hot off the press

Houston-based geothermal energy startup releases promising results of Texas pilot

Houston startup Sage Geosystems released the results of its pilot at a Shell-drilled oil well in the Rio Grande Valley’s Starr County. Photo via

As it seeks an additional $30 million in series A funding, Houston startup Sage Geosystems has released promising results from a test of its technology for underground storage of geothermal energy.

Sage says the pilot project, conducted at a Shell-drilled oil well in the Rio Grande Valley’s Starr County, showed the company’s long-term energy storage can compete on a cost basis with lithium-ion battery storage, hydropower storage, and natural gas-powered peaker plants. Peaker plants supply power during periods of peak energy demand.

Furthermore, Sage’s geothermal technology will provide more power capacity at half the cost of other advanced geothermal systems, the company says.

Sage’s storage system retrofits oil and gas wells with the company’s geothermal technology. But the company says its technology “can be deployed virtually anywhere.”

The system relies on mechanical storage instead of battery storage. In mechanical storage, heat, water, or air works in tandem with compressors, turbines, and other machinery. By contrast, battery storage depends on chemistry to get the job done.

“We have cracked the code to provide the perfect complement to renewable energy. … The opportunities for our energy storage to provide power are significant — from remote mining operations to data centers to solving energy poverty in remote locations,” former Shell executive Cindy Taff, CEO of Sage, says in a September 12 news release.

Sage says its storage capacity can be connected to existing power grids, or it can develop microgrids that harness stored energy.

An August 2023 article in The New York Times explained that Sage “is pursuing fracked wells that act as batteries. When there’s surplus electricity on the grid, water gets pumped into the well. In times of need, pressure and heat in the fractures pushes water back up, delivering energy.”

The pilot project, a joint venture between Sage and the Bureau of Economic Ecology at the University of Texas at Austin, was performed as part of a feasibility study financed by the Air Force. Now that the test results are in, Sage plans to build a prototype geothermal project at the Air Force’s Ellington Field Joint Reserve Base in Houston.

Sage says another feasibility study is underway in the Middle East in partnership with an unnamed oil and gas company.

Founded in 2020, Sage plans to raise another $30 million to accompany its previous series A funding.

The Virya climate fund and Houston-based drilling contractor Nabors Industries helped finance the pilot project in Starr County.

Last year, Sage announced it received an undisclosed amount of equity from Houston-based Ignis H2 Energy, a geothermal exploration and development company, and Dutch energy company Geolog International. Also last year, Sage said Nabors and Virya had teamed up for a $12 million investment in the startup.

Trending News

A View From HETI

Discovery Green's Earth Day event generated more than 3,800 pounds of garbage — and over 90 percent of it was diverted from landfills. Photo courtesy of Discovery Green

Discovery Green celebrated Earth Day with a major milestone this year — achieving it’s Zero Waste goal.

The nonprofit, along with Citizens’ Environmental Coalition and Houston Public Works, are announced that the 2024 Green Mountain Energy Earth Day, which generated more than 3,800 pounds of garbage, diverted the majority of that waste from landfills. "Zero Waste," as defined by the Environmental Protection Agency, is successfully diverting at least 90 percent of waste from the landfill.

On Earth Day, Discovery Green composted 2,200 pounds of waste and recycled 1,300 pounds of trash.

“Part of Discovery Green Conservancy’s mission is to serve as a village green for our city and be a source of health and happiness for all. Our goal is to sustain an exceptional environment for nature and people,” Discover Green President Kathryn Lott says in a news release. “We are beyond thrilled to have achieved Zero Waste certification.”

The achievement was made possible by volunteers from the University of Houston – Downtown.

Steve Stelzer, president of Citizens’ Environmental Coalition’s board of directors, acknowledged how rare the achievement is in a public space in a major city like Houston.

“Discovery Green Conservancy stepped up and made a commitment to weigh, measure and record everything. They should be congratulated to have done this at this scale,” Stelzer adds. “The Conservancy said they were going to do it and they did. It’s an amazing accomplishment.”

The 2024 event included:

  • 31,000 visitors in attendance
  • 60 + exhibitors
  • 100 + volunteers
  • 12 artists
    • 9 chalk artists
    • Donkeeboy and Donkeemom
    • Mark Bradford
  • 25 Mark Bradford artworks made of scrap presented in partnership with Houston First
  • 4 short films shown
  • 3,836.7 pounds of waste collected during Green Mountain Energy Earth Day

Trending News