The German-based Fraunhofer Institute for Energy Economics and Energy Systems Technology (IEE) designed this novel ocean battery, which can store energy and then release it as needed. Giant concrete spheres anchored to the ocean floor are an innovative approach to the world’s increasing energy needs. Expected to be active by the end of 2026, this project aims to demonstrate the feasibility of concrete sphere technology in real ocean conditions. The 3D-printed concrete spheres need to stand up to the massive water pressure at these depths. That means StEnSea systems could one day power nearly 75 million homes per year, enabling a vastly expanded energy storage solution.