Exergoeconomic analysis of a pumped heat electricity storage system based on a Joule/Brayton cycle

Abstract

The share of renewable energy sources in the German gross electrical energy production was rising from 3.6% in 1990 up to 40.2% in 2019. 1 Extrapolating the trend shown in Figure 1, higher shares of renewable energy sources can be expected in the future. Adopted in July 2016, the newest version of the Act on the Development of Renewable Energy Sources (Gesetz für den Ausbau Erneuerbarer Energien, EEG 2016) targets to rise the share of renewable energy sources in gross electrical energy consumption to 40% in 2025, 55% in 2035, and 80% in 2050. 2 The higher the share of renewables, the stronger is the impact of the volatility of renewable energy sources on the production of electrical energy. More and more frequently, this results in a mismatch between the electrical energy supply and its demand. To maintain stability in the grid, supply and demand of electrical energy have to be balanced, because the grid itself cannot store electrical energy. Up to a certain degree, balancing of supply and demand can be achieved by flexible operation of power plants and load balancing. However, to reach the targets of the EEG 2016, medium-to large-scale storage systems for electrical energy are required.Electrochemical accumulators have limitations in cyclic stability and require relatively large amounts of rare