Pumped thermal electricity storage (PTES) systems have attracted increasing attention, owing to high energy density, low cost, flexible adjustable energy storage duration, and lack of geographical restrictions. At present, theoretical research for PTES is relatively deep. Further reduction of investment costs is of great value to its development and application. This paper proposes a 10-MW PTES system with indirect thermal energy storage (TES) (I-PTES). The I-PTES and a PTES system with direct TES (D-PTES) are analyzed and compared in terms of their technical and economic performances. The results show that the I-PTES is advantageous owing to its low installation cost when its electricity storage duration exceeds 6 h, despite bearing some loss in round-trip efficiency. For longer-duration electricity storage, the energy capital cost of I-PTES can be lower than 200 $/kWh, i.e., 40% lower than that of D-PTES, whereas the penalty for its round-trip efficiency can be less than 5% after optimization. For a 10-MW I-PTES system, the optimum round-trip efficiency and energy density can reach approximately 65% and 26 kWh/m³, respectively. This research provides a more economical choice for the long-duration electricity storage, and a theoretical basis for the design and optimization of high-efficiency and low-capital-cost PTES systems.

抽水蓄能（PTES）系统由于能量密度高、成本低、储能持续时间灵活可调以及不受地域限制等优点而受到越来越多的关注。目前，对 PTES 的理论研究比较深入。进一步降低投资成本对其开发应用具有重要价值。本文提出了一种具有间接热能储存 (TES) (I-PTES) 的 10 MW PTES 系统。对 I-PTES 和具有直接 TES (D-PTES) 的 PTES 系统的技术和经济性能进行了分析和比较。结果表明，尽管在往返效率上有一些损失，但 I-PTES 在其蓄电持续时间超过 6 h 时由于其安装成本低而具有优势。对于更长时间的电力储存，I-PTES 的能源资本成本可以低于 200 美元/kWh，即比 D-PTES 低 40%，而优化后其往返效率的损失可以低于 5%。对于 10 MW I-PTES 系统，最佳往返效率和能量密度可达到约 65% 和 26 kWh/m³、分别。该研究为长时储能提供了更经济的选择，为高效、低成本的PTES系统的设计和优化提供了理论依据。