Cradle-to-grave environmental life cycle assessment of a thermal solar system : a case study for a Jordanian industrial facility

Abstract

Renewable energy is an endless supply of energy originating from natural sources that can help reduce the carbon footprint and increase the energy supply of the planet. The global power generated by solar thermal energy is estimated to increase from 115 GW to 130 GW by 2024. Thermal solar systems are used in order to concentrate the energy from the sun and convert it into electricity and heat. This study aims to determine and analyze the environmental impacts of a thermal solar system, more specifically the linear Fresnel collector (LFC). Impacts are compared to the ones resulting from the use of a traditional boiler system. The LFC is implemented at a Jordanian company which needs around 396 MWh/year to operate; 80% of which are provided by the LFC and the remaining 20% by the traditional boiler which is used as backup. In this study, life cycle assessment is the methodology used to assess and analyze the potential environmental impacts of the energy systems from a cradle-to-grave approach, i.e. from the raw material extraction until the end-of-life. The SimaPro software is used to model the life cycle inventory and the IMPACT 2002+ method is used for the life cycle impact assessment. The LFC system includes two sets of 9 modules, each one made of a support structure with 22 mirrors and one receiver. There is also a connector connecting the two sets of modules, one storage tank, 10 valves, 2 pumps and 10 m of pipes. The fuel consumption used by the backup boiler is also considered, along with the transportation and end-of-life data. Results show that the LFC system offers several environmental benefits when compared with the traditional boiling system during the 25 years lifetime for 8 impact categories: non carcinogens, respiratory inorganics/organics, aquatic ecotoxicity/acidification, terrestrial acidification/nutrification, global warming and nonrenewable energy. However, it is still considered to have a high impact on the ecosystem quality due to the large amount of steel present in the system. This difference is compensated since the use of a boiling system consumes a significant amount of diesel. The results also show that the LFC system has less overall environmental impacts when recycling scenarios of steel are introduced, which makes the LFC system more environmentally friendly and less harmful for the resources and human health damage categories.