Huntorf compressed-air storage (1978)
Germany switched on the world's first commercial compressed-air energy storage plant at Huntorf, a 290 MW facility that pumped air into two salt caverns and burned natural gas to heat it during expansion.
Huntorf and one later US plant (McIntosh, Alabama, 1991) proved the concept but never scaled.
Only those two commercial compressed-air plants were ever built, because the technology needed underground salt caverns and burned fossil fuel.
Energy Dome's CO2 battery is the same idea — store energy as compressed gas — but closed-loop, cavern-free, and fuel-free.
