Axel-Pierre Bois, XGS Energy's Chief Technology Officer. Photo courtesy XGS Energy

Challenges in the energy transition often center around two questions: Where will organizations find the resources? And how will projects be financed?

XGS Energy's next-gen closed-loop geothermal well architecture addresses both issues head-on. The California-based company saw massive growth in the Houston market last year and recently completed a 100-meter field demonstration in central Texas, marking a major milestone for its technology's commercialization and potential for scale.

In an interview with EnergyCapital, Axel-Pierre Bois, XGS's Chief Technology Officer, shares what drew him to the geothermal space, why XGS is expanding in Houston and what the company's plans are for the year ahead.

How does XGS Energy's technology address the biggest challenges in geothermal energy?

XGS Energy is developing a geothermal system that decouples geothermal energy from its traditional dependence on water and geology to deliver affordable, clean energy anywhere there is hot rock.

Historically, geothermal resources have been hard to locate, as conventional systems require the overlap of hot rock, porous and permeable geology, and abundant water to produce energy, limiting their potential to a few select hot spots worldwide. Instead of relying on an underground fracture network that drives the geology and water requirements, the base component of XGS’s system is a single well, in which fluid is pumped to a hot rock resource and then returned to the surface through a tube-in-shell design, creating a sealed, closed loop. This allows XGS to produce geothermal energy anywhere where there is hot rock, unlocking terawatt-scale potential in the U.S. alone.

Geothermal systems have also struggled to secure project financing, as many systems have historically faced high levels of unplanned cost risk due to factors including water loss and production uncertainty. XGS’s sealed, closed-loop system ensures that it can provide reliable, predictable electricity throughout its lifespan. XGS also boosts the cost-competitiveness of its system through our major innovation, a proprietary thermally conductive materials system that is installed downhole around each well, increasing the heat transferred to the closed-loop system by 30-50%.

What has drawn you to a career in the geothermal energy space?

I have been in the subsurface industry for over 30 years, developing technical solutions for companies in the fields of geosciences, underground storage, upstream oil and gas, and geothermal heat harvesting to help improve their overall economic, ethical and environmental footprints. In 2009, I founded Curistec, a technology company providing research, engineering and technical services for geomechanics, wellbore integrity, well abandonment, cement design and cement and rock testing. A few years back, Curistec assisted with the Iceland Deep Drilling Project, helping to develop cement formulations for superhot geothermal well applications to enable drilling in high-temperature environments. As I looked toward the future, it became clear that next-generation geothermal technologies would transform the geothermal energy industry and open new markets worldwide. Curistec had been working closely with the XGS Energy team as technology partners for several years, so joining the team directly to help shape the technology development was an exciting opportunity to help develop and deploy a new system to unlock the full terawatt-scale potential of geothermal energy.

Tell us about the 100-meter field demonstration in central Texas completed in 2024 — what all did you and your team learn from the test?

Our 100-meter field demonstration in central Texas marked a significant step in our progress toward deploying geothermal energy in a commercial setting. With this field operation, we successfully demonstrated our ability to mix, pump and place our thermally conductive materials system at a commercial scale, using off-shelf tools and technologies. This was a significant milestone, taking us from theoretical models and laboratory tests to field-scale operations, proving that our novel geothermal system is operationally viable in real-world well conditions.

The completion of the Texas field demonstration advanced XGS into the new wave of geothermal innovators that are putting real steel in the ground. In 2024, we kicked off construction at our commercial-scale demonstration in California and are excited to share updates in the year ahead.

Last year, XGS Energy leased over 10,000 square feet of office space in Memorial City. How has Houston's business community and opportunities benefitted the company?

Houston, the epicenter of the oil and gas industry, has become a hub of energy innovation, offering attractive incentives for growing companies like XGS. The region’s workforce, which is home to some of the best subsurface engineers and operational talent in the energy sector, was a key factor for XGS when we were planning our operational roadmap. This expertise, paired with proximity to our partners in the field services industries, like cementing and drilling, is both apracticaland tactical advantage for XGS.

We’ve built a strong technical and operational team here at XGS, with experience from the oil and gas industry, utilities and power project developers. XGS is planning for continued growth in the Houston area, leveraging the region’s leading engineering and operational workforce and its intensifying interest in supporting the energy transition.

What are XGS Energy's goals for 2025?

In 2024, the XGS Energy team made significant progress toward our goal of providing clean, round-the-clock energy with our solid-state geothermal system. In 2025, XGS Energy will be focused on deploying its geothermal system at a commercial scale, starting with the completion of our full-scale prototype in California. XGS will also continue accelerating our commercial traction, expanding our already robust and highly differentiated geothermal resource evaluation toolkit, advancing our global project pipeline, and growing our team to strengthen our operational capability and capacity.

The deal brings Fervo's total funding secured this year to around $600 million. Photo courtesy of Fervo

Houston-based Fervo Energy collects $255M in additional funding

cha-ching

A Houston company that's responding to rising energy demand by harnessing geothermal energy through its technology has again secured millions in funding. The deal brings Fervo's total funding secured this year to around $600 million.

Fervo Energy announced that it has raised $255 million in new funding and capital availability. The $135 million corporate equity round was led by Capricorn’s Technology Impact Fund II with participating investors including Breakthrough Energy Ventures, CalSTRS, Congruent Ventures, CPP Investments, DCVC, Devon Energy, Galvanize Climate Solutions, Liberty Mutual Investments, Mercuria, and Sabanci Climate Ventures.

The funding will go toward supporting Fervo's ongoing and future geothermal projects.

“The demand for 24/7 carbon-free energy is at an all-time high, and Fervo is one of the only companies building large projects that will come online before the end of the decade,” Fervo CEO and Co-Founder Tim Latimer says in a news release. “Investors recognize that Fervo’s ability to get to scale quickly is vital in an evolving market that is seeing unprecedented energy demand from AI and other sources.”

Additionally, Fervo secured a $120 million letter of credit and term loan facility from Mercuria, an independent energy and commodity group that previously invested in the company.

“In surveying power markets across the U.S. today, the need for next-generation geothermal is undeniable,” Brian Falik, group chief investment officer of Mercuria, adds. “We believe in Fervo not just because their EGS approach is cost-effective, commercially viable, and already being deployed at scale, but because they set ambitious targets and consistently deliver.”

In February, Fervo secured $244 million in a financing round led by Devon Energy, and in September, the company received a $100 million bridge loan for the first phase of its ongoing project in Utah. This project, known as Project Cape, represents a 100x growth opportunity for Fervo, as Latimer explained to InnovationMap earlier this year. As of now, Project Cape is fully permitted up to 2 GW and will begin generating electricity in 2026, per the company.

Other wins for Fervo this year include moving into its new headquarters in downtown Houston, securing a power purchase agreement with California, growing its partnership with Google, and being named amongst the year's top inventions by Time magazine.


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This article originally ran on InnovationMap.

In a recent Energy Tech Startups Podcast episode, Cindy Taff discussed the evolution of Sage GeoSystems, the challenges of scaling hard tech solutions, and the opportunities presented by geothermal and pumped hydro energy storage. Photo courtesy of Sage

Houston founder on driving the future of geothermal energy, storage

now streaming

Cindy Taff, co-founder and CEO of Sage GeoSystems, has emerged as a visionary leader in the energy transition, recently named to Time magazine’s 100 Most Influential Climate Leaders in Business for 2024. Under her leadership, Sage is not only advancing geothermal energy innovation but also redefining how energy storage can support a renewable-powered grid.

In a recent Energy Tech Startups Podcast episode, Taff discussed the evolution of Sage GeoSystems, the challenges of scaling hard tech solutions, and the opportunities presented by geothermal and pumped hydro energy storage. Her insights reflect the unique perspective of a founder bridging oil and gas expertise with renewable energy innovation.

- YouTubeCindy shares how Sage Geosystems is leveraging its oil and gas expertise to develop groundbreaking subsurface pumped hydro ...

Breaking Boundaries with Geopressured Geothermal Systems

Sage GeoSystems is at the forefront of next-generation geothermal energy, advancing Geopressured Geothermal Systems (GGS) that can be deployed in a wide range of geographies. Unlike traditional geothermal systems, which rely on natural water reservoirs near volcanic activity, Sage’s engineered reservoirs allow geothermal energy to be tapped almost anywhere.

“Geothermal energy is no longer restricted to specific conditions,” Taff explained. “Our systems are flexible, scalable, and capable of meeting the needs of energy-intensive applications like data centers—including a recent deal with Meta to deliver 150 megawatts of geothermal power for their facilities.”

This adaptability sets Sage apart, offering a path to reliable, clean energy that can complement intermittent sources like wind and solar. Sage also secured a win in the Energy Transition Business category alongside notable finalists like Amperon and Tierra Climate, underscoring its leadership in innovative energy solutions.

Pivoting Toward Subsurface Energy Storage

While initially focused solely on geothermal, Sage uncovered a transformative opportunity in subsurface pumped hydro energy storage during field trials. Dubbed “upside-down pumped hydro,” the solution provides long-duration energy storage capable of balancing the grid for 17+ hours—far surpassing the capabilities of lithium-ion batteries for extended periods.

“Pumped storage hydropower is a critical piece of the energy puzzle,” Taff emphasized. By storing energy during off-peak times and releasing it when solar and wind aren’t producing, Sage is helping bridge the intermittency gap in renewables. This approach positions pumped storage as a game-changer for a reliable, clean energy grid.

Lessons from the Founder’s Journey

Taff’s transition from a 35-year career at Shell to geothermal entrepreneurship offers valuable lessons for founders in capital-intensive industries:

  1. Leverage Expertise, but Stay Open to New Solutions:
    Taff’s oil and gas background enabled her to approach geothermal with deep technical knowledge, but Sage’s pivot to energy storage illustrates the importance of staying adaptable during development.
  2. Educate Financial Stakeholders:
    Securing funding for hard tech remains a challenge. “Investors often lack the subsurface knowledge needed to understand our technology,” Taff explained. She emphasized the need to bring on team members who can translate technical innovation into financial terms.
  3. Be Ready for Capital-Intensive Scaling:
    With geothermal plants costing millions to build, startups must carefully manage capital and timelines. Taff encourages founders to seek strategic investors, like Chesapeake Energy, who understand the challenges and potential of scaling infrastructure.

Beyond Geothermal: A Call for Pumped Storage Hydropower

In addition to geothermal, Taff champions pumped storage hydropower as an underutilized climate solution. “While lithium-ion batteries get a lot of attention, pumped storage hydropower offers long-duration storage that can stabilize the grid for days, not just hours,” she said.

By storing excess energy during off-peak times and releasing it when solar and wind aren’t producing, pumped storage hydropower can play a critical role in balancing renewables. Sage GeoSystems is uniquely positioned to integrate this technology into a broader energy strategy, offering sustainable and scalable solutions for energy-intensive industries.

A Vision for Geothermal and the Energy Transition

Looking ahead, Taff sees geothermal energy and storage as critical components of a sustainable energy mix. “We’re still in the early stages, but geothermal is following a trajectory similar to wind and solar 15 years ago,” she said. Sage’s innovative approaches are paving the way for geothermal to become a scalable, competitive solution, capable of powering industries and data centers while providing energy storage that stabilizes the grid.

With her recognition by Time magazine and a recent deal with Meta, Sage GeoSystems is proving that geothermal energy can be a powerful ally in achieving global decarbonization goals. The company’s innovative Geopressured Geothermal Systems and subsurface storage solutions are laying the groundwork for a reliable and sustainable energy future.

Listen to the full episode with Cindy Taff on the Energy Tech Startups Podcast here.

Energy Tech Startups Podcast is hosted by Jason Ethier and Nada Ahmed. It delves into Houston's pivotal role in the energy transition, spotlighting entrepreneurs and industry leaders shaping a low-carbon future.


Fervo Energy received $100 million loan for its Utah Cape Station project. Photo via fervoenergy.com

Houston company secures $100M for 'world’s largest geothermal energy plant'

loan guarenteed

Houston-based geothermal energy company Fervo Energy has secured a $100 million bridge loan for the first phase of its ongoing project in Utah.

The loan came from an affiliate of Irvington, New York-based X-Caliber Rural Capital. Proceeds will support construction of Fervo’s Cape Station project, which is being touted as the world’s largest geothermal energy plant.

The first phase of Cape Station, which is on track to generate 90 megawatts of renewable energy, is expected to be completed in June 2026. Ultimately, the plant is supposed to supply 400 megawatts of clean energy by 2028 for customers in California.

“Helping this significant project advance and grow in rural America is a true testament to how investing in communities and businesses not only has local influence, but can have a global, long-lasting impact by promoting sustainability and stimulating rural economies,” Jordan Blanchard, co-founder of X-Caliber Rural Capital, says in a news release.

X-Caliber Rural Capital is an affiliate of commercial real estate financing company X-Caliber Capital Holdings.

Fervo says its drilling operations Utah’s Cape Station show a 70 percent reduction in drilling times, paving the way for advancement of its geothermal energy system.

Tim Latimer, co-founder and CEO of Fervo, says his company’s drilling advancements, purchase deals, transmission rights, permit approvals, and equipment acquisitions make Fervo “an ideal candidate” for debt financing. In May, Latimer joined the Houston Innovators Podcast to discuss the company's growth and latest project.

With a new office in downtown Houston, Fervo recently signed up one of the country’s largest utilities as a new customer and expanded its collaboration with Google.

To date, Fervo has raised $531 million in venture capital funding, per Crunchbase data.

Houston startup Sage Geosystems has tapped a utility provider for an energy storage facility in the San Antonio metro area. Photo via sagegeosystems.com

Houston geothermal startup selects Texas location for first energy storage facility

major milestone

Houston-based geothermal energy startup Sage Geosystems has teamed up with a utility provider for an energy storage facility in the San Antonio metro area.

The three-megawatt EarthStore facility will be on land controlled by the San Miguel Electric Cooperative, which produces electricity for customers in 47 South Texas counties. The facility will be located in the town of Christine, near the cooperative’s coal-fired power plant.

Sage says its energy storage system will be paired with solar energy to supply power for the grid operated by the Electric Reliability Council of Texas (ERCOT). The facility is set to open later this year.

“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,” Cindy Taff, CEO of Sage Geosystems, says in a news release.

The facility is being designed to store geothermal energy during six- to 10-hour periods.

“Long-duration energy storage is crucial for the ERCOT utility grid, especially with the increasing integration of intermittent wind and solar power generation,” says Craig Courter, CEO of the San Miguel Electric Cooperative.

Through a first-of-its-kind proposal, Las Vegas-based public utility NV Energy would supply geothermal power generated by Fervo Energy for Google’s two data centers in Nevada. Screenshot via Google

Houston geothermal company grows relationship with Google to provide power to Nevada

powering up

Houston-based Fervo Energy’s geothermal energy soon will help power the world’s most popular website.

Through a first-of-its-kind proposal, Las Vegas-based public utility NV Energy would supply 115 megawatts of geothermal power generated by Fervo for Google’s two data centers in Nevada. Financial terms weren’t disclosed.

In 2021, Google teamed up with Fervo to develop a pilot project for geothermal power in Nevada. Two years later, electricity from this project started flowing into the Nevada grid serving the two Google data centers. Google spent $600 million to build each of the centers, which are in Henderson, a Las Vegas suburb, and Storey County, which is east of Reno.

The proposed agreement with NV Energy would bring about 25 times more geothermal power capacity to the Nevada grid, Google says, and enable more around-the-clock clean power for the search engine company’s Nevada data centers.

A data center gobbles up 10 to 50 times the energy per square foot of floor space that a typical office building does, according to the U.S. Department of Energy.

“NV Energy and Google’s partnership to develop new solutions to bring clean … energy technology — like enhanced geothermal — onto Nevada’s grid at this scale is remarkable. This innovative proposal will not be paid for by NV Energy’s other customers but will help ensure all our customers benefit from cleaner, greener energy resources,” Doug Cannon, president and CEO of NV Energy, says in a Google blog post.

Utility regulators still must sign off on the proposal.

“If approved, it provides a blueprint for other utilities and large customers in Nevada to accelerate clean energy goals,” Cannon says.

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8 Houston energy companies land on Time's top greentech list for 2025

top honor

The accolades keep rolling in for Houston-based Fervo Energy, a producer of geothermal power.

Fervo lands at No. 6 on Time magazine and Statista’s new list of America’s Top GreenTech Companies of 2025. The ranking recognizes sustainability-focused companies based on factors such as impact, financial strength, and innovation.

Time notes that Fervo broke ground in 2023 in Utah on what the company claims will be the world’s largest geothermal plant. The plant is scheduled to start supplying carbon-free electricity to the grid next year and to reach its 400-megawatt capacity in three years.

“Technologies like this only make a difference if we deploy them at large-scale in a way that can reduce carbon emissions and increase the reliability of the grid,” Fervo CEO Tim Latimer told Time in 2023.

The startup was named North American Company of the Year by research and consulting firm Cleantech Group for 2025. Fervo topped the Global Cleantech 100, Cleantech Group’s annual list of the world’s most innovative and promising cleantech companies.

Last year, Fervo also made Time’s list of the 200 Best Inventions of 2024. Fervo was recognized in the green energy category for its FervoFlex geothermal power system.

Founded in 2017, Fervo is now a unicorn, meaning its valuation as a private company exceeds $1 billion. The startup’s valuation is estimated at $1.4 billion. According to PitchBook data, the company raised $634 million in the fourth quarter of 2024.

In all, eight Houston-area companies appear among the top 250 greentech companies ranked by Time and Statista. Other than Fervo, they are:

  • No. 43 Lancium Technologies, an energy storage and distribution company
  • No. 50 Solugen, a producer of sustainable chemicals.
  • No. 56 Quaise Energy, which specializes in terawatt-scale geothermal power.
  • No. 129 Plus Power, a developer, owner and operator of battery storage projects.
  • No. 218 Dream Harvest, which promotes sustainable vertical farming.
  • No. 225 Cemvita, which uses synthetic biology to convert carbon emissions into bio-based chemicals.
  • No. 226 Syzygy Plasmonics, which decarbonizes chemical production.
Vermont-based BETA Technologies claimed the No. 1 spot. The company manufactures electric aircraft.

Global co. opens state-of-the-art energy innovation hub in Houston

flagship facility

French multinational company Schneider Electric has opened a new 10,500-square-foot, state-of-the-art Energy Innovation Center in Houston.

The new facility is located in Houston’s Energy Corridor and is designed to “foster increased collaboration and technological advancements across the entire value chain,” according to a news release from the company. The new Houston location joins Schneider's existing innovation hubs in Paris, Singapore and Bangalore.

The venue will serve as a training center for process control engineers, production superintendents, manufacturing managers, technical leads and plant operations personnel. It can simulate various real-world scenarios in refineries, combined-cycle power plants, ethylene plants, recovery boilers and chemical reactors.

It includes an interactive control room and artificial Intelligence applications that “highlight the future of industrial automation,” according to the release.

"Digitalization is significantly enhancing the global competitiveness of the U.S. through continuous innovation and increased investment into next-generation technology," Aamir Paul, Schneider Electric's President of North America Operations, said in the release.

Texas has over 4,100 Schneider Electric employees, the most among U.S. states, and has facilities in El Paso, the Dallas-Fort Worth metroplex and other areas.

"This flagship facility in the Energy Capital of the World underscores our commitment to driving the future of software-defined automation for our customers in Houston and beyond,” Paul added in the release. “With this announcement, we are excited to continue supporting the nation's ambitions around competitive, efficient and cost-effective manufacturing."

Schneider Electric says the new Houston facility is part of its expansion plans in the U.S. The company plans to invest over $700 million in its U.S. operations through 2027, which also includes an expansion at its El Paso campus.

The company also announced plans to invest in solar and battery storage systems developed, built, and operated by Houston-based ENGIE North America last year. Read more here.