W.M. Taggart IV
Cavern Energy Storage, LLC,
United States
Keywords: energy storage, long duration energy storage, LDES, pumped storage hydroelectric
Summary:
To support increased levels of variable renewable energy sources, long duration energy storage is required to reduce the volatility and match energy supply with consumer demand. Pumped storage hydroelectric is the majority of long duration energy storage, both in the United States and worldwide, but areas of the US, like Texas, Louisiana, and Mississippi, are too flat to use pumped storage. The solution is to combine pumped storage hydroelectric with salt dome caverns to provide long duration energy storage to Texas. Salt dome caverns have been in use for storing oil, natural gas, and other fluids and the construction and operation of these caverns is a proven technology. By constructing caverns at different elevations within the salt dome and pressurizing them with compressed air, those caverns can function just like the existing reservoirs in a pumped storage hydroelectric facility. There are 178 salt domes in Texas, Louisiana, and Mississippi, and enough undeveloped easily accessible acreage has been identified where 50,000 megawatts of up to 20-hour storage can be developed. This would supply most of the long duration energy storage needed by the 25 million Americans that live in the region. Long-duration energy storage enhances grid reliability and resilience by acting as an energy warehouse between variable renewable energy sources (wind/solar) and consumer demand. It also works with existing natural gas power plants allowing them to operate more efficiently and produce less pollution.