Carbon-Pros Analyst Blog

Like pumped hydro, CAES converts electricity into potential energy that can be drawn on when needed. During charging, off-peak, low-cost electricity is used to pump high-pressure air into an underground cavern such as a salt dome. The air is held under pressures between 1,000 and 1,500 pounds per square inch (PSI). By comparison, scuba tanks hold air at about 3,000 PSI. During discharging, plant operators bring air from the cavern back to the surface, where it is heated with natural gas, causing it to expand and rush through combustion turbines that power a generator. CAES in not solely a storage system. It is a hybrid technology that uses the compressed air to turbocharge a highly efficient natural gas turbine. The waste heat rate of a CAES plant is roughly half that of a traditional natural gas plant. The electricity created by the CAES generator can be delivered to customers at peak periods through the utility transmission and distribution network.