Powering the AI data center boom dominated the conversation in the global energy sector in 2025. Governments are racing to develop the most advanced AI models, and data center developers are building as fast as they can. But no one is going to get very far without finding ways to generate and move more electricity to these power guzzlers.

Spectrum’s most popular energy stories in 2025 centered around that theme. Readers were particularly interested in stories about next-generation nuclear power, such as small modular reactors and salt-cooled reactors, and how those technologies might support data centers. Readers also turned to Spectrum to learn about the strain all of this is putting on electricity grids, and new technologies to solve those problems.

Despite the weightiness of the energy sector’s challenges, we found some fun, off-beat stories to tell too. One American company is building the world’s largest airplane—it’s bigger than a football field—and it will have one job: to transport wind turbine blades.

I don’t know what 2026 will bring, but as Spectrum’s energy editor, I’ll do my best to provide you stories that are true, useful, and engaging. Cheers to a new year in energy!

1. U.S. Pushes for Small Modular Reactors

Three dimensional rendering of a small nuclear reactor. GE Vernova

The world suddenly needs more power, but one solution being tested is to downsize energy generation and distribute it more widely. One example of that is small modular reactors (SMRs). These nuclear fission reactors are less than a third of the size and power output of conventional reactors. And as the April deadline approached for applying for the US $900 million the United States was offering for SMR development, readers came to Spectrum in droves to learn about the program in a news article authored by contributor Shannon Cuthrell.

But the SMR money paled in comparison to the $80 billion that the United States is spending on a fleet of large-scale nuclear reactors designed by Westinghouse. Will this next group of reactors suffer from the same delays and cost overruns as the ones that put Westinghouse into bankruptcy just a few years ago? Spectrum brought readers an expert analysis on the subject by Wood MacKenzie’s Ed Crooks.

2. Why China is Building a Thorium Molten-Salt Reactor

Part of a periodic table with light coming out from the "Thorium" element. Edmon de Haro

The United States may have the most SMRs in development, but China has the one that’s furthest along. The Linglong One, on the island of Hainan, is expected to begin operations in the first half of 2026. And that’s just one component in a smorgasbord of nuclear reactor experimentation in China. One of the country’s most interesting projects is a thorium-powered, molten-salt reactor, which it began building in 2025 in the Gobi desert. Prior to this project, the last operating molten-salt reactor was at Oak Ridge National Laboratory, which shut down in 1969.

The attraction of thorium as a fuel is that it reduces dependence on uranium. Very little information is available on the progress of China’s thorium reactor, but with help from our Taiwan-based freelancer Yu-Tzu Chiu, we know it’s small—only 10 megawatts—and is scheduled to be operational by 2030. Check back with Spectrum for updates on this reactor and the Linglong One.

3. If We Want Bigger Wind Turbines, We’re Gonna Need Bigger Airplanes

A rendering of the WindRunner aircraft in flight over mountainous desert Radia

While nuclear reactors need to get smaller, wind turbines need to get bigger, say some renewable energy advocates. And the biggest obstacle to bigger wind—besides the present political backlash—is transportation. Roads, bridges, and train tracks dictate the size of on-shore wind turbine blades, and usually can’t accommodate anything over 70 meters long. That’s why Radia, an aviation startup in Boulder, Colo., is building the world’s largest airplane. It will stretch 108 meters in length, be shaped to hold a 105-meter blade, and can land on a makeshift dirt runway. Spectrum contributor Andrew Moseman traveled to Radia’s headquarters to check out the aircraft’s design and fly the behemoth on the company’s simulator. (Spoiler: He landed it.)

4. This Low-Cost Stopgap Tech Can Fix the Grid

Three rows of machines outdoors surrounded by a fence National Grid Electricity Transmission/Smart Wires

None of this new energy generation will matter if we can’t move it across the grid to customers who need it. But many key transmission corridors are maxed. Blackouts are growing longer and more common. Building new transmission lines takes years and often gets thwarted by NIMBY pushback. Queues for connecting to the grid, whether you’re providing power or requesting it, can be comically long.

To bridge the gap, grid operators globally are turning to innovative grid tech. Collectively called grid-enhancing technologies (GETs), some of the boldest examples can be found in the United Kingdom. For example, the U.K.’s National Grid has been implementing electronic power-flow controllers, called SmartValves, that shift electricity from jammed circuits to those with spare capacity.

The U.K. and other countries have also been reconductoring old lines and installing dynamic line rating, which calculates how much current high-voltage lines can safely carry based on real-time weather conditions. And Scotland has been beefing up its grid-scale battery stations with advanced converters. These leap into action within milliseconds to release the extra power needed when energy supply elsewhere on the grid falters. Spectrum contributor Peter Fairley, who authored several of these stories, traveled to the U.K. to investigate grid congestion woes and tech solutions.

5. Cuba’s Power Grid Nears Total Failure

Car headlights illuminate a residential street at night during a power outage in Cuba. Yamil Lage/AFP/Getty Images

At the opposite end of the spectrum, one of the world’s most neglected grids can be found in Cuba. There, decades of poor fuel and maintenance have left the country’s energy infrastructure in crisis. Lately, Cuba’s entire grid has been collapsing every couple of months. Blackouts are so common that citizens are cooking multiple meals at once and working by flashlight, says Ricardo Torres, a Cuban economist who explained the situation for Spectrum readers in this popular expert-authored guest post.

The nearby Caribbean island of Puerto Rico has also been enduring more frequent blackouts, leading some to speculate that the grid in this American territory may go the same way as Cuba’s. The turmoil has prompted widespread development of solar-plus-storage systems across the island that are privately financed, reports Spectrum contributor Julia Tilton.

6. The Unlikely Revival of Nuclear Batteries

Yellow cylinder with nuclear symbol, plus-minus signs, casting shadow on blue background. Edmon de Haro

On the lighter side, we also explored the world of nuclear batteries. These devices store energy in the form of radioactive isotopes. They can last for decades, making them ideal for medical implants, remote infrastructure, robots, and sensors. But the allure of a small battery with a 50-year lifespan has given this sector several false starts. There was a stint in the 1970s where surgeons implanted nuclear-powered pacemakers in over 1,400 people only to lose track of them over time. Regulators balked when devices containing plutonium-238 started turning up in crematoriums and coffins.

Now the field is experiencing a resurgence in interest. Companies on multiple continents are claiming to be on the verge of commercialization of nuclear batteries. Whether they’ll find willing markets is unclear. In a feature for Spectrum, nuclear battery expert James Blanchard details the history of these devices and why there’s suddenly more activity in this field than he’s ever seen in his 40-year career.

7. Electric Vehicles Made These Engineers Expendable

Two men standing between a silver truck and a blue truck in front of a brick building. Brittany Greeson

Sometimes a story is so good that we just have to publish it, even if we find it somewhere else. That was the case with a chapter from the book Inevitable: Inside the Messy, Unstoppable Transition to Electric Vehicles (Harvard Business Review Press, 2025). The chapter tells the tale of one power-train engineer at Ford whose internal-combustion-engine expertise slowly became expendable as car companies pivoted to EVs. With permission, we published an adapted version of the chapter, which is chock-full of excellent reporting from author Mike Colias, a veteran automotive reporter. Don’t miss it! (Spoiler: The engineer, Lem Yeung, who left Ford after 30 years, ended up returning to the company a few years later to help clean up the mess caused by the loss of old-school talent. We caught up with Yeung after his return in this Q&A.)

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The Top 7 Energy Stories of 2025

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