In defense of air-conditioning

I’ll admit that I’ve rarely hesitated to point an accusing finger at air-conditioning. I’ve outlined in many stories and newsletters that AC is a significant contributor to global electricity demand, and it’s only going to suck up more power as temperatures rise.

But I’ll also be the first to admit that it can be a life-saving technology, one that may become even more necessary as climate change intensifies. And in the wake of Europe’s recent deadly heat wave, it’s been oddly villainized

We should all be aware of the growing electricity toll of air-conditioning, but the AC hate is misplaced. Yes, AC is energy intensive, but so is heating our homes, something that’s rarely decried in the same way that cooling is. Both are tools for comfort and, more important, for safety.  So why is air-conditioning cast as such a villain?

In the last days of June and the first few days of July, temperatures hit record highs across Europe. Over 2,300 deaths during that period were attributed to the heat wave, according to early research from World Weather Attribution, an academic collaboration that studies extreme weather. And human-caused climate change accounted for 1,500 of the deaths, the researchers found. (That is, the number of fatalities would have been under 800 if not for higher temperatures because of climate change.)

We won’t have the official death toll for months, but these early figures show just how deadly heat waves can be. Europe is especially vulnerable, because in many countries, particularly in the northern part of the continent, air-conditioning is not common.

Popping on a fan, drawing the shades, or opening the windows on the hottest days used to cut it in many European countries. Not anymore. The UK was 1.24 °C (2.23 °F) warmer over the past decade than it was between 1961 and 1990, according to the Met Office, the UK’s national climate and weather service. One recent study found that homes across the country are uncomfortably or dangerously warm much more frequently than they used to be.

The reality is, some parts of the world are seeing an upward shift in temperatures that’s not just uncomfortable but dangerous. As a result, air-conditioning usage is going up all over the world, including in countries with historically low rates.

The reaction to this long-term trend, especially in the face of the recent heat wave, has been apoplectic. People are decrying AC across social media and opinion pages, arguing that we need to suck it up and deal with being a little bit uncomfortable.

Now, let me preface this by saying that I do live in the US, where roughly 90% of homes are cooled with air-conditioning today. So perhaps I am a little biased in favor of AC. But it baffles me when people talk about air-conditioning this way.

I spent a good amount of my childhood in the southeastern US, where it’s very obvious that heat can be dangerous. I was used to many days where temperatures were well above 90 °F (32 °C), and the humidity was so high your clothes would stick to you as soon as you stepped outdoors. 

For some people, being active or working in those conditions can lead to heatstroke. Prolonged exposure, even if it’s not immediately harmful, can lead to heart and kidney problems. Older people, children, and those with chronic conditions can be more vulnerable

In other words, air-conditioning is more than a convenience; in certain conditions, it’s a safety measure. That should be an easy enough concept to grasp. After all, in many parts of the world we expect access to heating in the name of safety. Nobody wants to freeze to death. 

And it’s important to clarify here that while air-conditioning does use a lot of electricity in the US, heating actually has a higher energy footprint. 

In the US, about 19% of residential electricity use goes to air-conditioning. That sounds like a lot, and it’s significantly more than the 12% of electricity that goes to space heating. However, we need to zoom out to get the full picture, because electricity makes up only part of a home’s total energy demand. A lot of homes in the US use natural gas for heating—that’s not counted in the electricity being used, but it’s certainly part of the home’s total energy use.

When we look at the total, space heating accounts for a full 42% of residential energy consumption in the US, while air conditioning accounts for only 9%.

I’m not letting AC off the hook entirely here. There’s obviously a difference between running air-conditioning (or other, less energy-intensive technologies) when needed to stay safe and blasting systems at max capacity because you prefer it chilly. And there’s a lot of grid planning we’ll need to do to make sure we can handle the expected influx of air-conditioning around the globe. 

But the world is changing, and temperatures are rising. If you’re looking for a villain, look beyond the air conditioner and into the atmosphere.

This article is from The Spark, MIT Technology Review’s weekly climate newsletter. To receive it in your inbox every Wednesday, sign up here.

California is set to become the first US state to manage power outages with AI

California’s statewide power grid operator is poised to become the first in North America to deploy artificial intelligence to manage outages, MIT Technology Review has learned. 

“We wanted to modernize our grid operations. This fits in perfectly with that,” says Gopakumar Gopinathan, a senior advisor on power system technologies at the California Independent System Operator—known as the CAISO and pronounced KAI-so. “AI is already transforming different industries. But we haven’t seen many examples of it being used in our industry.” 

At the DTECH Midwest utility industry summit in Minneapolis on July 15, CAISO is set to announce a deal to run a pilot program using new AI software called Genie, from the energy-services giant OATI. The software uses generative AI to analyze and carry out real-time analyses for grid operators and comes with the potential to autonomously make decisions about key functions on the grid, a switch that might resemble going from uniformed traffic officers to sensor-equipped stoplights. 

But while CAISO may deliver electrons to cutting-edge Silicon Valley companies and laboratories, the actual task of managing the state’s electrical system is surprisingly analog. 

Today, CAISO engineers scan outage reports for keywords about maintenance that’s planned or in the works, read through the notes, and then load each item into the grid software system to run calculations on how a downed line or transformer might affect power supply.

“Even if it takes you less than a minute to scan one on average, when you amplify that over 200 or 300 outages, it adds up,” says Abhimanyu Thakur, OATI’s vice president of platforms, visualization, and analytics. “Then different departments are doing it for their own respective keywords. Now we consolidate all of that into a single dictionary of keywords and AI can do this scan and generate a report proactively.” 

If CAISO finds that Genie produces reliable, more efficient data analyses for managing outages, Gopinathan says, the operator may consider automating more functions on the grid. “After a few rounds of testing, I think we’ll have an idea about what is the right time to call it successful or not,” he says. 

Regardless of the outcome, the experiment marks a significant shift. Most grid operators are using the same systems that utilities have used “for decades,” says Richard Doying, who spent more than 20 years as a top executive at the Midcontinent Independent System Operator, the grid operator for an area encompassing 15 states from the upper Midwest down to Louisiana. 

“These organizations are carved up for people working on very specific, specialized tasks and using their own proprietary tools that they’ve developed over time,” says Doying, now a vice president at the consultancy Grid Strategies. “To the extent that some of these new AI tools are able to draw from data across different areas of an organization and conduct more sophisticated analysis, that’s only helpful for grid operators.”

Last year, a Department of Energy report found that AI had potential to speed up studies on grid capacity and transmission, improve weather forecasting to help predict how much energy wind and solar plants would produce at a given time, and optimize planning for electric-vehicle charging networks. Another report by the energy department’s Loan Programs Office concluded that adding more “advanced” technology such as sensors to various pieces of equipment will generate data that can enable AI to do much more over time. 

In April, the PJM Interconnection—the nation’s largest grid system, spanning 13 states along the densely populated mid-Atlantic and Eastern Seaboard—took a big step toward embracing AI by inking a deal with Google to use its Tapestry software to improve regional planning and speed up grid connections for new power generators. 

ERCOT, the Texas grid system, is considering adopting technology similar to what CAISO is now set to use, according to a source with knowledge of the plans who requested anonymity because they were not authorized to speak publicly. ERCOT did not respond to a request for comment. 

Australia offers an example of what the future may look like. In New South Wales, where grid sensors and smart technology are more widely deployed, AI software rolled out in February is now predicting the production and flow of electricity from rooftop solar units across the state and automatically adjusting how much power from those panels can enter the grid. 

Until now, much of the discussion around AI and energy has focused on the electricity demands of AI data centers (check out MIT Technology Review’s Power Hungry series for more on this).

“We’ve been talking a lot about what the grid can do for AI and not nearly as much about what AI can do for the grid,” says Charles Hua, a coauthor of one of last year’s Energy Department reports who now serves executive director of PowerLines, a nonprofit that advocates for improving the affordability and reliability of US grids. “In general, there’s a huge opportunity for grid operators, regulators, and other stakeholders in the utility regulatory system to use AI effectively and harness it for a more resilient, modernized, and strengthened grid.” 

For now, Gopinathan says, he’s remaining cautiously optimistic. 

“I don’t want to overhype it,” he says. 

Still, he adds, “it’s a first step for bigger automation.”

“Right now, this is more limited to our outage management system. Genie isn’t talking to our other parts yet,” he says. “But I see a world where AI agents are able to do a lot more.”

China’s energy dominance in three charts

China is the dominant force in next-generation energy technologies today. It’s pouring hundreds of billions of dollars into putting renewable sources like wind and solar on its grid, manufacturing millions of electric vehicles, and building out capacity for energy storage, nuclear power, and more. This investment has been transformational for the country’s economy and has contributed to establishing China as a major player in global politics. 

Meanwhile, in the US, a massive new tax and spending bill just cut hundreds of billions in credits, grants, and loans for clean energy technologies. It’s a stark reversal from previous policies, and it could have massive effects at a time when it feels as if everyone is chasing China on energy.

So while we all try to get our heads around what’s next for climate tech in the US and beyond, let’s look at just how dominant China is when it comes to clean energy, as documented in three charts.

China is on an absolute tear installing wind and solar power. The country reached nearly 900 gigawatts of installed capacity for solar at the end of 2024, and the rapid pace of building has continued into this year. An additional 198 GW was installed between January and May, with 93 GW coming in May alone

For context, those additions over the first five months of the year account for more than double the capacity of the grid in California. Not the renewables capacity of that state—the entire grid. 

Meanwhile, the policy shift in the US is projected to slow down new solar and wind additions. With tax credits and other support stripped away, much of the new capacity that was expected to come online by the end of the decade will now face delays or cancellations. 

That’s significant because of all the new electricity generation capacity that’s come online in the US recently, renewables make up the vast majority. Solar and battery storage alone are expected to make up over 80% of capacity additions in 2025. So slowing down wind and solar basically means slowing down adding new electricity capacity, at a time when demand is very much set to rise. (Hello, AI?)

China’s EV market is also booming—the country is currently flirting with a big symbolic milestone, nearing the point where over half of all new vehicles sold in the country are electric. (It already passed that mark for a single month and could do so on a yearly basis in the next couple of years.)

It’s not just selling those vehicles within China, either: the country exports them globally, with customers including established markets like Europe and growing ones like India and Brazil. As of 2024, more than 70% of electric and plug-in hybrid vehicles on roads around the world were built in ChinaSome leaders in legacy automakers are taking notice. Ford CEO Jim Farley shared some striking comments at the Aspen Ideas Festival last month about how far ahead China is on vehicle technology and price. “They have far superior in-vehicle technology,” Farley said. “We are in a global competition with China, and it’s not just EVs. And if we lose this, we do not have a future Ford.” 

Looking ahead, China is still pouring money into renewables, storage, grids, and energy efficiency technologies. It’s also outspending the rest of the world on nuclear power. The country tripled its investment in renewable power from 2015 to 2025.

The situation isn’t set in stone, though: The US actually very briefly overtook China on battery investments over the past year, as Cat Clifford at Cipher reported last week. But changes resulting from the new bill could very quickly reverse that progress, cementing China as the place for battery manufacturing and innovation.

In a story earlier this week, the MIT economist David Autor laid out the high stakes for this race. Advanced manufacturing and technology are beneficial for US prosperity, and putting public support and trade protections in place for key industries could be crucial to keeping them going, he says.  

I’d add that this whole discussion shouldn’t be about a zero-sum competition between the US and China. But many experts argue that the US, where I and many readers live, is surrendering its leadership and ability to develop key energy technologies of the future.  

Ultimately, the numbers don’t lie: By a lot of measures, China is the world’s leader in energy. The question is, will that change anytime soon?  

This article is from The Spark, MIT Technology Review’s weekly climate newsletter. To receive it in your inbox every Wednesday, sign up here.

Google’s electricity demand is skyrocketing

We got two big pieces of energy news from Google this week. The company announced that it’s signed an agreement to purchase electricity from a fusion company’s forthcoming first power plant. Google also released its latest environmental report, which shows that its energy use from data centers has doubled since 2020.

Taken together, these two bits of news offer a fascinating look at just how desperately big tech companies are hunting for clean electricity to power their data centers as energy demand and emissions balloon in the age of AI. Of course, we don’t know exactly how much of this pollution is attributable to AI because Google doesn’t break that out. (Also a problem!) So, what’s next and what does this all mean? 

Let’s start with fusion: Google’s deal with Commonwealth Fusion Systems is intended to provide the tech giant with 200 megawatts of power. This will come from Commonwealth’s first commercial plant, a facility planned for Virginia that the company refers to as the Arc power plant. The agreement represents half its capacity.

What’s important to note here is that this power plant doesn’t exist yet. In fact, Commonwealth still needs to get its Sparc demonstration reactor, located outside Boston, up and running. That site, which I visited in the fall, should be completed in 2026.

(An aside: This isn’t the first deal between Big Tech and a fusion company. Microsoft signed an agreement with Helion a couple of years ago to buy 50 megawatts of power from a planned power plant, scheduled to come online in 2028. Experts expressed skepticism in the wake of that deal, as my colleague James Temple reported.)

Nonetheless, Google’s announcement is a big moment for fusion, in part because of the size of the commitment and also because Commonwealth, a spinout company from MIT’s Plasma Science and Fusion Center, is seen by many in the industry as a likely candidate to be the first to get a commercial plant off the ground. (MIT Technology Review is owned by MIT but is editorially independent.)

Google leadership was very up-front about the length of the timeline. “We would certainly put this in the long-term category,” said Michael Terrell, Google’s head of advanced energy, in a press call about the deal.

The news of Google’s foray into fusion comes just days after the tech giant’s release of its latest environmental report. While the company highlighted some wins, some of the numbers in this report are eye-catching, and not in a positive way.

Google’s emissions have increased by over 50% since 2019, rising 6% in the last year alone. That’s decidedly the wrong direction for a company that’s set a goal to reach net-zero greenhouse-gas emissions by the end of the decade.

It’s true that the company has committed billions to clean energy projects, including big investments in next-generation technologies like advanced nuclear and enhanced geothermal systems. Those deals have helped dampen emissions growth, but it’s an arguably impossible task to keep up with the energy demand the company is seeing.

Google’s electricity consumption from data centers was up 27% from the year before. It’s doubled since 2020, reaching over 30 terawatt-hours. That’s nearly the annual electricity consumption from the entire country of Ireland.

As an outsider, it’s tempting to point the finger at AI, since that technology has crashed into the mainstream and percolated into every corner of Google’s products and business. And yet the report downplays the role of AI. Here’s one bit that struck me:

“However, it’s important to note that our growing electricity needs aren’t solely driven by AI. The accelerating growth of Google Cloud, continued investments in Search, the expanding reach of YouTube, and more, have also contributed to this overall growth.”

There is enough wiggle room in that statement to drive a large electric truck through. When I asked about the relative contributions here, company representative Mara Harris said via email that they don’t break out what portion comes from AI. When I followed up asking if the company didn’t have this information or just wouldn’t share it, she said she’d check but didn’t get back to me.

I’ll make the point here that we’ve made before, including in our recent package on AI and energy: Big companies should be disclosing more about the energy demands of AI. We shouldn’t be guessing at this technology’s effects.

Google has put a ton of effort and resources into setting and chasing ambitious climate goals. But as its energy needs and those of the rest of the industry continue to explode, it’s obvious that this problem is getting tougher, and it’s also clear that more transparency is a crucial part of the way forward.

This article is from The Spark, MIT Technology Review’s weekly climate newsletter. To receive it in your inbox every Wednesday, sign up here.

This battery recycling company is now cleaning up AI data centers

In a sandy industrial lot outside Reno, Nevada, rows of battery packs that once propelled electric vehicles are now powering a small AI data center.

Redwood Materials, one of the US’s largest battery recycling companies, showed off this array of energy storage modules, sitting on cinder blocks and wrapped in waterproof plastic, during a press tour at its headquarters on June 26. 

The event marked the launch of the company’s new business line, Redwood Energy, which will initially repurpose (rather than recycle) batteries with years of remaining life to create renewable-powered microgrids. Such small-scale energy systems can operate on or off the larger electricity grid, providing electricity for businesses or communities.

Redwood Materials says many of the batteries it takes in for processing retain more than half their capacity. 

“We can extract a lot more value from that material by using it as an energy storage project before recycling it,” JB Straubel, Redwood’s founder and chief executive, said at the event. 

This first microgrid, housed at the company’s facility in the Tahoe Reno Industrial Center, is powered by solar panels and capable of generating 64 megawatt-hours of electricity, making it one of the nation’s largest such systems. That power flows to Crusoe, a cryptocurrency miner that pivoted into developing AI data centers, which has built a facility with 2,000 graphics processing units adjacent to the lot of repurposed EV batteries. 

(That’s tiny as modern data centers go: Crusoe is developing a $500 billion AI data center for OpenAI and others in Abilene, Texas, where it expects to install 100,000 GPUs across its first two facilities by the end of the year, according to Forbes.)

Redwood’s project underscores a growing interest in powering data centers partially or entirely outside the electric grid. Not only would such microgrids be quicker to build than conventional power plants, but consumer ratepayers wouldn’t be on the hook for the cost of new grid-connected power plants developed to serve AI data centers. 

Since Redwood’s batteries are used, and have already been removed from vehicles, the company says its microgrids should also be substantially cheaper than ones assembled from new batteries.

A close up of grid of battery packs from Redwood Materials.

COURTESY REDWOOD MATERIALS

Redwood Energy’s microgrids could generate electricity for any kind of operation. But the company stresses they’re an ideal fit for addressing the growing energy needs and climate emissions of data centers. The energy consumption of such facilities could double by 2030, mainly due to the ravenous appetite of AI, according to an April report by the International Energy Agency.

“Storage is this perfectly positioned technology, especially low-cost storage, to attack each of those problems,” Straubel says.

The Tahoe Reno Industrial Center is the epicenter of a data center development boom in northern Nevada that has sparked growing concerns about climate emissions and excessive demand for energy and water, as MIT Technology Review recently reported.

Straubel says the litany of data centers emerging around it “would be logical targets” for its new business line, but adds there are growth opportunities across the expanding data center clusters in Texas, Virginia, and the Midwest as well.

“We’re talking to a broad cross section of those companies,” he says.

Crusoe, which also provides cloud services, recently announced a joint venture with the investment firm Engine No. 1 to provide “powered data center real estate solutions” to AI companies by constructing 4.5 gigawatts of new natural-gas plants.

Redwood’s microgrid should provide more than 99% of the electricity Crusoe’s local facilities need. In the event of extended periods with little sunlight, a rarity in the Nevada desert, the company could still draw from the standard power grid.

Cully Cavness, cofounder and operating chief of Crusoe, says the company is already processing AI queries and producing conclusions for its customers at the Nevada facility. (Its larger data centers are dedicated to the more computationally intensive process of training AI models.)

Redwood’s new business division offers a test case for a strategy laid out in a paper late last year, which highlighted the potential for solar-powered microgrids to supply the energy that AI data centers need.

The authors of that paper found that microgrids could be built much faster than natural-gas plants and would generally be only a little more expensive as an energy source for data centers, so long as the facilities could occasionally rely on natural-gas generators to get them through extended periods of low sunlight.

If solar-powered microgrids were used to power 30 gigawatts of new AI data centers, with just 10% backup from natural gas, it would eliminate 400 million tons of carbon dioxide emissions relative to running the centers entirely on natural gas, the study found. 

“Having a data center running off solar and storage is more or less what we were advocating for in our paper,” says Zeke Hausfather, climate lead at the payments company Stripe and a coauthor of the paper. He hopes that Redwood’s new microgrid will establish that “these sorts of systems work in the real world” and encourage other data center developers to look for similar solutions. 

Redwood Materials says electric vehicles are its fastest-growing source of used batteries, and it estimates that more than 100,000 EVs will come off US roads this year.

The company says it tests each battery to determine whether it can be reused. Those that qualify will be integrated into its modular storage systems, which can then store up energy from wind and solar installations or connect to the grid. As those batteries reach the end of their life, they’ll be swapped out of the microgrids and moved into the company’s recycling process. 

Redwood says it already has enough reusable batteries to build a gigawatt-hour’s worth of microgrids, capable of powering a little more than a million homes for an hour. In addition, the company’s new division has begun designing microgrids that are 10 times larger than the one it unveiled this week.

Straubel expects Redwood Energy to become a major business line, conceivably surpassing the company’s core recycling operation someday.

“We’re confident this is the lowest-cost solution out there,” he says.

It’s officially summer, and the grid is stressed

It’s crunch time for the grid this week. As I’m writing this newsletter, it’s 100 °F (nearly 38 °C) here in New Jersey, and I’m huddled in the smallest room in my apartment with the shades drawn and a single window air conditioner working overtime.  

Large swaths of the US have seen brutal heat this week, with multiple days in a row nearing or exceeding record-breaking temperatures. Spain recently went through a dramatic heat wave too, as did the UK, which is unfortunately bracing for another one soon. As I’ve been trying to stay cool, I’ve had my eyes on a website tracking electricity demand, which is also hitting record highs. 

We rely on electricity to keep ourselves comfortable, and more to the point, safe. These are the moments we design the grid for: when need is at its very highest. The key to keeping everything running smoothly during these times might be just a little bit of flexibility. 

While heat waves happen all over the world, let’s take my local grid as an example. I’m one of the roughly 65 million people covered by PJM Interconnection, the largest grid operator in the US. PJM covers Virginia, West Virginia, Ohio, Pennsylvania, and New Jersey, as well as bits of a couple of neighboring states.

Earlier this year, PJM forecast that electricity demand would peak at 154 gigawatts (GW) this summer. On Monday, just a few days past the official start of the season, the grid blew past that, averaging over 160 GW between 5 p.m. and 6 p.m. 

The fact that we’ve already passed both last year’s peak and this year’s forecasted one isn’t necessarily a disaster (PJM says the system’s total capacity is over 179 GW this year). But it is a good reason to be a little nervous. Usually, PJM sees its peak in July or August. As a reminder, it’s June. So we shouldn’t be surprised if we see electricity demand creep to even higher levels later in the summer.

It’s not just PJM, either. MISO, the grid that covers most of the Midwest and part of the US South, put out a notice that it expected to be close to its peak demand this week. And the US Department of Energy released an emergency order for parts of the Southeast, which allows the local utility to boost generation and skirt air pollution limits while demand is high.

This pattern of maxing out the grid is only going to continue. That’s because climate change is pushing temperatures higher, and electricity demand is simultaneously swelling (in part because of data centers like those that power AI). PJM’s forecasts show that the summer peak in 2035 could reach nearly 210 GW, well beyond the 179 GW it can provide today. 

Of course, we need more power plants to be built and connected to the grid in the coming years (at least if we don’t want to keep ancient, inefficient, expensive coal plants running, as we covered last week). But there’s a quiet strategy that could limit the new construction needed: flexibility.

The power grid has to be built for moments of the absolute highest demand we can predict, like this heat wave. But most of the time, a decent chunk of capacity that exists to get us through these peaks sits idle—it only has to come online when demand surges. Another way to look at that, however, is that by shaving off demand during the peak, we can reduce the total infrastructure required to run the grid. 

If you live somewhere that’s seen a demand crunch during a heat wave, you might have gotten an email from your utility asking you to hold off on running the dishwasher in the early evening or to set your air conditioner a few degrees higher. These are called demand response programs. Some utilities run more organized programs, where utilities pay customers to ramp down their usage during periods of peak demand.

PJM’s demand response programs add up to almost eight gigawatts of power—enough to power over 6 million homes. With these programs, PJM basically avoids having to fire up the equivalent of multiple massive nuclear power plants. (It did activate these programs on Monday afternoon during the hottest part of the day.)

As electricity demand goes up, building in and automating this sort of flexibility could go a long way to reducing the amount of new generation needed. One report published earlier this year found that if data centers agreed to have their power curtailed for just 0.5% of the time (around 40 hours out of a year of continuous operation), the grid could handle about 18 GW of new power demand in the PJM region without adding generation capacity. 

For the whole US, this level of flexibility would allow the grid to take on an additional 98 gigawatts of new demand without building any new power plants to meet it. To give you a sense of just how significant that would be, all the nuclear reactors in the US add up to 97 gigawatts of capacity.

Tweaking the thermostat and ramping down data centers during hot summer days won’t solve the demand crunch on their own, but it certainly won’t hurt to have more flexibility.

This article is from The Spark, MIT Technology Review’s weekly climate newsletter. To receive it in your inbox every Wednesday, sign up here.

The Debrief: Power and energy

It may sound bluntly obvious, but energy is power. Those who can produce it, especially lots of it, get to exert authority in all sorts of ways. It brings revenue and enables manufacturing, data processing, transportation, and military might. Energy resources are arguably a nation’s most important asset. Look at Russia, or Saudi Arabia, or China, or Canada, or Qatar, or—for that matter—the US. For all these nations, energy production plays key roles in their economies and their outsize global status. (Qatar, for example, has a population roughly the size of metro Portland, Oregon.) 

The US has always been a nation of energy and industry. It was a major producer of coal, which fed the Industrial Revolution. World War II was won in large part by the energy production in the United States—which fueled both manufacturing of the war machine at home and its ships, planes, and tanks in the Pacific and Europe. Throughout its history, the country has found strength in energy production. 

Yet in many ways right now the US seems to be forgetting those lessons. It is moving backward in terms of its clean-­energy strategy, especially when it comes to powering the grid, in ways that will affect the nation for decades to come—even as China and others are surging forward. And that retreat is taking place just as electricity demand and usage are growing again after being flat for nearly two decades. That growth, according to the US Energy Information Administration, is “coming from the commercial sector, which includes data centers, and the industrial sector, which includes manufacturing establishments.” 

As MIT Technology Review has extensively reported, energy demand from data centers is set to soar, not plateau, as AI inhales ever more electricity from the grid. As my colleagues James O’Donnell and Casey Crownhart reported, by 2028 the share of US electricity going to power data centers may triple. (For the full report, see technologyreview.com/energy-ai.)

Both manufacturing and data centers are obviously priorities for the US writ large and the Trump administration in particular. Given those priorities, it’s surprising to see the administration and Congress making moves that would both decrease our potential energy supply and increase demand by lowering efficiency. 

This will be most true for electricity generation. The administration’s proposed budget, still being considered as we went to press, would roll back tax credits for wind, solar, and other forms of clean energy. In households, they would hit credits for rooftop solar panels and residential energy efficiency programs. Simultaneously, the US is trying to roll back efficiency standards for household appliances. These standards are key to keeping consumer electricity prices down by decreasing demand. 

In short, what most analysts are expecting is more strain on the grid, which means prices will go up for everyone. Meanwhile, rollbacks to the Inflation Reduction Act and to credits for advanced manufacturing mean that fewer future-facing energy sources will be built. 

This is just belligerently shortsighted. 

That’s especially true because as the US takes steps to make energy less abundant and more expensive, China—our ostensible chief international antagonist—is moving in exactly the opposite direction. The country has made massive strides in renewable energy generation, hitting its goals six years ahead of schedule. In fact, China is now producing so much clean energy that its carbon dioxide emissions are declining as a result.

This issue is about power, in all its forms. Yet whether you’re talking about the ability to act or the act of providing electricity, power comes from energy. So when it comes to energy, we need “ands,” not “ors.” We need nuclear and solar and wind and hydropower and hydrogen and geothermal and batteries on the grid. And we need efficiency. And yes, we even need oil and gas in the mid term while we ramp up cleaner sources. That is the way to maintain and increase our prosperity, and the only way we can possibly head off some of the worst consequences of climate change.

Inside the US power struggle over coal

Coal power is on life support in the US. It used to carry the grid with cheap electricity, but now plants are closing left and right.

There are a lot of potential reasons to let coal continue its journey to the grave. Carbon emissions from coal plants are a major contributor to climate change. And those facilities are also often linked with health problems in nearby communities, as reporter Alex Kaufman explored in a new feature story on Puerto Rico’s only coal-fired power plant.

But the Trump administration wants to keep coal power alive, and the US Department of Energy recently ordered some plants to stay open past their scheduled closures. Here’s why there’s a power struggle over coal.

Coal used to be king in the US, but the country has dramatically reduced its dependence on the fuel over the past two decades. It accounted for about 20% of the electricity generated in 2024, down from roughly half in 2000.

While the demise of coal has been great for US emissions, the real driver is economics. Coal used to be the cheapest form of electricity generation around, but the fracking boom handed that crown to natural gas over a decade ago. And now, even cheaper wind and solar power is coming online in droves.

Economics was a major factor in the planned retirement of the J.H. Campbell coal plant in Michigan, which was set to close at the end of May, Dan Scripps, chair of the Michigan Public Service Commission, told the Washington Post.

Then, on May 23, US Energy Secretary Chris Wright released an emergency order that requires the plant to remain open. Wright’s order mandates 90 more days of operation, and the order can be extended past that, too. It states that the goal is to minimize the risk of blackouts and address grid security issues before the start of summer.

The DOE’s authority to require power plants to stay open is something that’s typically used in emergencies like hurricanes, rather than in response to something as routine as … seasons changing. 

It’s true that there’s growing concern in the US about meeting demand for electricity, which is rising for the first time after being basically flat for decades. (The recent rise is in large part due to massive data centers, like those needed to run AI. Have I mentioned we have a great package on AI and energy?)

And we are indeed heading toward summer, which is when the grid is stretched to its limits. In the New York area, the forecast high is nearly 100 °F (38 °C) for several days next week—I’ll certainly have my air conditioner on, and I’m sure I’ll soon be getting texts asking me to limit electricity use during times of peak demand.

But is keeping old coal plants open the answer to a stressed grid?

It might not be the most economical way forward. In fact, in almost every case today, it’s actually cheaper to build new renewables capacity than to keep existing coal plants running in the US, according to a 2023 report from Energy Innovation, an energy think tank. And coal is only getting more expensive—in an updated analysis, Energy Innovation found that three-quarters of coal plants saw costs rising faster than inflation between 2021 and 2024.

Granted, solar and wind aren’t always available, while coal plants can be fired up on demand. And getting new projects built and connected to the grid will take time (right now, there’s a huge backlog of renewable projects waiting in the interconnection queue). But some experts say we actually don’t need new generation that urgently anyway, if big electricity users can be flexible with their demand

And we’re already seeing batteries come to the rescue on the grid at times of stress. Between May 2024 and April 2025, US battery storage capacity increased by about 40%. When Texas faced high temperatures last month, batteries did a lot to help the state make it through without blackouts, as this Bloomberg story points out. Costs are falling, too; prices are about 19% lower in 2024 than they were in 2023. 

Even as the Trump administration is raising concerns about grid reliability, it’s moved to gut programs designed to get more electricity generation and storage online, like the tax credits that support wind, solar, and battery production and installation. 

This article is from The Spark, MIT Technology Review’s weekly climate newsletter. To receive it in your inbox every Wednesday, sign up here.

These new batteries are finding a niche

Lithium-ion batteries have some emerging competition: Sodium-based alternatives are starting to make inroads.

Sodium is more abundant on Earth than lithium, and batteries that use the material could be cheaper in the future. Building a new battery chemistry is difficult, mostly because lithium is so entrenched. But, as I’ve noted before, this new technology has some advantages in nooks and crannies. 

I’ve been following sodium-ion batteries for a few years, and we’re starting to see the chemistry make progress, though not significantly in the big category of electric vehicles. Rather, these new batteries are finding niches where they make sense, especially in smaller electric scooters and large energy storage installations. Let’s talk about what’s new for sodium batteries, and what it’ll take for the chemistry to really break out.

Two years ago, lithium prices were, to put it bluntly, bonkers. The price of lithium hydroxide (an ingredient used to make lithium-ion batteries) went from a little under $10,000 per metric ton in January 2021 to over $76,000 per metric ton in January 2023, according to data from Benchmark Mineral Intelligence.

More expensive lithium drives up the cost of lithium-ion batteries. Price spikes, combined with concerns about potential shortages, pushed a lot of interest in alternatives, including sodium-ion.

I wrote about this swelling interest for a 2023 story, which focused largely on vehicle makers in China and a few US startups that were hoping to get in on the game.

There’s one key point to understand here. Sodium-based batteries will need to be cheaper than lithium-based ones to have a shot at competing, especially for electric vehicles, because they tend to be worse on one key metric: energy density. A sodium-ion battery that’s the same size and weight as a lithium-ion one will store less energy, limiting vehicle range.

The issue is, as we’ve seen since that 2023 story, lithium prices—and the lithium-ion battery market—are moving targets. Prices for precursor materials have come back down since the early 2023 peak, with lithium hydroxide crossing below $9,000 per metric ton recently.

And as more and more battery factories are built, costs for manufactured products come down too, with the average price for a lithium-ion pack in 2024 dropping 20%—the biggest annual decrease since 2017, according to BloombergNEF.

I wrote about this potential difficulty in that 2023 story: “If sodium-ion batteries are breaking into the market because of cost and material availability, declining lithium prices could put them in a tough position.”

One researcher I spoke with at the time suggested that sodium-ion batteries might not compete directly with lithium-ion batteries but could instead find specialized uses where the chemistry made sense. Two years later, I think we’re starting to see what those are.

One growing segment that could be a big win for sodium-ion: electric micromobility vehicles, like scooters and three-wheelers. Since these vehicles tend to travel shorter distances at lower speeds than cars, the lower energy density of sodium-ion batteries might not be as big a deal.

There’s a great BBC story from last week that profiled efforts to put sodium-ion batteries in electric scooters. It focused on one Chinese company called Yadea, which is one of the largest makers of electric two- and three-wheelers in the world. Yadea has brought a handful of sodium-powered models to the market so far, selling about 1,000 of the scooters in the first three months of 2025, according to the company’s statement to the BBC. It’s early days, but it’s interesting to see this market emerging.

Sodium-ion batteries are also seeing significant progress in stationary energy storage installations, including some on the grid. (Again, if you’re not worried about carting the battery around and fitting it into the limited package of a vehicle, energy density isn’t so important.)

The Baochi Energy Storage Station that just opened in Yunnan province, China, is a hybrid system that uses both lithium-ion and sodium-ion batteries and has a capacity of 400 megawatt-hours. And Natron Energy in the US is among those targeting other customers for stationary storage, specifically going after data centers.

While smaller vehicles and stationary installations appear to be the early wins for sodium, some companies aren’t giving up on using the alternative for EVs as well. The Chinese battery giant CATL announced earlier this year that it plans to produce sodium-ion batteries for heavy-duty trucks under the brand name Naxtra Battery.

Ultimately, lithium is the juggernaut of the battery industry, and going head to head is going to be tough for any alternative chemistry. But sticking with niches that make sense could help sodium-ion make progress at a time when I’d argue we need every successful battery type we can get. 

This article is from The Spark, MIT Technology Review’s weekly climate newsletter. To receive it in your inbox every Wednesday, sign up here.

Over $1 billion in federal funding got slashed for this polluting industry

The clean cement industry might be facing the end of the road, before it ever really got rolling. 

On Friday, the US Department of Energy announced that it was canceling $3.7 billion in funding for 24 projects related to energy and industry. That included nearly $1.3 billion for cement-related projects.

Cement is a massive climate problem, accounting for roughly 7% of global greenhouse-gas emissions. What’s more, it’s a difficult industry to clean up, with huge traditional players and expensive equipment and infrastructure to replace. This funding was supposed to help address those difficulties, by supporting projects on the cusp of commercialization. Now companies will need to fill in the gap left by these cancellations, and it’s a big one. 

First up on the list for cuts is Sublime Systems, a company you’re probably familiar with if you’ve been reading this newsletter for a while. I did a deep dive last year, and the company was on our list of Climate Tech Companies to Watch in both 2023 and 2024.

The startup’s approach is to make cement using electricity. The conventional process requires high temperatures typically achieved by burning fossil fuels, so avoiding that could prevent a lot of emissions. 

In 2024, Sublime received an $87 million grant from the DOE to construct a commercial demonstration plant in Holyoke, Massachusetts. That grant would have covered roughly half the construction costs for the facility, which is scheduled to open in 2026 and produce up to 30,000 metric tons of cement each year. 

“We were certainly surprised and disappointed about the development,” says Joe Hicken, Sublime’s senior VP of business development and policy. Customers are excited by the company’s technology, Hicken adds, pointing to Sublime’s recently announced deal with Microsoft, which plans to buy up to 622,500 metric tons of cement from the company. 

Another big name, Brimstone, also saw its funding affected. That award totaled $189 million for a commercial demonstration plant, which was expected to produce over 100,000 metric tons of cement annually. 

In a statement, a Brimstone representative said the company believes the cancellation was a “misunderstanding.” The statement pointed out that the planned facility would make not only cement but also alumina, supporting US-based aluminum production. (Aluminum is classified as a critical mineral by the US Geological Survey, meaning it’s considered crucial to the US economy and national security.) 

An award to Heidelberg Materials for up to $500 million for a planned Indiana facility was also axed. The idea there was to integrate carbon capture and storage to clean up emissions from the plant, which would have made it the first cement plant in the US to demonstrate that technology. In a written statement, a representative said the decision can be appealed, and the company is considering that option.

And National Cement’s funding for the Lebec Net-Zero Project, another $500 million award, was canceled. That facility planned to make carbon-neutral cement through a combination of strategies: reducing the polluting ingredients needed, using alternative fuels like biomass, and capturing the plant’s remaining emissions. 

“We want to emphasize that this project will expand domestic manufacturing capacity for a critical industrial sector, while also integrating new technologies to keep American cement competitive,” said a company spokesperson in a written statement. 

There’s a sentiment here that’s echoed in all the responses I received: While these awards were designed to cut emissions, these companies argue that they can fit into the new administration’s priorities. They’re emphasizing phrases like “critical minerals,” “American jobs,” and “domestic supply chains.” 

“We’ve heard loud and clear from the Trump administration the desire to displace foreign imports of things that can be made here in America,” Sublime’s Hicken says. “At the end of the day, what we deliver is what the policymakers in DC are looking for.” 

But this administration is showing that it’s not supporting climate efforts—often even those that also advance its stated goals of energy abundance and American competitiveness. 

On Monday, my colleague James Temple published a new story about cuts to climate research, including tens of millions of dollars in grants from the National Science Foundation. Researchers at Harvard were particularly hard hit. 

Even as there’s interest in advancing the position of the US on the world’s stage, these cuts are making it hard for researchers and companies alike to do the crucial work of understanding our climate and developing and deploying new technologies. 

This article is from The Spark, MIT Technology Review’s weekly climate newsletter. To receive it in your inbox every Wednesday, sign up here.