Seaworthy concrete sphere anchors renewable energy storage test

Sources: Sperra, San Pedro, Calif.; CP staff

Sperra, developer of a subsea pumped storage hydropower (SPSH) concept based on 3D-printed concrete spheres, has secured a $4 million U.S. Department of Energy (DOE) Water Power Technologies Office grant to demonstrate a 10-meter diameter, 500kWh/600kWh unit off the southern California coast. Formerly known as RCAM Technologies, the company proposes hollow vessels placed on the seabed at 600- to 800-meter depths. When energy demand is low, specially engineered, submersible pumps empty the spheres. At peak power demand, water is allowed to flow back, turning the pumps into electricity-generating turbines.

Sperra and Pleuger envision respective 3D-printed concrete spheres and pump/turbine assemblies equal to the pressure and harsh environment 2,000 feet or more down. The concept is shown here with wind power infrastructure, to which Sperra also applies 3D-printed concrete elements.

The DOE commitment unlocks $3.7 million in German Ministry for Economic Affairs and Climate Action funding to support a parallel project under Germany’s Pleuger Industries GmbH, Hamburg pump manufacturer, and Fraunhofer Institute for Energy Economics and Energy System Technology, Kassel. The Sperra concept builds on the “Stored Energy in the Sea” work of Fraunhofer, Professor Horst Schmidt-Böcking and Dr. Gerhard Luther, plus California Sustainable Energy Entrepreneur Development and New York State Energy Research and Development Authority undertakings.

“SPSH is an innovative technology that creates new deployment opportunities by storing energy out of sight in the ocean, near America’s largest cities. It provides the same benefits as traditional pumped storage hydropower but avoids many land-based challenges. A strong alternative to batteries, it does not rely on the critical materials needed for battery production and can largely be manufactured with locally sourced concrete,” Sperra notes.

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