Abstract: An improved electric power regeneration system, featuring reduced environmental air and thermal pollution. The system employs a method and means whereby during periods of low load demands upon a conventional type electric power generating plant, the excess power then available is employed (at low cost to the system) to pump low temperature ambient air (or any other suitably heat-absorbent gas) at relatively low pressure into a subterranean cavity in a salt deposit which is in thermal communication via an interconnecting spire or dome of salt with a geological "mother bed" occurring at such depths below the earth's surface as to constitute a constant high heat source. The air/gas conduit system is intermittently closed, whereupon the heat intake from the earth's center causes significant storage of heat energy in the entrapped air/gas and substantial increases of the pressures under which it is entrapped.