Water consumption in solar parabolic trough plants: review and analysis of the southern Spain case

The purpose of this paper is to highlight water consumption as a key design parameter in determining the most convenient cooling system and selecting the most appropriate location for Solar Parabolic Trough (SPT) plants. Considering the importance of water in guaranteeing environmental sustainability, a review of water consumption parameters is presented, and water consumption in the SPT plants that are in the planning stages for southern Spain are analyzed as examples. The selected region for the present study, is exposed to high horizontal solar irradiance, undergoes large seasonal weather fluctuations (prolonged droughts) and is located far from the coast (determining the site׳s topography and soil availability). These characteristics demonstrate that water consumption is one of the decisive factors for the construction of new solar plants in similar locations worldwide, in addition to other considerations such as capital cost or plant efficiency. Currently, most SPT plants are based on the Rankine cycle via a conventional steam turbine generator, which implies the requirement of a cooling system using water. In this paper, all current cooling technologies are reviewed and the required water consumption is analyzed. The impact of plant consumption on the area of SPT plant location is analyzed as well. This paper also discusses the socio-economics and environmental effects of an implemented cooling system. In addition, this paper presents different technical alternatives for minimizing water consumption for cooling and the effects thereof on the rest of the key parameters in the development and construction of a new SPT plant.