Thermal Storage Power Plants (TSPP) - Operation modes for flexible renewable power supply

Abstract

The paper at hand presents a simulation model for Thermal Storage Power Plants (TSPP). Such plants can theoretically cover highly variable residual load patterns during the transition from fossil to renewable electricity supply. TSPP can use electricity surplus from the grid, photovoltaic power and biomass or – during transition – natural gas as primary energy sources in order to generate highly flexible power just on demand. The core of a TSPP is a Carnot Battery consistent of an electric heater, a large-scale high-temperature heat storage and a Rankine power cycle. Gas turbines with waste heat recovery can be added for occasional peak loads that exceed the capacity of the steam turbine.After a brief introduction that explains the challenges of the energy transition that can be tackled by TSPP, the paper describes basic configurations and operation modes and the equations and parameters of the simulation model used for this analysis. After that, the feasibility of TSPP is tested for different configurations by modelling their technical and economical performance in the frame of highly variable residual load patterns derived from a 90% renewable electricity scenario in Germany. Finally, the results of this analysis and an outlook for further work are discussed.