Note to players: Description acceptable. One technology for this purpose has an “advanced adiabatic” variant that has yet to achieve viability. Various devices that serve this purpose can be compared using a Ragone plot. One type of device used (-5[1])for this purpose relies on the formation of a double layer on two coatings of activated carbon and is called an EDLC. Another system for this purpose uses magnetic bearings to levitate a (*) flywheel. Round-trip efficiencies between 70-80% are achieved by “pumped” systems for this purpose, which hold water at two different elevations to deal with load fluctuations. Technologies for this purpose are needed because, for many renewables, peak demand and peak production occur at different (10[1])times. For 10 points, name this process performed by hooking up a power plant to a grid of rechargeable batteries. ■END■ (10[1])