Sizable Energy develops offshore pumped hydro energy storage systems. Its patented technology uses a fixed reservoir on the ocean floor, a floating surface reservoir, connecting pipes, and reversible pump-turbines to move saturated sea salt brine for long-duration storage. The Milan, Italy-based startup has raised $8 million and is led by co-founders Manuele Aufiero (CEO), Carlo Fiorina, and Stefano Bernardi. It has conducted sea trials off Reggio Calabria, Italy.