Comparative analysis of concentrating solar power and photovoltaic technologies: Technical and environmental evaluations

Solar energy is an important alternative energy source to fossil fuels and theoretically the most available energy source on the earth. Solar energy can be converted into electric energy by using two different processes: by means of thermodynamic cycles and the photovoltaic conversion. Solar thermal technologies, sometimes called thermodynamic solar technologies, operating at medium (about 500 degrees C) and high temperatures (about 1000 degrees C), have recently attracted a renewed interest and have become one of the most promising alternatives in the field of solar energy utilization. Photovoltaic conversion is very interesting, although still quite expensive, because of the absence of moving components and the reduced operating and management costs. The main objectives of the present work are: to carry out comparative technical evaluations on the amount of electricity produced by two hypothetical plants, located on the same site, for which a preliminary design was made: a solar thermal power plant with parabolic trough collectors and a photovoltaic plant with a single-axis tracking system; to carry out a comparative analysis of the environmental impact derived from the processes of electricity generation during the whole life cycle of the two hypothetical power plants. First a technical comparison between the two plants was made assuming that they have the same nominal electric power and then the same total covered surface. The methodology chosen to evaluate the environmental impact associated with the power plants is the Life Cycle Assessment (LCA). It allows to analyze all the phases of the life cycle of the plants, from the extraction of raw materials until their disposal, following the "from cradle to grave" perspective. The environmental impact of the two power plants was simulated by using the software SimaPro 7.1, elaborated by PRe Consultants and using the Eco-Indicator 99 methodology. Finally, the results of the analysis of the environmental impact are used to calculate the following parameters associated to the power plants: EPBT (Energy Pay-Back Time), CO2 emissions and GWP100 (Global Warming Potential over a 100 year time horizon). (c) 2012 Elsevier Ltd. All rights reserved.