Abstract: An underwater pumped storage power plant that includes: an accumulator system with pressure vessels fillable with water and; a water outlet for water flow out of the system into a surrounding ocean against hydrostatic water pressure (PT) corresponding to water depth (T); a pump at the water outlet to pump water out of the system by converting electrical energy into potential energy corresponding to a displaced water column PT; a water inlet to allow water flow into the system from the surrounding ocean; a common generator at the water inlet, to convert the potential energy back into electrical energy when water flows in; electric lines to transport the electrical energy from the ocean surface to the power plant and back, wherein the pressure vessels are pressure-resistant and resistant to deformation from the PT at the ocean floor.