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

hot off the press

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 sagegeosystems.com

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.

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Houston hypersonic engine co. completes first successful test flight

Taking Off

Houston-based Venus Aerospace successfully completed the first U.S. flight test of its proprietary engine at a demonstration at Spaceport America in New Mexico.

Venus’ next-generation rotating detonation rocket engine (RDRE) is supported by a $155,908 federal Small Business Innovation Research (SBIR) grant from NASA and aims to enable vehicles to travel four to six times the speed of sound from a conventional runway. The recent flight test was the first of an American-developed engine of its kind.

"With this flight test, Venus Aerospace is transforming a decades-old engineering challenge into an operational reality,” Thomas d'Halluin, managing partner at Airbus Ventures, an investor in Venus, said in a news release. “Getting a rotating detonation engine integrated, launch-ready, and validated under real conditions is no small feat. Venus has shown an extraordinary ability to translate deep technical insight into hardware progress, and we're proud to support their bold approach in their attempt to unlock the hypersonic economy and forge the future of propulsion."

Venus’ RDRE operates through supersonic shockwaves, called detonations, that generate more power with less fuel. It is designed to be affordable and scalable for defense and commercial systems.

The RDRE is also engineered to work with the company's air-breathing detonation ramjet, the VDR2, which helps enable aircraft to take off from a runway and transition to speeds exceeding Mach 6. Venus plans for full-scale propulsion testing and vehicle integration of this system. Venus’ ultimate goal is to develop a Mach 4 reusable passenger aircraft, known as the Stargazer M4.

"This milestone proves our engine works outside the lab, under real flight conditions," Andrew Duggleby, Venus co-founder and chief technology officer, said in the release. "Rotating detonation has been a long-sought gain in performance. Venus' RDRE solved the last but critical steps to harness the theoretical benefits of pressure gain combustion. We've built an engine that not only runs, but runs reliably and efficiently—and that's what makes it scalable. This is the foundation we need that, combined with a ramjet, completes the system from take-off to sustained hypersonic flight."

The hypersonic market is projected to surpass $12 billion by 2030, according to Venus.

"This is the moment we've been working toward for five years," Sassie Duggleby, CEO and co-founder of Venus Aerospace, added. "We've proven that this technology works—not just in simulations or the lab, but in the air. With this milestone, we're one step closer to making high-speed flight accessible, affordable, and sustainable."

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This article originally appeared on InnovationMap.com.

Investment giant to acquire TXNM Energy for $11.5 billion

m&a moves

Blackstone Infrastructure, an investment giant with $600 million in assets under management, has agreed to buy publicly traded TXNM Energy in a debt-and-stock deal valued at $11.5 billion.

TXNM Energy is the parent company of Lewisville-based Texas New Mexico Power (TNMP), which supplies electricity to more than 270,000 homes and businesses throughout Texas. Its Houston-area service territory includes Alvin, Angleton, Brazoria, Dickinson, Friendswood, La Marque, League City, Sweeny, Texas City and West Columbia.

Once Blackstone Infrastructure wraps up the deal in the second half of 2026, Albuquerque, New Mexico-based TXNM will no longer be a public company. But TNMP’s headquarters will remain in Texas and its rates will continue to be set by the Public Utility Commission of Texas. TNMP was founded in 1934.

Blackstone Infrastructure is affiliated with investment powerhouse Blackstone Inc., which has $1.2 trillion in assets under management and is the world’s largest investment manager.

“TNMP has done an excellent job of meeting its customers’ growing demand for electricity and supporting the communities it serves,” Sean Klimczak, Blackstone’s global head of infrastructure, said in a news release. “We look forward to utilizing our long-term investment commitments to support TNMP as they continue on this path of high-demand growth across Texas.”

During TXNM’s fourth-quarter earnings call in February, Chairwoman and CEO Patricia Vincent-Collawn said the company’s five-year Texas capital investment plan had grown by more than $1 billion.

“Our future is so bright with these increased investment levels that we are now targeting earnings growth of 7 percent to 9 percent through 2029,” Vincent-Collawn said.

“Our financial expectations are driven by the continued expansion of grid infrastructure supporting growth and reliability in our Texas service territory,” she added.

In 2024, TXNM reported revenue of $1.96 billion, up 1.7 percent from the previous year.

$135 million Houston battery storage facility breaks ground

coming soon

SMT Energy and CenterPoint Energy have partnered with utility infrastructure solutions provider Irby Construction Company to break ground on a 160 megawatt battery energy storage system (BESS) located in the Houston zone of the ERCOT market.

“We are proud to be underway and deliver this grid-strengthening project to Houston,” Kevin Midei, SVP of engineering, procurement and construction, at SMT Energy, said in a news release.

The BESS, SMT Houston IV, is expected to support grid stability, deliver fast-response power during peak demands and provide resiliency and renewable integration. The project is expected to be online by 2026 and store and dispatch enough electricity to power 8,800 homes in Texas annually.

SMT Energy is the project owner and developer, and CenterPoint Energy will serve as the interconnecting utility, integrating the system into Houston’s broader electrical network,” according to the companies. Irby Construction will serve as the engineering, procurement, and construction (EPC) contractor, and construction of the project is expected to be completed by July. On May 14, the companies broke ground with a ribbon-cutting ceremony to symbolize the start of the build.

“Projects like this demonstrate how collaboration and forward-thinking infrastructure come together to power a more resilient energy future,” Tony Gardner, SVP and chief customer officer at CenterPoint, said in a news release. “At CenterPoint, we recently completed nearly 90 percent of our overall grid resiliency improvements. This is one more action we are taking to build a more resilient and reliable grid to better serve our customers.”

In March, Colorado-based SMT Energy secured $135 million in funding for the SMT Houston IV, led by Macquarie and KeyBanc Capital Markets as joint lead arrangers. In 2023, SMT Energy and joint venture partner SUSI Partners announced plans to add 10 battery storage projects to Texas, which would double capacity from 100 megawatts to 200 megawatts in the Houston and Dallas areas.

In 2019, Irby began construction on the Manatee BESS site with Florida Power and Light (FPL), which was the world’s largest BESS project at the time. Irby has built over 30 BESS sites and has more than 20 currently under construction or contract.

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