Concentrated solar power and pumped thermal electricity storage – synergy effects and innovative hybrid plant layouts

Concentrated solar power and pumped thermal electricity storage – synergy effects and innovative hybrid plant layouts

Large-scale high-temperature thermal energy storage (TES) is of high interest due to its cost competitiveness. Currently, high-temperature TES is applied in state-of-the-art solar thermal power plants (also referred to as concentrated solar power – CSP – plants), where molten salts are used for the storage of solar energy in the form of sensible heat. Another promising area of application for high-temperature TES is pumped thermal electricity storage (PTES), where high-temperature heat pumps are used to store electricity in the form of heat. The created temperature difference between low-temperature TES and high-temperature TES is later on used to drive a conventional heat engine to generate electricity. The principal advantage of PTES is that the storage of thermal energy in large scale is cheaper than the storage of electricity in batteries. Furthermore, PTES does not have any geographic limitations, as opposed to pumped hydro storage. PTES is thus a promising solution for large-scale and cost effective electricity storage, which is crucial for stabilizing the electricity grid when dealing with a high share of not-dispatchable renewables.
As both technologies, CSP and PTES apply TES in a similar temperature range, there exists the possibility of combining the concept of PTES with the TES technology applied in CSP plants, or even designing a hybrid plant which integrates PTES and CSP, by sharing the thermal energy storage system and thus being more cost effective. The aim of the proposed research line is to evaluate different TES materials, to analyze different forms of heat storage (sensible, latent and chemical), and to explore synergy effects and innovative plant layouts integrating both technologies.