Why EVs are gaining ground in Africa

EVs are getting cheaper and more common all over the world. But the technology still faces major challenges in some markets, including many countries in Africa.

Some regions across the continent still have limited grid and charging infrastructure, and those that do have widespread electricity access sometimes face reliability issues—a problem for EV owners, who require a stable electricity source to charge up and get around.

But there are some signs of progress. I just finished up a story about the economic case: A recent study in Nature Energy found that EVs from scooters to minibuses could be cheaper to own than gas-powered vehicles in Africa by 2040.

If there’s one thing to know about EVs in Africa, it’s that each of the 54 countries on the continent faces drastically different needs, challenges, and circumstances. There’s also a wide range of reasons to be optimistic about the prospects for EVs in the near future, including developing policies, a growing grid, and an expansion of local manufacturing.  

Even the world’s leading EV markets fall short of Ethiopia’s aggressively pro-EV policies. In 2024, the country became the first in the world to ban the import of non-electric private vehicles.

The case is largely an economic one: Gasoline is expensive there, and the country commissioned Africa’s largest hydropower dam in September 2025, providing a new source of cheap and abundant clean electricity. The nearly $5 billion project has a five-gigawatt capacity, doubling the grid’s peak power in the country.  

Much of Ethiopia’s vehicle market is for used cars, and some drivers are still opting for older gas-powered vehicles. But this nudge could help increase the market for EVs there.  

Other African countries are also pushing some drivers toward electrification. Rwanda banned new registrations for commercial gas-powered motorbikes in the capital city of Kigali last year, encouraging EVs as an alternative. These motorbike taxis can make up over half the vehicles on the city’s streets, so the move is a major turning point for transportation there. 

Smaller two- and three-wheelers are a bright spot for EVs globally: In 2025, EVs made up about 45% of new sales for such vehicles. (For cars and trucks, the share was about 25%.)

And Africa’s local market is starting to really take off. There’s already some local assembly of electric two-wheelers in countries including Morocco, Kenya, and Rwanda, says Nelson Nsitem, lead Africa energy transition analyst at BloombergNEF, an energy consultancy. 

Spiro, a Dubai-based electric motorbike company, recently raised $100 million in funding to expand operations in Africa. The company currently assembles its bikes in Uganda, Kenya, Nigeria, and Rwanda, and as of October it has over 60,000 bikes deployed and 1,500 battery swap stations operating.

Assembly and manufacturing for larger EVs and batteries is also set to expand. Gotion High-Tech, a Chinese battery company, is currently building Africa’s first battery gigafactory. It’s a $5.6 billion project that could produce 20 gigawatt-hours of batteries annually, starting in 2026. (That’s enough for hundreds of thousands of EVs each year.)

Chinese EV companies are looking to growing markets like Southeast Asia and Africa as they attempt to expand beyond an oversaturated domestic scene. BYD, the world’s largest EV company, is aggressively expanding across South Africa and plans to have as many as 70 dealerships in the country by the end of this year. That will mean more options for people in Africa looking to buy electric. 

“You have very high-quality, very affordable vehicles coming onto the market that are benefiting from the economies of scale in China. These countries stand to benefit from that,” says Kelly Carlin, a manager in the program on carbon-free transportation at the Rocky Mountain Institute, an energy think tank. “It’s a game changer,” he adds.

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Three questions about next-generation nuclear power, answered

Nuclear power continues to be one of the hottest topics in energy today, and in our recent online Roundtables discussion about next-generation nuclear power, hyperscale AI data centers, and the grid, we got dozens of great audience questions.

These ran the gamut, and while we answered quite a few (and I’m keeping some in mind for future reporting), there were a bunch we couldn’t get to, at least not in the depth I would have liked.

So let’s answer a few of your questions about advanced nuclear power. I’ve combined similar ones and edited them for clarity.

How are the fuel needs for next-generation nuclear reactors different, and how are companies addressing the supply chain?

Many next-generation reactors don’t use the low-enriched uranium used in conventional reactors.

It’s worth looking at high-assay low-enriched uranium, or HALEU, specifically. This fuel is enriched to higher concentrations of fissile uranium than conventional nuclear fuel, with a proportion of the isotope U-235 that falls between 5% and 20%. (In conventional fuel, it’s below 5%.)

HALEU can be produced with the same technology as low-enriched uranium, but the geopolitics are complicated. Today, Russia basically has a monopoly on HALEU production. In 2024, the US banned the import of Russian nuclear fuel through 2040 in an effort to reduce dependence on the country. Europe hasn’t taken the same measures, but it is working to move away from Russian energy as well.

That leaves companies in the US and Europe with the major challenge of securing the fuel they need when their regular Russian supply has been cut off or restricted.

The US Department of Energy has a stockpile of HALEU, which the government is doling out to companies to help power demonstration reactions. In the longer term, though, there’s still a major need to set up independent HALEU supply chains to support next-generation reactors.

How is safety being addressed, and what’s happening with nuclear safety regulation in the US?

There are some ways that next-generation nuclear power plants could be safer than conventional reactors. Some use alternative coolants that would prevent the need to run at the high pressure required in conventional water-cooled reactors. Many incorporate passive safety shutoffs, so if there are power supply issues, the reactors shut down harmlessly, avoiding risk of meltdown. (These can be incorporated in newer conventional reactors, too.)

But some experts have raised concerns that in the US, the current administration isn’t taking nuclear safety seriously enough.

A recent NPR investigation found that the Trump administration had secretly rewritten nuclear rules, stripping environmental protections and loosening safety and security measures. The government shared the new rules with companies that are part of a program building experimental nuclear reactors, but not with the public.

I’m reminded of a talk during our EmTech MIT event in November, where Koroush Shirvan, an MIT professor of nuclear engineering, spoke on this issue. “I’ve seen some disturbing trends in recent times, where words like ‘rubber-stamping nuclear projects’ are being said,” Shirvan said during that event.  

During the talk, Shirvan shared statistics showing that nuclear power has a very low rate of injury and death. But that’s not inherent to the technology, and there’s a reason injuries and deaths have been low for nuclear power, he added: “It’s because of stringent regulatory oversight.”  

Are next-generation reactors going to be financially competitive?

Building a nuclear power plant is not cheap. Let’s consider the up-front investment needed to build a power plant.  

Plant Vogtle in Georgia hosts the most recent additions to the US nuclear fleet—Units 3 and 4 came online in 2023 and 2024. Together, they had a capital cost of $15,000 per kilowatt, adjusted for inflation, according to a recent report from the US Department of Energy. (This wonky unit I’m using divides the total cost to build the reactors by their expected power output, so we can compare reactors of different sizes.)

That number’s quite high, partly because those were the first of their kind built in the US, and because there were some inefficiencies in the planning. It’s worth noting that China builds reactors for much less, somewhere between $2,000/kW and $3,000/kW, depending on the estimate.

The up-front capital cost for first-of-a-kind advanced nuclear plants will likely run between $6,000 and $10,000 per kilowatt, according to that DOE report. That could come down by up to 40% after the technologies are scaled up and mass-produced.

So new reactors will (hopefully) be cheaper than the ultra-over-budget and behind-schedule Vogtle project, but they aren’t necessarily significantly cheaper than efficiently built conventional plants, if you normalize by their size.

It’ll certainly be cheaper to build new natural-gas plants (setting aside the likely equipment shortages we’re likely going to see for years.) Today’s most efficient natural-gas plants cost just $1,600/kW on the high end, according to data from Lazard.

An important caveat: Capital cost isn’t everything—running a nuclear plant is relatively inexpensive, which is why there’s so much interest in extending the lifetime of existing plants or reopening shuttered ones.

Ultimately, by many metrics, nuclear plants of any type are going to be more expensive than other sources, like wind and solar power. But they provide something many other power sources don’t: a reliable, stable source of electricity that can run for 60 years or more.

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How the grid can ride out winter storms

The eastern half of the US saw a monster snowstorm over the weekend. The good news is the grid has largely been able to keep up with the freezing temperatures and increased demand. But there were some signs of strain, particularly for fossil-fuel plants.

One analysis found that PJM, the nation’s largest grid operator, saw significant unplanned outages in plants that run on natural gas and coal. Historically, these facilities can struggle in extreme winter weather.

Much of the country continues to face record-low temperatures, and the possibility is looming for even more snow this weekend. What lessons can we take from this storm, and how might we shore up the grid to cope with extreme weather?

Living in New Jersey, I have the honor of being one of the roughly 67 million Americans covered by the PJM Interconnection.

So I was in the thick of things this weekend, when PJM saw unplanned outages of over 20 gigawatts on Sunday during the height of the storm. (That’s about 16% of the grid’s demand that afternoon.) Other plants were able to make up the difference, and thankfully, the power didn’t go out in my area. But that’s a lot of capacity offline.

Typically, the grid operator doesn’t announce details about why an outage occurs until later. But analysts at Energy Innovation, a policy and research firm specializing in energy and climate, went digging. By examining publicly available grid mix data (a breakdown of what types of power plants are supplying the grid), the team came to a big conclusion: Fossil fuels failed during the storm.

The analysts found that gas-fired power plants were producing about 10 gigawatts less power on Sunday than the peak demand on Saturday, even while electricity prices were high. Coal- and oil-burning plants were down too. Because these plants weren’t operating, even when high prices would make it quite lucrative, they were likely a significant part of the problem, says Michelle Solomon, a manager in the electricity program at Energy Innovation.

PJM plans to share more details about the outages at an upcoming committee meeting once the cold snap passes, Dan Lockwood, a PJM spokesperson, told me via email.

Fossil-fuel plants can see reliability challenges during winter: When temperatures drop, pressures in natural-gas lines fall too, which can lead to issues for fuel supply. Freezing temperatures can throw compression stations and other mechanical equipment offline and even freeze piles of coal.

One of the starkest examples came in 2021, when Texas faced freezing temperatures that took many power plants offline and threw the grid into chaos. Many homes lost power for days, and at least 246 people died during that storm.

Texas fared much better this time around. After 2021, the state shored up its grid, adding winter weatherization for power plants and transmission systems. Texas has also seen a huge flood of batteries come online, which has greatly helped the grid during winter demand peaks, especially in the early mornings. Texas was also simply lucky that this storm was less severe there, as one expert told Inside Climate News this week.

Here on the East Coast, we’re not out of the woods yet. The snow has stopped falling, but grids are still facing high electricity demand because of freezing temperatures. (I’ve certainly been living under my heated blanket these last few days.)

PJM could see a peak power demand of 130 gigawatts for seven straight days, a winter streak that the local grid has never experienced, according to an update to the utility’s site on Tuesday morning.

The US Department of Energy issued emergency orders to several grid operators, including PJM, that allow power plants to run while basically ignoring emissions regulations. The department also issued orders allowing several grids to tell data centers and other facilities to begin using backup generators. (This is good news for reliability but bad news for clean air and the climate, since these power sources are often incredibly emissions-intensive.)

We here on the East Coast could learn a thing or two from Texas so we don’t need to resort to these polluting emergency measures to keep the lights on. More energy storage could be a major help in future winter storms, lending flexibility to the grid to help ride out the worst times, Solomon says. Getting offshore wind online could also help, since those facilities typically produce reliable power in the winter. 

No one energy source will solve the massive challenge of building and maintaining a resilient grid. But as we face the continued threat of extreme storms, renewables might actually help us weather them. 

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Why 2026 is a hot year for lithium

In 2026, I’m going to be closely watching the price of lithium.

If you’re not in the habit of obsessively tracking commodity markets, I certainly don’t blame you. (Though the news lately definitely makes the case that minerals can have major implications for global politics and the economy.)

But lithium is worthy of a close look right now.

The metal is crucial for lithium-ion batteries used in phones and laptops, electric vehicles, and large-scale energy storage arrays on the grid. Prices have been on quite the roller coaster over the last few years, and they’re ticking up again after a low period. What happens next could have big implications for mining and battery technology.

Before we look ahead, let’s take a quick trip down memory lane. In 2020, global EV sales started to really take off, driving up demand for the lithium used in their batteries. Because of that growing demand and a limited supply, prices shot up dramatically, with lithium carbonate going from under $10 per kilogram to a high of roughly $70 per kilogram in just two years.

And the tech world took notice. During those high points, there was a ton of interest in developing alternative batteries that didn’t rely on lithium. I was writing about sodium-based batteries, iron-air batteries, and even experimental ones that were made with plastic.

Researchers and startups were also hunting for alternative ways to get lithium, including battery recycling and processing methods like direct lithium extraction (more on this in a moment).

But soon, prices crashed back down to earth. We saw lower-than-expected demand for EVs in the US, and developers ramped up mining and processing to meet demand. Through late 2024 and 2025, lithium carbonate was back around $10 a kilogram again. Avoiding lithium or finding new ways to get it suddenly looked a lot less crucial.

That brings us to today: lithium prices are ticking up again. So far, it’s nowhere close to the dramatic rise we saw a few years ago, but analysts are watching closely. Strong EV growth in China is playing a major role—EVs still make up about 75% of battery demand today. But growth in stationary storage, batteries for the grid, is also contributing to rising demand for lithium in both China and the US.

Higher prices could create new opportunities. The possibilities include alternative battery chemistries, specifically sodium-ion batteries, says Evelina Stoikou, head of battery technologies and supply chains at BloombergNEF. (I’ll note here that we recently named sodium-ion batteries to our 2026 list of 10 Breakthrough Technologies.)

It’s not just batteries, though. Another industry that could see big changes from a lithium price swing: extraction.

Today, most lithium is mined from rocks, largely in Australia, before being shipped to China for processing. There’s a growing effort to process the mineral in other places, though, as countries try to create their own lithium supply chains. Tesla recently confirmed that it’s started production at its lithium refinery in Texas, which broke ground in 2023. We could see more investment in processing plants outside China if prices continue to climb.

This could also be a key year for direct lithium extraction, as Katie Brigham wrote in a recent story for Heatmap. That technology uses chemical or electrochemical processes to extract lithium from brine (salty water that’s usually sourced from salt lakes or underground reservoirs), quickly and cheaply. Companies including Lilac Solutions, Standard Lithium, and Rio Tinto are all making plans or starting construction on commercial facilities this year in the US and Argentina. 

If there’s anything I’ve learned about following batteries and minerals over the past few years, it’s that predicting the future is impossible. But if you’re looking for tea leaves to read, lithium prices deserve a look. 

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Three climate technologies breaking through in 2026

Happy New Year! I know it’s a bit late to say, but it never quite feels like the year has started until the new edition of our 10 Breakthrough Technologies list comes out. 

For 25 years, MIT Technology Review has put together this package, which highlights the technologies that we think are going to matter in the future. This year’s version has some stars, including gene resurrection (remember all the dire wolf hype last year?) and commercial space stations. 

And of course, the world of climate and energy is represented with sodium-ion batteries, next-generation nuclear, and hyperscale AI data centers. Let’s take a look at what ended up on the list, and what it says about this moment for climate tech. 

Sodium-ion batteries

I’ve been covering sodium-ion batteries for years, but this moment feels like a breakout one for the technology. 

Today, lithium-ion cells power everything from EVs, phones, and computers to huge stationary storage arrays that help support the grid. But researchers and battery companies have been racing to develop an alternative, driven by the relative scarcity of lithium and the metal’s volatile price in recent years. 

Sodium-ion batteries could be that alternative. Sodium is much more abundant than lithium, and it could unlock cheaper batteries that hold a lower fire risk.  

There are limitations here: Sodium-ion batteries won’t be able to pack as much energy into cells as their lithium counterparts. But it might not matter, especially for grid storage and smaller EVs. 

In recent years, we’ve seen a ton of interest in sodium-based batteries, particularly from major companies in China. Now the new technology is starting to make its way into the world—CATL says it started manufacturing these batteries at scale in 2025. 

Next-generation nuclear

Nuclear reactors are an important part of grids around the world today—massive workhorse reactors generate reliable, consistent electricity. But the countries with the oldest and most built-out fleets have struggled to add to them in recent years, since reactors are massive and cost billions. Recent high-profile projects have gone way over budget and faced serious delays. 

Next-generation reactor designs could help the industry break out of the old blueprint and get more nuclear power online more quickly, and they’re starting to get closer to becoming reality. 

There’s a huge variety of proposals when it comes to what’s next for nuclear. Some companies are building smaller reactors, which they say could make it easier to finance new projects, and get them done on time. 

Other companies are focusing on tweaking key technical bits of reactors, using alternative fuels or coolants that help ferry heat out of the reactor core. These changes could help reactors generate electricity more efficiently and safely. 

Kairos Power was the first US company to receive approval to begin construction on a next-generation reactor to produce electricity. China is emerging as a major center of nuclear development, with the country’s national nuclear company reportedly working on several next-gen reactors. 

Hyperscale data centers

This one isn’t quite what I would call a climate technology, but I spent most of last year reporting on the climate and environmental impacts of AI, and the AI boom is deeply intertwined with climate and energy. 

Data centers aren’t new, but we’re seeing a wave of larger centers being proposed and built to support the rise of AI. Some of these facilities require a gigawatt or more of power—that’s like the output of an entire conventional nuclear power plant, just for one data center. 

(This feels like a good time to mention that our Breakthrough Technologies list doesn’t just highlight tech that we think will have a straightforwardly positive influence on the world. I think back to our 2023 list, which included mass-market military drones.)

There’s no denying that new, supersize data centers are an important force driving electricity demand, sparking major public pushback, and emerging as a key bit of our new global infrastructure. 

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What new legal challenges mean for the future of US offshore wind

For offshore wind power in the US, the new year is bringing new legal battles.

On December 22, the Trump administration announced it would pause the leases of five wind farms currently under construction off the US East Coast. Developers were ordered to stop work immediately.

The cited reason? National security, specifically concerns that turbines can cause radar interference. But that’s a known issue, and developers have worked with the government to deal with it for years.

Companies have been quick to file lawsuits, and the court battles could begin as soon as this week. Here’s what the latest kerfuffle might mean for the struggling offshore wind industry in the US.

This pause affects $25 billion in investment in five wind farms: Vineyard Wind 1 off Massachusetts, Revolution Wind off Rhode Island, Sunrise Wind and Empire Wind off New York, and Coastal Virginia Offshore Wind off Virginia. Together, those projects had been expected to create 10,000 jobs and power more than 2.5 million homes and businesses.

In a statement announcing the move, the Department of the Interior said that “recently completed classified reports” revealed national security risks, and that the pause would give the government time to work through concerns with developers. The statement specifically says that turbines can create radar interference (more on the technical details here in a moment).

Three of the companies involved have already filed lawsuits, and they’re seeking preliminary injunctions that would allow construction to continue. Orsted and Equinor (the developers for Revolution Wind and Empire Wind, respectively) told the New York Times that their projects went through lengthy federal reviews, which did address concerns about national security.

This is just the latest salvo from the Trump administration against offshore wind. On Trump’s first day in office, he signed an executive order stopping all new lease approvals for offshore wind farms. (That order was struck down by a judge in December.)

The administration previously ordered Revolution Wind to stop work last year, also citing national security concerns. A federal judge lifted the stop-work order weeks later, after the developer showed that the financial stakes were high, and that government agencies had previously found no national security issues with the project.

There are real challenges that wind farms introduce for radar systems, which are used in everything from air traffic control to weather forecasting to national defense operations. A wind turbine’s spinning can create complex signatures on radar, resulting in so-called clutter.

Previous government reports, including one 2024 report from the Department of Energy and a 2025 report from the Government Accountability Office (an independent government watchdog), have pointed out this issue in the past.

“To date, no mitigation technology has been able to fully restore the technical performance of impacted radars,” as the DOE report puts it. However, there are techniques that can help, including software that acts to remove the signatures of wind turbines. (Think of this as similar to how noise-canceling headphones work, but more complicated, as one expert told TechCrunch.)

But the most widespread and helpful tactic, according to the DOE report, is collaboration between developers and the government. By working together to site and design wind farms strategically, the groups can ensure that the projects don’t interfere with government or military operations. The 2025 GAO report found that government officials, researchers, and offshore wind companies were collaborating effectively, and any concerns could be raised and addressed in the permitting process.

This and other challenges threaten an industry that could be a major boon for the grid. On the East Coast where these projects are located, and in New England specifically, winter can bring tight supplies of fossil fuels and spiking prices because of high demand. It just so happens that offshore winds blow strongest in the winter, so new projects, including the five wrapped up in this fight, could be a major help during the grid’s greatest time of need.

One 2025 study found that if 3.5 gigawatts’ worth of offshore wind had been operational during the 2024-2025 winter, it would have lowered energy prices by 11%. (That’s the combined capacity of Revolution Wind and Vineyard Wind, two of the paused projects, plus two future projects in the pipeline.) Ratepayers would have saved $400 million.

Before Donald Trump was elected, the energy consultancy BloombergNEF projected that the US would build 39 gigawatts of offshore wind by 2035. Today, that expectation has dropped to just 6 gigawatts. These legal battles could push it lower still.

What’s hardest to wrap my head around is that some of the projects being challenged are nearly finished. The developers of Revolution Wind have installed all the foundations and 58 of 65 turbines, and they say the project is over 87% complete. Empire Wind is over 60% done and is slated to deliver electricity to the grid next year.

To hit the pause button so close to the finish line is chilling, not just for current projects but for future offshore wind efforts in the US. Even if these legal battles clear up and more developers can technically enter the queue, why would they want to? Billions of dollars are at stake, and if there’s one word to describe the current state of the offshore wind industry in the US, it’s “unpredictable.”

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Can AI really help us discover new materials?

Judging from headlines and social media posts in recent years, one might reasonably assume that AI is going to fix the power grid, cure the world’s diseases, and finish my holiday shopping for me. But maybe there’s just a whole lot of hype floating around out there.

This week, we published a new package called Hype Correction. The collection of stories takes a look at how the world is starting to reckon with the reality of what AI can do, and what’s just fluff.

One of my favorite stories in that package comes from my colleague David Rotman, who took a hard look at AI for materials research. AI could transform the process of discovering new materials—innovation that could be especially useful in the world of climate tech, which needs new batteries, semiconductors, magnets, and more. 

But the field still needs to prove it can make materials that are actually novel and useful. Can AI really supercharge materials research? What could that look like?

For researchers hoping to find new ways to power the world (or cure disease or achieve any number of other big, important goals), a new material could change everything.

The problem is, inventing materials is difficult and slow. Just look at plastic—the first totally synthetic plastic was invented in 1907, but it took until roughly the 1950s for companies to produce the wide range we’re familiar with today. (And of course, though it is incredibly useful, plastic also causes no shortage of complications for society.)

In recent decades, materials science has fallen a bit flat—David has been covering this field for nearly 40 years, and as he puts it, there have been just a few major commercial breakthroughs in that time. (Lithium-ion batteries are one.)

Could AI change everything? The prospect is a tantalizing one, and companies are racing to test it out.

Lila Sciences, based in Cambridge, Massachusetts, is working on using AI models to uncover new materials. The company can not only train an AI model on all the latest scientific literature, but also plug it into an automated lab, so it can learn from experimental data. The goal is to speed up the iterative process of inventing and testing new materials and look at research in ways that humans might miss.

At an MIT Technology Review event earlier this year, I got to listen to David interview Rafael Gómez-Bombarelli, one of Lila’s cofounders. As he described what the company is working on, Gómez-Bombarelli acknowledged that AI materials discovery hasn’t yet seen a big breakthrough moment. Yet.

Gómez-Bombarelli described how models Lila has trained are providing insights that are “as deep [as] or deeper than our domain scientists would have.” In the future, AI could “think” in ways that depart from how human scientists approach a problem, he added: “There will be a need to translate scientific reasoning by AI to the way we think about the world.”

It’s exciting to see this sort of optimism in materials research, but there’s still a long and winding road before we can satisfyingly say that AI has transformed the field. One major difficulty is that it’s one thing to take suggestions from a model about new experimental methods or new potential structures. It’s quite another to actually make a material and show that it’s novel and useful.

You might remember that a couple of years ago, Google’s DeepMind announced it had used AI to predict the structures of “millions of new materials” and had made hundreds of them in the lab.

But as David notes in his story, after that announcement, some materials scientists pointed out that some of the supposedly novel materials were basically slightly different versions of known ones. Others couldn’t even physically exist in normal conditions (the simulations were done at ultra-low temperatures, where atoms don’t move around much).

It’s possible that AI could give materials discovery a much-needed jolt and usher in a new age that brings superconductors and batteries and magnets we’ve never seen before. But for now, I’m calling hype. 

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Why the grid relies on nuclear reactors in the winter

As many of us are ramping up with shopping, baking, and planning for the holiday season, nuclear power plants are also getting ready for one of their busiest seasons of the year.

Here in the US, nuclear reactors follow predictable seasonal trends. Summer and winter tend to see the highest electricity demand, so plant operators schedule maintenance and refueling for other parts of the year.

This scheduled regularity might seem mundane, but it’s quite the feat that operational reactors are as reliable and predictable as they are. It leaves some big shoes to fill for next-generation technology hoping to join the fleet in the next few years.

Generally, nuclear reactors operate at constant levels, as close to full capacity as possible. In 2024, for commercial reactors worldwide, the average capacity factor—the ratio of actual energy output to the theoretical maxiumum—was 83%. North America rang in at an average of about 90%.

(I’ll note here that it’s not always fair to just look at this number to compare different kinds of power plants—natural-gas plants can have lower capacity factors, but it’s mostly because they’re more likely to be intentionally turned on and off to help meet uneven demand.)

Those high capacity factors also undersell the fleet’s true reliability—a lot of the downtime is scheduled. Reactors need to refuel every 18 to 24 months, and operators tend to schedule those outages for the spring and fall, when electricity demand isn’t as high as when we’re all running our air conditioners or heaters at full tilt.

Take a look at this chart of nuclear outages from the US Energy Information Administration. There are some days, especially at the height of summer, when outages are low, and nearly all commercial reactors in the US are operating at nearly full capacity. On July 28 of this year, the fleet was operating at 99.6%. Compare that with  the 77.6% of capacity on October 18, as reactors were taken offline for refueling and maintenance. Now we’re heading into another busy season, when reactors are coming back online and shutdowns are entering another low point.

That’s not to say all outages are planned. At the Sequoyah nuclear power plant in Tennessee, a generator failure in July 2024 took one of two reactors offline, an outage that lasted nearly a year. (The utility also did some maintenance during that time to extend the life of the plant.) Then, just days after that reactor started back up, the entire plant had to shut down because of low water levels.

And who can forget the incident earlier this year when jellyfish wreaked havoc on not one but two nuclear power plants in France? In the second instance, the squishy creatures got into the filters of equipment that sucks water out of the English Channel for cooling at the Paluel nuclear plant. They forced the plant to cut output by nearly half, though it was restored within days.

Barring jellyfish disasters and occasional maintenance, the global nuclear fleet operates quite reliably. That wasn’t always the case, though. In the 1970s, reactors operated at an average capacity factor of just 60%. They were shut down nearly as often as they were running.

The fleet of reactors today has benefited from decades of experience. Now we’re seeing a growing pool of companies aiming to bring new technologies to the nuclear industry.

Next-generation reactors that use new materials for fuel or cooling will be able to borrow some lessons from the existing fleet, but they’ll also face novel challenges.

That could mean early demonstration reactors aren’t as reliable as the current commercial fleet at first. “First-of-a-kind nuclear, just like with any other first-of-a-kind technologies, is very challenging,” says Koroush Shirvan, a professor of nuclear science and engineering at MIT.

That means it will probably take time for molten-salt reactors or small modular reactors, or any of the other designs out there to overcome technical hurdles and settle into their own rhythm. It’s taken decades to get to a place where we take it for granted that the nuclear fleet can follow a neat seasonal curve based on electricity demand. 

There will always be hurricanes and electrical failures and jellyfish invasions that cause some unexpected problems and force nuclear plants (or any power plants, for that matter) to shut down. But overall, the fleet today operates at an extremely high level of consistency. One of the major challenges ahead for next-generation technologies will be proving that they can do the same.

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