, most of the rural areas lack an effective road lighting system, due to power outages. With the recent implementations of the stand-alone solar system (SS) instead of the grid connected traditional system (TS), the aim of this study is to investigate and compare the potential environmental impacts of these two street light technologies. Lebanon has a good solar energy potential for 300 days per year with a daily insolation of 4.8 kWh/m2 . However, it is not benefiting from this source energy as it should, since the total renewable energy share including both the PV and hydro percentages does not exceed a value of 4.1% of the total annual electricity generation by "Electricité du Liban" (EDL), which puts Lebanon in a status far from sustainability while it has committed itself to shifting into a more sustainable development to reach a percentage of 12% by 2020 according to the National Energy Efficiency Plan (NEEAP). In this study, the Life Cycle Assessment (LCA) is the methodology used to assess and compare the potential environmental impacts of the two street light systems from cradle-tograve, i.e. from the raw material extraction until the end-of-life. 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, an HPS lamp, and aluminum cables. The stand-alone solar system includes a steel pole, a LED lamp, a PV panel, a valve regulated acid (VRLA) battery, a controller, a dimmer, and copper cables. Results show that the traditional system has less environmental impacts than the solar standalone system during the production phase. This is mainly due to the important environmental impacts of the lead and electronics used in the solar system (SS). However, this difference is compensated during the entire Life Cycle because the HPS system consumes a significant amount of energy from the Lebanese electricity grid. The latter mostly relies on thermal power plants, imported fuel, and diesel generators. The results show that the LED system has less overall environmental impacts than the HPS system with both landfilling and recycling scenarios. The difference is even larger for the LCA with recycling scenario making the solar system (SS) more environmentally friendly and less harmful for the human health than the traditional system (TS).