Sperra, Fraunhofer IEE and PLEUGER Join Forces to Advance Subsea Energy Storage with Funding from US and German Governments

Sperra, a company dedicated to pioneering the next generation of renewable energy solutions through automated construction, has been awarded a $4 million grant from the U.S. Department of Energy Water Power Technologies Office to advance innovation in pumped storage hydropower technologies. In this project, Sperra will design, fabricate, and test a 10-m diameter, 500 kW / 600 kWh energy storage unit off the coast of Southern California. Additionally, this funding unlocks $3.7 million (€3.4M) from the German Ministry for Economic Affairs and Climate Action (BMWK) in the form of a parallel pump and turbine development project run by Fraunhofer IEE and PLEUGER Industries GmbH. The collaborative work of both projects will develop a low-cost subsea energy storage technology that supports electrical grid decarbonization.

New long-duration energy storage is essential for the US to integrate more renewable energy, improve grid reliability, and reduce fossil fuel usage during peak demand. Subsea pumped storage hydropower (SPSH) is an innovative technology that creates new opportunities for deployment of pumped storage hydropower by storing energy out of sight in the ocean, near America's largest cities.

SPSH provides the same benefits as traditional pumped storage hydropower but avoids many of the land-based challenges. This technology is a strong alternative to batteries because it does not rely on the critical materials needed for battery production and can largely be manufactured with locally-sourced concrete. The US has a vast potential for SPSH, with approximately 75 terawatt-hours of unused offshore potential, which is more than twice the potential of onshore closed-loop pumped storage.

"This project is a major step forward to realizing the full potential of energy storage to decarbonize our electric grid," said Jason Cotrell, CEO and Founder of Sperra. "SPSH with 3D-printed concrete will accelerate the energy transition, employing local labor and using immediately available materials. We are very excited about the international collaboration on this project with Fraunhofer IEE and PLEUGER, and are grateful that the Water Power Technologies Office recognizes the tremendous potential of this work."

Sperra's approach will advance the current state of the art in offshore energy storage by leveraging 3D printing to accelerate the deployment of concrete, modular and scalable energy storage solutions. It will build upon the pioneering work of Prof. Horst Schmidt-Böcking, Dr. Gerhard Luther, and Fraunhofer IEE on a subsea energy storage technology called "Stored Energy in the Sea" (StEnSea).

The project team includes world-leading research, engineering, and energy supply chain members necessary to complete the project and commercialize SPSH for US wind energy deployments including Sperra, WSP USA, Purdue University, the National Renewable Energy Laboratory, PLEUGER Industries GmbH, and Fraunhofer IEE. The team also includes a project advisory panel of key stakeholders.

"Pumped storage power plants are particularly suitable for storing electricity for several hours to a few days. However, their expansion potential is severely limited worldwide. Therefore, we are transferring their functional principle to the seabed – the natural and ecological restrictions are far lower there. In addition, the acceptance of the citizens is likely to be significantly higher," explains Dr. Bernhard Ernst, Senior Project Manager at Fraunhofer IEE.

This project builds upon R&D funding provided by the California Sustainable Energy Entrepreneur Development (CalSEED) program and the New York State Energy Research and Development Authority (NYSERDA). Future steps for Sperra include planning a grid-connected pilot demonstration to occur after the project's completion. This demonstration will help to de-risk the innovative technology and attract larger amounts of public and private funding for scaling up widespread deployments, providing a major contribution to the required energy storage capacity for the energy system of the future.

Sperra | sperra.com

Fraunhofer IEE | https://www.iee.fraunhofer.de/en.html

PLEUGER Industries | https://www.pleugerindustries.com/en/

U.S. Department of Energy Water Power Technologies Office | energy.gov/eere/water/water-power-technologies-office