1991 – A 110 megawatt plant with a capacity of 26 hours was built in McIntosh, Alabama (1991). The Alabama facility's $65 million cost works out to $550 per Kilowatt hour of capacity, using a 19 million cubic foot solution mined salt cavern to store air at up to 1100 psi. Although the compression phase is approximately 82% efficient, the expansion phase requires combustion of natural gas at one third the rate of a gas turbine producing the same amount of electricity
Last week, Bill Gates mentioned that he’s involved with an energy storage company that was basically “gravel on ski lifts” at the Economics Conference organized by the Wall Street Journal. (Thank you, Katie Fehrenbacher, for attending.) (See video, minutes 19:15 to 20:10).
Ski lift storage has been one of those topics discussed in the hallways of energy storage conferences for years. Someone was out there, the conversation went, that wanted to use a solar- or wind-powered ski lift apparatus as a pump. It would pump gravel or water up a hill during sunny periods. At night or during peak power emergencies, the gravel or water could be released. The system essentially artificially supplies the elevation that nature left out.
