SPI Insights

CPS Energy, a San Antonio-owned utility, recently announced a 15-year partnership with a private Houston-based start-up to use water pumped underground as a battery to store power in reserve to be used during hot days and other times of peak demand.

Using hydraulic fracturing technology, typically employed by the oil and gas industry, water is pumped into rock deep underground where it is stored at high pressure. This water can be released to spin a turbine and generate zero-carbon electricity.

The partners will start with the development of a facility that can store 1 megawatt (MW) of power in the project’s first phase.

With renewable energy being inconsistent at times, CPS has sought to expand energy storage as it shifts away from fossil fuels. This system could alleviate the inconsistency of wind and solar energy by offering power at any time.

CPS currently operates a 10MW battery system that can only store energy for up to an hour. Through its FlexPower Bundle initiative, CPS plans to add another 50MW. This energy storage will help provide energy during peak demand times without CPS shopping for electricity on the wholesale power market.

CPS began soliciting offers from developers to build solar farms and battery arrays over a year ago in order to expand energy storage capacities around the city and meet its green energy goals.