Techno-economic evaluation of a Brayton Battery configuration with Power-to-Heat extension

Kurzfassung

The development of cost-efficient, environmentally friendly, and reliable technologies for utility-scale electricity storage is a key element for future flexible power systems. Brayton cycle-based Pumped Thermal Energy Storage (PTES) offers the potential of making a substantial progress to reach this goal. For further improvements in cost efficiency and flexibility we investigate the additional integration of Power-to-Heat (PtH) into the heat pump cycle. This integration allows a reduction in component size due to higher energy density; however, it also leads to efficiency losses. The objective of this paper is to quantify this tradeoff between round-trip efficiency and cost efficiency for closed-cycle Joule-Brayton PTES configurations and to provide design solutions for the novel PtH component. To this end, a wide-range design study with variable electric heating power and component efficiencies is conducted. In addition to the thermodynamic analysis, an economic assessment is presented, which clarifies the benefits of PtH extension. The results show a significant reduction of specific capital costs by up to 23%, along with higher system flexibility and a loss in round-trip efficiency of up to 5%.