Renewables

ERCOT could get its first geothermal project

Sage Geosystems has entered into a land use agreement with San Miguel Electric Cooperative for a 3 MW geothermal facility.
ERCOT could get its first geothermal project
(Source: Sage Geosystems.)

Sage Geosystems (Sage), a geothermal baseload and energy storage company, announced the location of its “first-of-its-kind” project, which would be the first geothermal project in Electric Reliability Council of Texas (ERCOT) territory.

Sage has entered into a land use agreement with San Miguel Electric Cooperative Inc. (SMECI) for the 3 MW Geopressured Geothermal System (GGS) energy storage facility. The 3 MW EarthStore system will be in Christine, Texas near the SMECI lignite coal power plant. Sage will operate as a merchant, buying and selling electricity to the ERCOT grid.

Later this year, Sage will launch the EarthStore facility, which it says will utilize the earth’s “natural capacity for energy storage” to produce dispatchable electricity on demand through a power source that works independent of weather conditions.

“Once operational, our EarthStore facility in Christine will be the first geothermal energy storage system to store potential energy deep in the earth and supply electrons to a power grid,” said Cindy Taff, CEO of Sage Geosystems. “Geothermal energy storage is a viable solution for long-duration storage and an alternative for short-duration lithium-ion batteries. Electric utilities and co-ops like SMECI, will be able to use our technology to complement wind and solar, and stabilize the grid.”

The facility will use Sage’s proprietary technology to store energy, targeting 6-to-10-hour storage durations and delivering a round-trip efficiency (RTE) of 70-75%, Sage said. In addition, water losses are targeted to be less than 2%. At scale, this energy storage system will be paired with renewable energy to provide baseload and dispatchable power to the electric grid. When combined with solar power, Sage’s EarthStore facility enables 24/7 electricity generation at a blended Levelized Cost of Energy (LCOE) well under $0.10/kWh, it said.

“Long-duration energy storage is crucial for the ERCOT utility grid, especially with the increasing integration of intermittent wind and solar power generation,” said Craig Courter, CEO, San Miguel Electric Cooperative. “We are excited to be part of this innovative project that showcases the potential of geothermal energy storage.”

Sage will be applying for two drilling permits in Texas. The first permit is in Atascosa County for the EarthStore facility in Christine and the second permit is in Starr County, adjacent to the company’s existing test well.

Geothermal electricity generation taps high-energy-content steam at temperatures of 300-700 degrees Fahrenheit and requires drilling to depths that are as much as tens of thousands of feet below the surface.

The process works by drilling sets of both injection wells and production wells. Cold water is pumped down the injection well and then flows through the geothermal reservoir to the production well. The water returns to the surface at a high enough temperature for the energy to be captured at the surface and enter an electric generation cycle.

GO DEEPER: Fervo Energy co-founder and CEO Tim Latimer joined the Texas Power Podcast with Doug Lewin to discuss a hoped-for resurgence in the geothermal energy industry. Subscribe wherever you get your podcasts.

Compared to older, traditional geothermal energy sites, it’s much more challenging, and expensive, to find heat resources suitable for electricity generation today. That’s why companies like Fervo Energy and Sage are incorporating techniques from the oil and gas industry to give the geothermal industry new life.

Although Texas doesn’t have any geothermal projects of its own yet, several companies headquartered in Houston, including Fervo Energy and Sage, are hoping to change that. Some former oil and gas industry professionals are now championing geothermal as a new resource for reliability, especially given the crossover between equipment and techniques from the oil drilling industry, the Texas Tribune reports.