Q&A

Geothermal exec on Houston expansion, commercialization and more

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.

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A View From HETI

No critical minerals, no modern economy. Getty images

If you’re reading this on a phone, driving an EV, flying in a plane, or relying on the power grid to keep your lights on, you’re benefiting from critical minerals. These are the building blocks of modern life. Things like copper, lithium, nickel, rare earth elements, and titanium, they’re found in everything from smartphones to solar panels to F-35 fighter jets.

In short: no critical minerals, no modern economy.

These minerals aren’t just useful, they’re essential. And in the U.S., we don’t produce enough of them. Worse, we’re heavily dependent on countries that don’t always have our best interests at heart. That’s a serious vulnerability, and we’ve done far too little to fix it.

Where We Use Them and Why We’re Behind

Let’s start with where these minerals show up in daily American life:

  • Electric vehicles need lithium, cobalt, and nickel for batteries.
  • Wind turbines and solar panels rely on rare earths and specialty metals.
  • Defense systems require titanium, beryllium, and rare earths.
  • Basic infrastructure like power lines and buildings depend on copper and aluminum.

You’d think that something so central to the economy, and to national security, would be treated as a top priority. But we’ve let production and processing capabilities fall behind at home, and now we’re playing catch-up.

The Reality Check: We’re Not in Control

Right now, the U.S. is deeply reliant on foreign sources for critical minerals, especially China. And it’s not just about mining. China dominates processing and refining too, which means they control critical links in the supply chain.

Gabriel Collins and Michelle Michot Foss from the Baker Institute lay all this out in a recent report that every policymaker should read. Their argument is blunt: if we don’t get a handle on this, we’re in trouble, both economically and militarily.

China has already imposed export controls on key rare earth elements like dysprosium and terbium which are critical for magnets, batteries, and defense technologies, in direct response to new U.S. tariffs. This kind of tit-for-tat escalation exposes just how much leverage we’ve handed over. If this continues, American manufacturers could face serious material shortages, higher costs, and stalled projects.

We’ve seen this movie before, in the pandemic, when supply chains broke and countries scrambled for basics like PPE and semiconductors. We should’ve learned our lesson.

We Do Have a Stockpile, But We Need a Strategy

Unlike during the Cold War, the U.S. no longer maintains comprehensive strategic reserves across the board, but we do have stockpiles managed by the Defense Logistics Agency. The real issue isn’t absence, it’s strategy: what to stockpile, how much, and under what assumptions.

Collins and Michot Foss argue for a more robust and better-targeted approach. That could mean aiming for 12 to 18 months worth of demand for both civilian and defense applications. Achieving that will require:

  • Smarter government purchasing and long-term contracts
  • Strategic deals with allies (e.g., swapping titanium for artillery shells with Ukraine)
  • Financing mechanisms to help companies hold critical inventory for emergency use

It’s not cheap, but it’s cheaper than scrambling mid-crisis when supplies are suddenly cut off.

The Case for Advanced Materials: Substitutes That Work Today

One powerful but often overlooked solution is advanced materials, which can reduce our dependence on vulnerable mineral supply chains altogether.

Take carbon nanotube (CNT) fibers, a cutting-edge material invented at Rice University. CNTs are lighter, stronger, and more conductive than copper. And unlike some future tech, this isn’t hypothetical: we could substitute CNTs for copper wire harnesses in electrical systems today.

As Michot Foss explained on the Energy Forum podcast:

“You can substitute copper and steel and aluminum with carbon nanotube fibers and help offset some of those trade-offs and get performance enhancements as well… If you take carbon nanotube fibers and you put those into a wire harness… you're going to be reducing the weight of that wire harness versus a metal wire harness like we already use. And you're going to be getting the same benefit in terms of electrical conductivity, but more strength to allow the vehicle, the application, the aircraft, to perform better.”

By accelerating R&D and deployment of CNTs and similar substitutes, we can reduce pressure on strained mineral supply chains, lower emissions, and open the door to more secure and sustainable manufacturing.

We Have Tools. We Need to Use Them.

The report offers a long list of solutions. Some are familiar, like tax incentives, public-private partnerships, and fast-tracked permits. Others draw on historical precedent, like “preclusive purchasing,” a WWII tactic where the U.S. bought up materials just so enemies couldn’t.

We also need to get creative:

  • Repurpose existing industrial sites into mineral hubs
  • Speed up R&D for substitutes and recycling
  • Buy out risky foreign-owned assets in friendlier countries

Permitting remains one of the biggest hurdles. In the U.S., it can take 7 to 10 years to approve a new critical minerals project, a timeline that doesn’t match the urgency of our strategic needs. As Collins said on the Energy Forum podcast:

“Time kills deals... That’s why it’s more attractive generally to do these projects elsewhere.”

That’s the reality we’re up against. Long approval windows discourage investment and drive developers to friendlier jurisdictions abroad. One encouraging step is the use of the Defense Production Act to fast-track permitting under national security grounds. That kind of shift, treating permitting as a strategic imperative, must become the norm, not the exception.

It’s Time to Redefine Sustainability

Sustainability has traditionally focused on cutting carbon emissions. That’s still crucial, but we need a broader definition. Today, energy and materials security are just as important.

Countries are now weighing cost and reliability alongside emissions goals. We're also seeing renewed attention to recycling, biodiversity, and supply chain resilience.

Net-zero by 2050 is still a target. But reality is forcing a more nuanced discussion:

  • What level of warming is politically and economically sustainable?
  • What tradeoffs are we willing to make to ensure energy access and affordability?

The bottom line: we can’t build a clean energy future without secure access to materials. Recycling helps, but it’s not enough. We'll need new mines, new tech, and a more flexible definition of sustainability.

My Take: We’re Running Out of Time

This isn’t just a policy debate. It’s a test of whether we’ve learned anything from the past few years of disruption. We’re not facing an open war, but the risks are real and growing.

We need to treat critical minerals like what they are: a strategic necessity. That means rebuilding stockpiles, reshoring processing, tightening alliances, and accelerating permitting across the board.

It won’t be easy. But if we wait until a real crisis hits, it’ll be too late.

———

Scott Nyquist is a senior advisor at McKinsey & Company and vice chairman, Houston Energy Transition Initiative of the Greater Houston Partnership. The views expressed herein are Nyquist's own and not those of McKinsey & Company or of the Greater Houston Partnership. This article originally appeared on LinkedIn on April 11, 2025.


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