New geothermal facility to be built

HOUSTON – A South Texas coal mine and coal-fired power plant will host a new geothermal energy storage facility as part of a local electric utility’s energy transition, according to the Houston Chronicle. Sage Geosystems, a Houston-based startup founded by former executives from Shell, first announced plans to build a 3 megawatt geothermal energy storage facility, capable of providing enough electricity to power 750 Texas homes on the hottest summer days, in February. The company said Tuesday that the project would be built in Christine, about an hour south of San Antonio. Sage has leased 10 acres for the facility from San Miguel Electric Cooperative, a utility that powers up to 78,200 South Texas homes, Sage CEO Cindy Taff said. The geothermal project will be on the same site as San Miguel’s coal mine and coal-fired power plant.

The project could be the first geothermal facility in Texas and comes as the state’s grid faces twin pressures from unprecedented power demand growth and extreme weather. Grid experts say energy storage systems can help stabilize the grid by providing electricity when it’s most needed and by storing excess renewable energy for use when the sun isn’t shining and the wind isn’t blowing. San Miguel CEO Craig Courter said the utility began to take an interest in geothermal energy, and in Sage Geosystems in particular, as it grappled with how to provide cleaner yet still affordable and reliable electricity to its customers in rural South Texas. San Miguel has faced lawsuits from local ranchers over water and soil pollution from the Christine mine. The coal-fired power plant and lignite coal mine are supposed to close in 2037. That end date could come sooner if cheap solar and wind power make it uneconomic to produce coal-fired power, or if federal regulations aiming to limit climate-warming emissions from coal-fired power plants are enacted, Courter said. “We have to be ready at any time between now and 2037 and have a game plan for how we are going to continue producing this power, and it doesn’t happen overnight,” he said.