Those plants concentrate the solar irradiation thanks to mirrors to heat a fluid up to high temperatures (oil, steam) which is then transferred to a turbine to produce electricity. As any electrical production means from heat, preservation of the turbine efficiency depends on the presence of an abundant cooling source, usually water. The availability of this cooling water is a critical challenge for CSP plants located in highly insulated and so arid areas.

The SOLWATT project has started in May 2018. It gathers 13 European and Israeli partners with a global budget of 12 M€ for a 4-year period.  Innovative solutions are to be pushed to a high maturity level to be implemented on the industrial sites of the LA Africana Power Plant, located in Seville, Spain and the ASHALIM Power Plant in Israel. 
The challenge is to significantly reduce the water consumed by CSP plants while maintaining their efficiency. Those innovations deal with the reduction of the water needs for the solar field cleaning and for the turbine cooling, with the recycling of the make-up water, and with the optimization of the operation and maintenance on the plant.

In most of the CSP plants, the cooling of the turbine is realized through wet coolers as cooling towers. Dry coolers (consuming no water) exist, but their efficiency under hot ambient is significantly lowered. 

In the frame of the SOLWATT project, CEA LITEN has the responsibility to develop a cooling system for the turbine condenser thanks to a dedicated «cold storage» system. It enables the partial storage of the heat exhausted by the turbine during the day (when the external temperature is too hot for maintaining a good cooling efficiency). Its refreshment is performed during the night when ambient is lower.

Solutions developed within the project are highly replicable for any other electrical production system subject to high ambient with low water resources available: gas turbines, combined cycles.

SOLWATT objectives and technologies to reduce water consumption in CSP plants: