Sage Geosystems, seeking to unlock energy storage with geothermal technology, is making progress on its commercial-scale energy storage facility in Texas. Sage plans to drill a well in June or July and commission the project by year’s end.

Located in Atascosa County, Texas, south of San Antonio, the 3-megawatt EarthStore energy storage project will be the first of its kind and part of the ERCOT South Load Zone of Texas. Its startup is expected to not only help bolster the reliability of the grid as more intermittent renewables come online. The project will also accelerate deployment of Sage’s geopressured geothermal system (GGS).

The technology collects energy from pressurized water stored underground for both short- and long-duration periods. That energy can be dispatched when needed to the grid.

“All of our equipment is ordered. We’re currently working on a land use agreement with the utility company,” Sage Geosystems CEO Cindy Taff told Hart Energy. She said the utility company hasn’t been named because an agreement is not yet finalized.

If all goes as planned, Sage expects to commission the facility, which it says will be the world’s first commercial GGS facility, in December.

However, the project will likely not interconnect to the grid until 2025.

“It takes several months to do a feasibility study, and then you have to order a meter and that takes [about] 50 weeks. So, it pushes you into 2025,” Taff said. She added, “We’re excited, of course, to get that first facility built and commissioned and actually show that we’re going to be generating electricity at utility scale.”

In 2023, Sage successfully demonstrated the EarthStore system as part of a full-scale commercial pilot project. Generating electricity with Pelton turbines, Sage said the pilot produced 200 kW for more than 18 hours (long-duration) and 1 megawatts for 30 minutes (load-following).

Sage, which counts Chesapeake Energy and Nabors among its investors, is also moving forward with additional projects involving the U.S. military as the nation looks to increase the renewable energy’s presence on U.S. electricity grids.

The company plans to reenter a well in Starr County, Texas, and carry out a geothermal demonstration for the U.S. Air Force. The work follows a feasibility study performed by Sage for the Air Force in 2022.

Using the Ellington Field Joint Reserve Base in Houston as its proving ground, the Air Force is evaluating the use of smaller geothermal systems to cost-effectively generate power on the base. It has potential for a wider deployment.

“The [Starr County] well can produce about 3 megawatts, but these micro facilities are going to be about 250 to 300 kW. So smaller electricity production,” Taff said. “What the Air Force wants to do is demonstrate that we can generate electricity, and they want to do it more quickly than having to wait two years to order a full scale 3-megawatt facility. So, we’re hoping to do that work the end of this year into next year.”

In addition, Sage was one of three geothermal companies—the others being Fervo Energy and GreenFire Energy—selected earlier this year to carry out next-generation geothermal feasibility studies for U.S. military installations. Fervo’s enhanced geothermal systems efforts are focused on the Naval Air Station Fallon in Nevada. GreenFire is exploring the use of its closed-loop technology at Naval Air Facility El Centro in California, while Sage is exploring use of its GGS technology at the Army’s Fort Bliss in Texas.

“The primary goal is to look at the geothermal potential for providing electricity generation to the base. So, the grant that we got—$600,000—was for a feasibility study,” Taff said. “If successful, the next step would be an environmental assessment.”

That could eventually lead to drilling a prototype well in a future phase, if funded.

Comments