A Low Cost, 3D Concrete Printed, Modular, Marine Pumped Hydroelectric Storage System

New long-duration energy storage is critical for the US to incorporate new renewable energy generation, increase system efficiency and resiliency, and reduce usage of fossil-fuel plants to meet periods of peak electric demand. Pumped hydroelectric energy storage is presently the dominant form of long-duration storage, supplying ~94% of US energy storage capacity due to its low cost, high round-trip efficiency, reliable operation, and long cycle lifetime. However, new deployments of conventional pumped hydro storage are limited by permitting challenges, geographic suitability, high costs, long development times, and other factors. The proposed marine pumped hydroelectric energy storage system is a long-duration storage technology that cycles pressurized water in and out of large (15–40 m diameter) spheres on the seafloor to release and store energy. It retains the benefits of conventional pumped hydro storage while sidestepping many of its constraints cutting project development time by up to 75%, reducing costs, and increasing gross technical storage resource potential up to 200-fold over conventional pumped hydro storage, all while offering the design and manufacturing benefits of modularity. The new technology creates local storage potential for communities or military bases located near large bodies of water and can integrate directly with offshore wind and wave generation synergistically enhancing their value by smoothing variable power output and offering new revenue and business model opportunities for developers. The Phase I project objectives are to analyze US commercial potential of marine pumped hydro, produce a manufacturable system design, and plan for manufacturing and wet testing of a sub-scale prototype in Phase II. Expected project deliverables include (1) a comprehensive analysis of the commercial potential as part of a hybrid wind and wave power plants, (2) detailed cost and performance metrics and estimates for a commercial marine pumped hydro storage plant and a conventional pumped hydro reference model, (3) detailed schematics of features and operating states, and (4) a Phase II prototype manufacturing, testing plan, and demonstration site. Using large-scale three dimensional concrete printing to reduce manufacturing cost, the disruptive storage technology can competitively provide much of the new long-duration storage that the US needs to meet or exceed its storage and renewable energy goals. It can also reduce imports of competing storage technologies and materials and create quality domestic jobs and economic benefits through manufacturing and maintenance in America’s ports. Marine pumped hydroelectric storage can be integrated with offshore renewable energy generators in small modular increments, opening up large new areas for pumped hydro storage within economic transmission range of coastal energy markets. Firming offshore wind and wave energy plant output with marine pumped hydro will increase its value, benefiting its developers and improving grid resilience and reliability at the high levels of renewable penetration that are urgently needed to decarbonize energy use. Near-term market entry will thus speed and help facilitate growth of offshore wind and wave energy markets. Co-locating energy storage with offshore wave and wind plants will provide the full spectrum of existing essential reliability services and new, evolving grid reliability services; for example, hybrid plants can provide self-black starts as well as power-system black starts, operate in islanded mode, and participate in power-system restoration schemes. Seafloor siting of marine pumped hydro is inherently robust against malice and natural disaster, and presents near-zero toxic hazard, being constructed almost entirely of steel and concrete and relying on air and seawater as its energy-storage media.