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Can solar plus storage fix one of the thorniest problems of the energy transition?

To talk about renewable energy these days is to talk about power lines. “No transition without transmission” has become something of a mantra among a legion of energy wonks. And following the passage of the Inflation Reduction Act, which contains a massive pot of subsidies for non-carbon-emitting power but little in the way of delivering it, legislative and regulatory attention has turned to getting that power from where it’s sunny and windy to where it’s needed.
Hardly a day goes by in which some industry group or environmental nonprofit isn’t assaulting the inboxes of climate journalists like myself with another study or white paper stressing the need for more transmission. But I’ve also recently noticed a newer group of advocates popping up: the battery stans.
Now, virtually everyone in the renewable energy space loves talking about the massive growth and potential of batteries to store power generated by renewables for when it’s needed most. Here the Inflation Reduction Act’s honeypot of subsidies and the long economic trends are working together. The price of batteries really is falling dramatically, and their deployment has been ramped up.
For most people, batteries are a complement to transmission upgrades. But to a much smaller group, the falling prices of solar and batteries may obviate the need for transmission expansion entirely.
Let’s start with the more mild case. As Duncan Campbell, Vice President at Scale Microgrids told me, “If you go deep on power grid expansion modeling studies, they all assume an enormous build-out of transmission well beyond what we’ve done in the past and I think demonstrated to be well beyond the current institutional capacity.” In other words, you can pencil in as much transmission build-out as you want, but the chances we’ll actually do it seem at least short of certain. “It’s quite reasonable to suggest when doing something super ambitious that it’s a good idea to have a diversified approach,” he said.
That diversified approach, for Campbell, includes storage and generation both on the transmission part of the grid — like utility-scale storage paired with solar arrays — and on the distribution side of the grid, like rooftop solar and garage batteries. The latter two examples can also work together as a “virtual power plant” to modulate consumption based on when power is most expensive or cheap and even sometimes send power back to the grid at times of stress.
“At the end of the day it seems undeniably prudent to think about what solutions are going to complement large-scale transmission build-out if we want to meet these goals. Otherwise it’s a concentrated approach that carries a lot of risks,” Campbell told me. “Technologically, VPPs and DER [distributed energy resources] can help. Especially in those worst situations.”
This balanced approach would not actually face much opposition from advocates for a substantial transmission build-out, even if sometimes this “debate” — especially on Twitter, I’m sorry, especially on X — can get polarized and contentious.
“They’re complementary, not competitive,” Ric O’Connell, the executive director of GridLab, told me. “Transmission moves energy around in space, storage moves around in time. You need both.”
O’Connell pointed out that storage in some cases could be thought of a transmission asset, something analogous to the wires and poles that move electricity, where power could be moved on very short time frames to help out with extremely high levels of demand, a lack of generation, or transmission congestion. We’ve seen this already in Texas, where storage has helped take the bite out of extremely high demand recently, and in California, where it has helped alleviate the rapid disappearance of solar power every evening.
“The shorter duration storage stuff is working to address congestion and streamline transmission operations. In that sense you can put it in the same category as a grid enhancing technology,” O’Connell said.
While nearly everyone I talked to was eager to say that storage and transmission could complement each other, even if some leaned on transmission more and others were more bullish on storage and distributed energy, there was one person who actually did represent a clear and polarizing view: Casey Handmer.
Handmer is a Cal Tech trained physicist who used to write software for the Jet Propulsion Laboratory and founded Terraform Industries, an early stage start up that’s looking to develop the “Terraformer,” a solar-powered factory that would create synthetic natural gas. Immodestly, he “aims to displace the majority of fossil hydrocarbon production by 2035.”
More modestly, he describes himself as “effectively a puffed up blogger who runs a pre-revenue (i.e. default dead) startup in an area peripheral (at best) to grid issues,” but is nonetheless, again, immodestly “pretty confident that my analysis is correct,” he told me in an email.
“My views on this matter are unconventional, even controversial. Arguably this is my spiciest hot take on the future of energy,” he wrote on his blog.
He thinks that the falling price of solar and batteries will make large-scale transmission investments unnecessary.
The price declines in battery and solar will continue, allowing people and businesses to throw up solar wherever, pair it with batteries, to the point where solar is “5-15x” overbuilt. That would mean that solar wouldn’t need to be backed up by any kind of “clean firm” power, i.e. a source that can produce carbon-free electricity at any time, like nuclear power, pumped-hydro, green hydrogen, or natural gas with carbon capture and storage.
While extreme, his views are not so, so, so far off from other renewables maximalists, who view solar and battery price declines as essentially inexorable. If they’re right, resource adequacy issues (i.e. that it’s much more sunny in some places than others) could be overcome by just building more cheap solar and installing more batteries.
“Adding 12 hours of storage to the entire U.S. grid would not happen overnight, but on current trends would cost around $500 billion and pay for itself within a few years. This is a shorter timescale than the required manufacturing ramp, meaning it could be entirely privately funded. By contrast, upgrading the U.S. transmission grid could cost $7 trillion over 20 years,” Handmer wrote in July.
As for the case that transmission is needed to get solar power from where it’s sunnier (like southern Europe or the American Southwest) to where it isn’t (Northern Europe, the rest of America), Handmer argues this isn’t really a problem.
“Solar resource quality doesn't matter that much. Solar resource is much more evenly distributed than, say, oil,” he told me. “Almost all humans live close to where their grandparents were able to grow food to live, and crops only grow in places that are roughly equally sunny.” He also argued that “solar is about 1000x more productive in terms of energy produced per unit land used than agriculture,” so building it will be economically compelling in huge swathes of the world.
As he acknowledges, his view is pretty lonely. He seems to yada-yada away what developments in battery technology would be needed to make this all work (although presumably ever-cheapening solar could just charge more lithium-ion batteries). One estimate suggests that to have “the greatest impact on electricity cost and firm generation,” battery storage would have to extend out to 100 hours — about 25X more than they do now.
This is where I say what you’re already thinking. This combination of technofuturism, contrarianism, work experience in the space industry and comfort with back-of-the-envelope math to make strong assertions makes Handmer sound like — and I mean this in the most value-neutral, descriptive way possible — another proponent of the rooftop solar, home battery, electric car future: Elon Musk. (Handmer used to work at the Musk-inspired Hyperloop One).
When I asked him why he’s an admitted outlier on this, he chalked it up to “anchoring bias in the climate space ... before solar and batteries got cheap, analyses showed that increasing the size of the grid was the best way to counter wind intermittency. But when the assumptions and data change, the results change too. The future of electricity is local. As a physicist, I was trained to take unusual observations to their utmost conclusion.”
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Even though he is partially responsible for them.
This is an edition of Heatmap Daily, an evening review of the day’s news written by our executive editor. Sign up for it here.
Welcome to August — which, as the political commentator Josh Barro once observed, is the year’s “stupidest news month.” Because Congress goes on recess around this time of year, and so many other Americans go on vacation, “the quantity of serious news structurally declines,” and we journalists have to turn to sillier stories in order to fill the space.
I couldn’t help but think of that post today. As my colleague Matthew Zeitlin covered last week, oil companies recently had a blowout quarter. Last week, Chevron reported its best quarterly earnings result ever, while Exxon announced its largest profit in four years. None of this was a surprise: The Iran war and the Strait of Hormuz’s closure sent oil prices soaring around the world in the spring, making the supermajors’ domestic refinery business especially profitable. Despite its big result, Exxon actually underperformed Wall Street’s expectations — that’s how expected all of this was.
Still, though — the oil companies benefited from a supply shock that was hurting everyone else in the economy. Although this kind of volatility is part and parcel of the commodities business — it is part of what makes commodities so enticing to investors — it is, at the very least, not a good look. And in times like these, progressive policymakers will sometimes call for a windfall profits tax, a one-time levy on large and unexpected profits arising from a situation outside a company’s control. (Centrists and conservatives tend to prefer making different reforms to the tax system that tax “supernormal” profits.)
The United States last imposed a windfall profits tax on oil companies in the 1970s, but other countries still use them today: The U.K. implemented one after Russia’s invasion of Ukraine drove up gas prices in 2022, as did a handful of European countries. More recently, Senator Sheldon Whitehouse of Rhode Island and Representative Ro Khanna of California proposed a windfall tax after gasoline prices shot up in March.
I wouldn’t have counted President Trump among Whitehouse’s and Khanna’s number. Yet speaking to reporters from the Oval Office today, Trump said the oil companies were “making too much money” from the Strait of Hormuz closure.
“Chevron, too much money. ExxonMobil, too much money,” the president said. “When you look at one company where they made 12 times what they made the year before, they ought to give some of that back to the public … And they better cut the retail price, the consumer price.”
He noted that many reporters looked “surprised” he was saying it, but reiterated he “wasn’t happy.”
Now, the president hasn’t quite called for a windfall profits tax — he seems to have something more voluntary in mind. Yet given Trump’s fealty to the industry in virtually every other context, his comments are striking and make his political judgement around the war all the more perplexing. The president chose to go to war with Iran — and the almost certain outcome of that conflict, in any world, was going to be higher oil prices. If anything, the war has moved crude less than analysts would have thought. What was Trump expecting here?
I don’t expect these remarks to usher in some new era of Trumpian policy or politics — this is probably just another silly August story. But they reflect how much the politics of energy have changed since President Trump took office in January 2025. Americans know it, Democrats know it, and President Trump knows it too.
Data centers are a big test for the nascent industry. But they also can’t fill the orderbooks.
For the last few years, there’s been just one story dominating the economy, Silicon Valley, and much of the climate tech world too: artificial intelligence. It has consumed investor’s time and money, leaving relatively little for the rest of the startup ecosystem. But for companies that can hitch themselves to the AI boom and tie their value proposition to the data center buildout, this narrow funding focus can be a tailwind.
The most obvious beneficiaries so far have largely fallen into two camps: startups using AI to build cheaper, better products or those developing technologies to cleanly power data centers themselves. But what about the companies actually manufacturing the physical materials behind these facilities? The data center buildout is ultimately an investment in the physical economy, which largely means an investment in concrete — the most widely used man-made material on Earth.
Cement, the key ingredient that binds concrete together, accounts for 8% of global CO2 emissions, and is a major driver of hyperscaler’s scope 3 emissions. Microsoft and Google’s recent sustainability reports, for example, reveal that their largest emissions category isn’t electricity but “capital goods,” which includes the embodied carbon in their physical assets and infrastructure such as the concrete, steel, server racks, and silicon used to build data centers.
Cement is a big part of that picture because producing it typically requires burning limestone in kilns at extremely high temperatures, a process that both uses large amounts of fossil fuels and releases CO2 through the underlying chemical reaction itself. So if hyperscalers are serious about decarbonization, one might expect them to be pretty interested in startups such as Brimstone, Sublime Systems, and Fortera, each of which is pursuing a different approach to reducing cement’s carbon footprint.
And they are interested. But that alone won’t fill these company’s orderbooks or offset the headwinds generated by the Trump administration rescinding previously obligated grants. That challenge has only been compounded by climate tech’s broader fall from favor as investors chase flashier, more explicitly AI-centric bets.
Still, Cory Waltrip, Sublime’s VP of business development, told me that data centers make a fantastic beachhead market for the company’s low-carbon cement, which it produces through an electrochemical process that eliminates the need for high-temperature kilns. Hyperscalers, he said, have both the market power and financial runway to think long-term about “the way that they’re signing agreements” and “how you can structure those agreements.” Of course, “the balance sheet and the amount of capital that they allocate towards sustainability commitments” doesn’t hurt either.
Last May, Microsoft signed an offtake agreement with Sublime to purchase up to 622,500 metric tons of cement from the company’s future demonstration plant in Holyoke, Massachusetts, as well as a yet-to-be-sited full-scale facility. The deal is unique because it doesn’t require Microsoft to actually use Sublime’s cement in its data centers. Since cement is expensive and impractical to ship long distances, what Microsoft really purchased is the cement’s so-called “environmental attributes,” allowing Sublime to sell the physical product to local customers while Microsoft gets to claim the associated emissions reductions.
It was one of the first deals in the cement industry to decouple the physical product from its environmental benefits. But that good news was quickly overshadowed. Just eight days later, Energy Secretary Chris Wright announced the cancellation of 24 awards from the DOE’s Office of Clean Energy Demonstrations, including a $87 million grant for Sublime and a $189 million grant for Brimstone. That sent Sublime into a tailspin: In December, it paused plans for its demo plant, and in March it laid off roughly two-thirds of its workforce. The company has since filed a suit in the court of federal claims, alleging that the DOE breached its contract with Sublime, but a resolution could take years.
All the cement-hungry data centers in the world would struggle to make up for the loss of that federal funding. Hyperscalers want to buy low-carbon cement from companies that already have a credible pathway to commercial production, not foot the bill for a first-of-a-kind plant.
So Sublime is now pursuing “alternative scale up plans” that don’t involve the Holyoke facility, with Microsoft remaining “a committed customer,” Waltrip said. The most promising option involves co-locating with existing but underutilized standard cement plants in North America or Europe. Doing so could reduce capital costs by roughly 20% to 40%, Waltrip told me. “We can use all of the existing crushing, grinding, finishing, and storage equipment that an existing cement plant already has.”
Building in Europe — something Sublime has yet to commit to but is certainly considering — could also open the door to other non-dilutive public financing, such as the bloc’s roughly €40 billion EU Innovation Fund, which regularly backs industrial decarbonization projects such as low-carbon cement.
In the meantime, the company also says it’s made significant process improvements that could drastically change the scale at which it builds plants. While former CEO Leah Ellis described Sublime’s future commercial facility as a “megaton-scale plant,” Sublime now thinks it could economically produce the material in 50,000 to 250,000 metric tons-per-year facilities. These smaller plants would be far easier to finance without relying on large government grants, Waltrip told me.
Sublime is exploring multiple other undisclosed data center engagements as well, as Waltrip revealed that “we’ve completed materials testing with at least one hyperscaler. We’ve completed a concrete demonstration pour with another hyperscaler,” and “we’ve negotiated or are in the process of negotiating commercial agreements with other hyperscalers beyond Microsoft.”
The company also conducted a small test pour of its low-carbon concrete last year with STACK Infrastructure, a data center developer that leases out its facilities. But while the material has exceeded performance standards, STACK is unlikely to become a customer anytime soon. “If we had a commercial plant ready to go, I think we would be having no issues with finding customers for that product,” Waltrip told me. The challenge is that developers outside the major hyperscalers typically lack the financial flexibility to sign long-term offtake agreements for a product that may not reach meaningful scale until the mid-2030s.
So for now, Google, Microsoft, Meta, and Amazon remain the most sought-after buyers.
Brimstone, another low-carbon cement company, also landed a major hyperscaler deal last year. The company, which still uses kilns but replaces limestone with carbon-free calcium silicate rocks in its production process, agreed to supply Amazon with an undisclosed amount of cement and supplementary cementitious materials, which can partially replace cement in concrete. CEO Cody Finke told me he couldn’t share any additional details, including the volume of materials reserved or when he expects deliveries to begin, though he readily acknowledges the impact of the data center boom.
“There’s no question that the data center buildout has increased the demand for these materials,” Finke told me. Early last year, the company announced that it’s also figured out how to adapt its process to produce alumina — the refined material that smelters turn into aluminum. Data centers also use this metal throughout their operations in structural panels, server racks, and cooling systems. Eventually, the company says it will be able to make additional critical minerals and materials including steel, magnesium, and titanium.
For now though, Brimstone is working to complete construction of its demo plant in Reno, Nevada, which the company recently said it expects to be operational in 2028. Finke was somewhat more cautious, however, telling me only that it should come online by “the end of the decade.” The company’s first full-scale plant, the location of which it’s yet to announce, is slated to begin operations around 2034, producing 350,000 metric tons of alumina and an undisclosed amount of cement and other materials.
But like Sublime, Brimstone also lost a major source of federal support when the Trump administration rescinded its $189 million DOE grant, which was intended to finance construction of the demo plant. Finke, however, insisted this hasn’t altered the company’s timeline because Brimstone, having netted over $80 million to date, “had effectively raised the money that we needed, regardless of the grant.”
Finke isn’t relying on the goodwill of hyperscalers either, even though many do appear willing to pay a green premium in order to align with their ambitious, if flailing, decarbonization agendas. “To be frank, I don’t think that it’s that important to the transition whether or not those climate policies exist, because the companies that really matter are going to be cheaper anyway,” he told me.
Brimstone, he argues, is one of those companies. By co-producing multiple products at once, each can effectively offset the cost of the others, and Finke expects even the cement produced at the Reno demo plant to sell at standard market rates. Ultimately, while he sees growth in the data center industry as a tailwind, he doesn’t think Brimstone depends on that market, noting these facilities still only account for a small sliver of global cement demand. The company’s primary customers, he said, will ultimately be traditional buyers: concrete producers purchasing cement and aluminum smelters buying alumina.
Yet data centers willing to negotiate multi-year contracts still represent uniquely valuable first customers in an industry where such agreements are exceedingly rare. Instead, producers typically sell cement into a merchant spot market, where buyers purchase from whatever supplier meets their myriad requirements at the time. But that leaves low-carbon materials startups in a bind, Fortera’s CEO Ryan Gilliam told me. “When you’re trying to bring a new technology to market like us, you typically use offtake agreements to get project financing to justify building up big projects,” he explained. Potential investors simply want to see demonstrated future demand.
Fortera, which has raised about $150 million and has an operational pilot plant in California, captures the CO2 emitted from conventional cement production and converts it into a mineral form that then becomes part of the cement itself. Last year, it secured a strategic investment from Microsoft’s Climate Innovation Fund to help finance its first commercial-scale facility, expected to produce 400,000 tons of cement per year. In return, the tech giant secured the right to procure Fortera’s low-carbon cement and its associated environmental attribute certificates — more of a reservation than the binding offtake contract it signed with Sublime.
Just one plant of this size “would meet all the hyperscalers’ needs easily,” Gilliam told me, underlining Finke’s point that data centers will by no means represent a cement company’s largest buyer long-term. “Most hyperscalers, you’re talking maybe upwards of 100,000 tons a year of requirements around cement, and that might even be at the upper end,” Gilliam explained. By comparison, standard cement plants typically produce about a million tons of product annually.
So while Gilliam and others are happy to ride the AI boom, they also recognize that data centers are likely more valuable as an early market signal than a long-term source of demand. Even now, it remains unclear whether the boom is even a net positive for the sector as a whole.
“The number of AI startups and the amount of money that’s been diverted into that space definitely changed the pool of investors that you can go to right now,” Gilliam told me. And that’s the core paradox. The data center boom has become one of the clean cement industry’s most promising early markets and one of its fiercest competitors for capital. Welcome to the AI economy.
The energy developer is backing off after a Heatmap report.
Clearway says it is backing off its plans to build a data center and gas power plant on federal land, days after Heatmap revealed the energy developer’s proposal.
Last week, I reported that Clearway asked the Trump administration’s Bureau of Land Management to swap a five year-old application for a solar farm’s permits with “a proposed data center and natural gas facility.” Clearway’s chief development officer John Woody had written in a letter to BLM dated April 3 that the swap was “the result of a shift in our internal development priorities” and intended “to better align with the goals of our Administration.” He also noted the plans were in “exploratory early stages.”
This news fit a trend. I obtained Clearway’s letter right after reporting on a different solar project on federal land that was being swapped for a data center. But it turns out, the company’s internal thinking continued to shift: on Friday, they reached out to me saying they are now nixing the data center and gas plant, after concluding it wasn’t the right call for their business.
“Since our initial filing, we’ve evaluated how to make the best use of this public land in a way that serves its intended purpose: the public interest. As a clean energy developer and operator, our focus in Nevada remains solar and battery storage,” Clearway said in a statement it provided to me from an unnamed spokesperson. “We are in the process of amending our application to reflect the state’s growing demand for low-cost, reliable energy.”
In addition, Clearway on Monday sent a letter to BLM formally alerting the agency it has no plans to build the data center, which it also provided to me.
When I first broke news of Clearway’s plans, I said it was an apparent aberration – they oversaw relatively few fossil projects and had never worked in data centers. I chalked this pivot up to yet another energy developer changing its tune with the winds of national politics. Now that the company is apparently sticking to its guns, I’m mostly just left wondering what happened here – and relieved some still remain committed to zero-emissions power in the booming business of electrons.