Storage of Renewable Energies Focus: Thermal energy storage for CSP plants

Kurzfassung

Currently the major supply of renewable electricity (apart from hydropower) comes from Wind (>200 GW installed worldwide) and Photovoltaic (PV, >100 GW installed worldwide). In some electric grid there annual share is already about 20%, and strong cost reductions have been achieved. However the supply of electricity from wind or PV plants is intermittent and not necessarily matching demand, it is not dispatchable. This increases the need for electricity storage technologies and growing R&D activities are dedicated to improve current electricity storage technologies, to increase total capacity and decrease cost. Concentrating solar power plants, that convert solar energy to electricity via thermal conversion offer the option to include low cost thermal storage systems to shift electricity generation to hours of higher demand and/or lack of sunshine. This dispatchability makes them a very important part in electric grids with high shares of fluctuating renewable energies. CSP thus can help enabling a higher share of fluctuating over renewable energies (see figure 1). This contribution will focus on the current state of art of thermal storage technologies for concentrating solar power (CSP) Plants and include an overview on other current electricity storage technologies.