Power Play explores the critical role of LDES in enabling the clean energy transition by addressing renewable energy intermittency. It evaluates mechanical, electrochemical, thermal, and chemical storage systems, identifying technological advancements, barriers to commercialization, and global competitive dynamics. While the U.S. has made strides through funding initiatives like the DOE’s pilot programs, the PRC leads in LDES innovation and deployment due to state-backed investments and market control in key supply chains. The report emphasizes the importance of reforming energy markets, incentivizing adoption, and fostering international collaboration to scale LDES, reduce reliance on lithium-ion batteries, and accelerate decarbonization. Drawing on insights from 41 interviews, the study provides a strategic roadmap for the U.S. and allies to lead in LDES development, ensuring energy security and mitigating geopolitical risks.