Sage Geosystems Selects Site of Geopressured Geothermal Energy Storage Facility

Sage Geosystems Inc. (Sage) signed a land-use agreement with San Miguel Electric Cooperative (SMECI) for its 3-MW GGS energy storage facility. The EarthStore system is sited in Christine, TX, near SMECI’s lignite coal power plant, with Sage purchasing and selling electricity to the ERCOT grid.

“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 project that showcases the potential of geothermal energy storage.”

GGS will leverage Sage’s technology to store energy for 6-to-10-hour durations with an RTE of 70-75% and water losses less than 2%. The energy storage system will be paired with renewable energy, providing baseload, dispatchable power to the electric grid. The EarthStore facility, when coupled with solar power, enables continuous electricity generation at a blended levelized cost of energy under $0.10/kWh.

Sage will launch the EarthStore facility later this year—a project utilizing Earth’s natural energy storage capacity to produce clean, sustainable, and dispatchable electricity on demand. EarthStore technology creates a reliable, resilient power source independent of weather conditions, including wind and sunshine.

“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.”

Test well in Starr County, TX; Image Credits: Sage Geosystems

Sage will apply for two drilling permits in Texas: the first in Atascosa County for GGS and the second in Starr County, in proximity to Sage’s existing test well.

Geothermal Energy

Geothermal power generation is an increasingly attractive method of energy production and storage and Joseph Bonafin, Sales and Business Development Manager at Turboden, offers his insight on turbomachinery in a geothermal plant, recent advancements, and geothermal’s role in decarbonization.

“The turbomachinery is the rotating part that converts pressure in the organic fluid into work and electricity by spinning a generator,” said Bonafin. “Pressure in the organic fluid is created by a heat exchanger transferred from a geothermal source, so no geothermal fluids are used. A closed-and-tight circuit generates emissions-free power. Turbomachinery is key to having an efficient and reliable baseload generation with low maintenance costs.”

This power source could be a potential pathway toward a carbon-minimal energy landscape, replacing more traditional operations, “Geothermal generates power year-round and can replace coal- or gas-fired power stations as a baseload power with low production costs,” said Bonafin. “It’s also dispatchable and supports grid stability in combination with intermittent sources. It’s also easily integrated into most locations with a small footprint and CO₂ lifecycle compared to other renewables such as solar and wind. Plus, geothermal provides not only electrical power but inexpensive thermal power for a district heating network—not to mention that geothermal projects create temporary and permanent jobs that are important in developing a local supply chain.”