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“We grew quickly and made some mistakes,” Generate executive Jonah Goldman told Heatmap.
A new list of grant cancellations obtained by Heatmap includes Climeworks and Heirloom projects funded by 2021 infrastructure law.
On Trump’s metal nationalization spree, Tesla’s big pitch, and fusion’s challenges
Shine Technologies is getting close to breakeven — on operations, at least — by selling neutrons and isotopes.
Some of the industry’s biggest names are joining forces to keep the momentum moving forward.
The company is vying to challenge Fervo for leadership in the next-generation geothermal market.
The geothermal startup XGS Energy has now completed four months of tests to see whether its technology can maintain steady production of heat at temperatures above what’s needed to generate energy. Over 3,000 hours, the company monitored the drilling process and checked how heat flowed from its wells, the status of their temperature, and how precisely XGS’ mathematical predictions matched the outcome of the testing.
The results, which the company shared exclusively with Heatmap, were “almost too good,” XGS CEO Josh Prueher told me.
“Had we been within 10% of predictive performance, we would have been pretty happy with the outcome,” Prueher said. “Turns out we were within 2% under a variety of different parameters.”
“It worked like a charm,” he said.
To understand what makes XGS Energy stand out among the geothermal startups racing to commercialize next-generation technology, it helps to compare the company to its fellow Houston-based rival that’s currently leading the sector, Fervo Energy. Unlike Fervo, XGS doesn’t use fracking technology to drill horizontal wells in pursuit of hot, dry rocks from which to harvest energy.
Instead, XGS drills vertical wells and inserts a closed steel pipe with water and fills the gap between the metal and the rock with a patented slurry that conducts heat. Technology like Fervo’s requires pumping cold water over the fractured hot rocks to harvest heat. But with its method, XGS claims, it avoids losing any water.
The testing took place off the US-395 highway in a volcanic field in California’s Mojave desert, sandwiched between the eastern edge of the Sequoia National Park and western border of Death Valley National Park. The geothermal field XGS tapped is already actively producing energy for the Coso Operating Company, which runs a 270-megawatt geothermal power plant on the land. The results, the company said, showed the “unprecedented predictability and active control of field performance” of XGS’ technology “versus other geothermal systems, which are subject to complex and continuously changing subsurface reservoir conditions.”
At least one outside observer agreed. “This is impressive, and something to be proud of,” Advait Arun, an energy analyst and senior associate at the think tank Center for Energy Enterprise who co-authored a recent report on next-generation geothermal, told me.
While the 3,000 hours of testing still falls short of the year’s worth of data Fervo has produced at one of its sites, it’s the longest any other competitor in the space has successfully demonstrated its approach so far, Arun said.
“These guys would be second to Fervo in terms of their ability to prove a commercial-scale performance test,” he added.
XGS is now poised to build a 150-megawatt power plant for Meta’s New Mexico data centers. Even after that’s complete, however, Prueher said the surrounding area has nearly 3 gigawatts of untapped heat. In California, where the company is headquartered and carried out its demonstration project, there’s a growing need for clean power sources that don’t further tax the depleted water table.
“A lot of the historical sensitivities around developing in California — a state where, like many others, water usage for industrial development is kind of a no-no — because we don’t need water, we have some real advantages,” Prueher said.
At a moment when surging demand from data centers is supercharging dealmaking in the electricity sector, Prueher said XGS is looking beyond the boom from the artificial intelligence buildout.
“It’s not about data centers,” he said. “It really is just the fundamental power needs of California. With the restrictions around water usage, we line up really, really well for California.”
For now, the company remains focused on the U.S. But Prueher said XGS is well suited to export its technology to East Asia, as well, where countries along the Pacific Rim have vast geothermal potential and growing electricity demand but limited development. XGS already has ties to the Philippines and “may actually be subsurface” — i.e. digging wells — there by the end of 2026, Prueher told me.
The “big enchilada,” he said, would be establishing a foothold in Japan, where the onsen hotspring industry has long protested geothermal development they say could diminish the resource that makes the ancient bathhouse tradition possible. Prueher told me his technology mitigates concerns over fracking-induced earthquakes, as well.
For now, he said, his main market is in the fast-growing Southwest. The executive compared this moment to 2021, when he worked at a battery company. That February, Winter Storm Uri collapsed the Texas grid as natural gas pipes froze and demand for electricity to heat homes designed to stay cool in a typically arid climate skyrocketed. Back then, he said, batteries were “still a pretty new asset class.”
“People were still uncertain about how it would perform,” Prueher said. But his company was “able to keep our batteries up and operating 100% of the time, no one minute of downtime during that entire episode.”
“From a market perspective, the storm showed that, if you can bring this new type of technology into the market, it can really deliver remarkable value,” he added. “We made 10 years of revenue in six days.”
In a lot of ways, he went on, “this is the same thing.”
“We’ve proven a technology is reliable,” Prueher said. “It works at commercial scale over a period of time. We would regard this as a real pivot point in the industry.”
The failure of the once-promising sodium-ion manufacturer caused a chill among industry observers. But its problems may have been more its own.
When the promising and well funded sodium-ion battery company Natron Energy announced that it was shutting down operations a few weeks ago, early post-mortems pinned its failure on the challenge of finding a viable market for this alternate battery chemistry. Some went so far as to foreclose on the possibility of manufacturing batteries in the U.S. for the time being.
But that’s not the takeaway for many industry insiders — including some who are skeptical of sodium-ion’s market potential. Adrian Yao, for instance, is the founder of the lithium-ion battery company EnPower and current PhD student in materials science and engineering at Stanford. He authored a paper earlier this year outlining the many unresolved hurdles these batteries must clear to compete with lithium-iron-phosphate batteries, also known as LFP. A cheaper, more efficient variant on the standard lithium-ion chemistry, LFP has started to overtake the dominant lithium-ion chemistry in the electric vehicle sector, and is now the dominant technology for energy storage systems.
But, he told me, “Don’t let this headline conclude that battery manufacturing in the United States will never work, or that sodium-ion itself is uncompetitive. I think both those statements are naive and lack technological nuance.”
Opinions differ on the primary advantages of sodium-ion compared to lithium-ion, but one frequently cited benefit is the potential to build a U.S.-based supply chain. Sodium is cheaper and more abundant than lithium, and China hasn’t yet secured dominance in this emerging market, though it has taken an early lead. Sodium-ion batteries also perform better at lower temperatures, have the potential to be less flammable, and — under the right market conditions — could eventually become more cost-effective than lithium-ion, which is subject to more price volatility because it’s expensive to extract and concentrated in just a few places.
Yao’s paper didn’t examine Natron’s specific technology, which relied on a cathode material known as “Prussian Blue Analogue,” as the material’s chemical structure resembles that of the pigment Prussian Blue. This formula enabled the company’s batteries to discharge large bursts of power extremely quickly while maintaining a long cycle life, making it promising for a niche — but crucial — domestic market: data center backup power.
Natron’s batteries were designed to bridge the brief gap between a power outage and a generator coming online. Today, that role is often served by lead-acid batteries, which are cheap but bulky, with a lower energy density and shorter cycle life than sodium-ion. Thus, Yao saw this market — though far smaller than that of grid-scale energy storage — as a “technologically pragmatic” opportunity for the company.
“It’s almost like a supercapacitor, not a battery,” one executive in the sodium-ion battery space who wished to remain anonymous told me of Natron’s battery. Supercapacitors are energy storage devices that — like Natron’s tech — can release large amounts of power practically immediately, but store far less total energy than batteries.
“The thing that has been disappointing about the whole story is that people talk about Natron and their products and their journey as if it’s relevant at all to the sodium-ion grid scale storage space,” the executive told me. The grid-scale market, they said, is where most companies are looking to deploy sodium-ion batteries today. “What happened to Natron, I think, is very specific to Natron.”
But what exactly did happen to the once-promising startup, which raised over $363 million in private investment from big name backers such as Khosla Ventures and Prelude Ventures? What we know for sure is that it ran out of money, canceling plans to build a $1.4 billion battery manufacturing facility in North Carolina. The company was waiting on certification from an independent safety body, which would have unleashed $25 million in booked orders, but was forced to fold before that approval came through.
Perhaps seeing the writing on the wall, Natron’s founder, Colin Wessells, stepped down as CEO last December and left the company altogether in June.
“I got bored,” Wessels told The Information of his initial decision to relinquish the CEO role. “I found as I was spending all my time on fundraising and stockholder and board management that it wasn’t all that much fun.”
It’s also worth noting, however, that according to publicly available data, the investor makeup of Natron appears to have changed significantly between the company’s $35 million funding round in 2020 and its subsequent $58 million raise in 2021, which could indicate qualms among early backers about the direction of the company going back years. That said, not all information about who invested and when is publicly known. I reached out to both Wessels and Natron’s PR team for comment but did not receive a reply.
The company submitted a WARN notice — a requirement from employers prior to mass layoffs or plant closures — to the Michigan Department of Labor and Economic Opportunity on August 28. It explained that while Natron had explored various funding avenues including follow-on investment from existing shareholders, a Series B equity round, and debt financing, none of these materialized, leaving the company unable “to cover the required additional working capital and operational expenses of the business.”
Yao told me that the startup could have simply been a victim of bad timing. “While in some ways I think the AI boom was perfect timing for Natron, I also think it might have been a couple years too early — not because it’s not needed, but because of bandwidth,” he explained. “My guess is that the biggest thing on hyperscalers’ minds are currently still just getting connected to the grid, keeping up with continuous improvements to power efficiency, and how to actually operate in an energy efficient manner.” Perhaps in this environment, hyperscalers simply viewed deploying new battery tech for a niche application as too risky, Yao hypothesized, though he doesn’t have personal knowledge of the company’s partnerships or commercial activity.
The sodium-ion executive also thought timing might have been part of the problem. “He had a good team, and the circumstances were just really tough because he was so early,” they said. Wessells founded Natron in 2012, based on his PhD research at Stanford. “Maybe they were too early, and five years from now would have been a better fit,” the executive said. “But, you know, who’s to say?”
The executive also considers it telling that Natron only had $25 million in contracts, calling this “a drop in the bucket” relative to the potential they see for sodium-ion technology in the grid-scale market. While Natron wasn’t chasing the big bucks associated with this larger market opportunity, other domestic sodium-based battery companies such as Inlyte Energy and Peak Energy are looking to deploy grid-scale systems, as are Chinese battery companies such as BYD and HiNa Battery.
But it’s certainly true that manufacturing this tech in the U.S. won’t be easy. While Chinese companies benefit from state support that can prop up the emergent sodium-ion storage industry whether it’s cost-competitive or not, sodium-ion storage companies in the U.S. will need to go head-to-head with LFP batteries on price if they want to gain significant market share. And while a few years ago experts were predicting a lithium shortage, these days, the price of lithium is about 90% off its record high, making it a struggle for sodium-ion systems to match the cost of lithium-ion.
Sodium-ion chemistry still offers certain advantages that could make it a good option in particular geographies, however. It performs better in low-temperature conditions, where lithium-ion suffers notable performance degradation. And — at least in Natron’s case — it offers superior thermal stability, meaning it’s less likely to catch fire.
Some even argue that sodium-ion can still be a cost-effective option once manufacturing ramps up due to the ubiquity of sodium, plus additional savings throughout the batteries’ useful life. Peak Energy, for example, expects its battery systems to be more expensive upfront but cheaper over their entire lifetime, having designed a passive cooling system that eliminates the need for traditional temperature control components such as pumps and fans.
Ultimately, though, Yao thinks U.S. companies should be considering sodium-ion as a “low-temperature, high-power counterpart” — not a replacement — for LFP batteries. That’s how the Chinese battery giants are approaching it, he said, whereas he thinks the U.S. market remains fixated on framing the two technologies as competitors.
“I think the safe assumption is that China will come to dominate sodium-ion battery production,” Yao told me. “They already are far ahead of us.” But that doesn’t mean it’s impossible to build out a domestic supply chain — or at least that it’s not worth trying. “We need to execute with technologically pragmatic solutions and target beachhead markets capable of tolerating cost premiums before we can play in the big leagues of EVs or [battery energy storage systems],” he said.
And that, he affirmed, is exactly what Natron was trying to do. RIP.
