Test System for Underground Pumped Hydro

Almost 90% of the stationary electricity storage in the U.S. is pumped hydro, and a huge quantity of additional storage is required, but environmental and social constraints make it impossible for additional pumped hydro, in its current form, to be constructed fast enough to meet demand. Addressing the Problem: Gravity Power Inc. (GPI) is developing a large-scale electricity storage system, the ôGravity Power Plantö (GPP), which builds on the legacy of pumped hydro by using the same power equipment but replaces enormous surface reservoirs with an underground shaft and a hydraulically lifted mass. Land requirements drop from thousands of acres for conventional pumped hydro to less and ten acres for a GPP of similar capacity. Phase I: During Phase 1, GPI will (1) analyze the commercial potential of GPPs; (2) quantify the improvement provided by GPPs relative to existing storage technologies; (3) specify where and how GPPs can be deployed; (4) provide detailed schematics and descriptions of GPP features and operating states; (5) develop the detailed design of a GPP seal assembly at sufficient scale to validate performance in an environment closely approximating that of a commercial-scale GPP; and (6) develop the detailed design of an installation to test the operation and performance of key components of the GPP, with a particular focus on the hydraulic seals. This test facility will use a piston massing more than 100 tonnes and hydropower equipment to stress the seals in an environment closely approximating a commercial-scale GPP, including pressure, piston speed, and piston surface characteristics. Commercial Applications and Other Benefits: Phase II will use the designs created in Phase I to fabricate and test a seal assembly, resulting in a TRL 6 design ready for implementation in commercial-scale GPPs. Such GPPs will allow pumped hydro plants to be constructed almost anywhere high-capacity electricity storage is needed. They will transcend the limitations of PSH, surpass the Long Duration Storage Shot LCoS goal of 5¢/kWh before 2030, and radically reduce project development time and environmental impact.