Nuclear power plants have been significant U.S. energy producers since the late 1960s. Today, they supply about 20% of our electricity needs and an even bigger proportion of carbon-free kilowatt-hours. But the design goals for these facilities haven’t shifted much in the last 60 years.

That’s been changing lately as developers have been studying new ways to use the technology for plants that are much smaller or, potentially, much larger than what we’ve been familiar with for decades. This includes growing investments in the power industry’s Holy Grail, nuclear fusion, a promising pillar supporting the electrification of everything.

Small modular reactors

At the smaller end of the spectrum, several companies are moving forward with plans for small modular reactors (SMRs) that they claim will be safer and quicker to build. In addition to utilities, these startups are eyeing manufacturers and tech operators as potential clients. 

For example, Portland, Ore.-based NuScale Power Corp., the only SMR designer to receive design approval so far from the U.S. Nuclear Regulatory Commission (NRC), now has a partnership arrangement with energy infrastructure firms Standard Power, Coshocton, Ohio, and ENTRA1 Energy, Houston, to develop two SMR plants that will directly support advanced data centers in Ohio and Pennsylvania. NuScale’s designs—including 24 modules, each with a capacity of a mere 77 megawatts (MW)—are intended to be factory-built and delivered to their job sites, with no in-field construction. The plants are expected to be up and running by 2029.

The U.S. Army has big plans for even smaller nuclear generators. In June, it announced it was seeking proposals for microreactors producing between 3 MW and 10 MW to support applications that could include typical army bases or forward units in the field that lack direct grid access. Congress has mandated the Army support its critical missions with 99.9% reliable energy by 2030. One advantage the service branch has in meeting this ambitious deadline is its ability to sidestep the NRC’s lengthy approval process, as U.S. Department of Defense rules enable its military departments to regulate on-base nuclear facilities.

Nuclear fusion

But the biggest news lately has focused on much larger opportunities—specifically, nuclear fusion. This technology has long offered promise for inexpensive, waste-free electricity generation using the same science that powers the sun. It’s also been seen as 20 years away from reality for the last 40 years. But recent scientific breakthroughs have given prognosticators hope that such an optimistic forecast is, at least, achievable.

In December 2022, researchers at the Lawrence Livermore National Laboratory (LLNL) were the first to produce more energy from fusion than the laser energy used to drive the event. The breakthrough—called a break-even point—provided a proof of concept that it’s possible to create the conditions for fusion to produce excess energy. The experiment also achieved self-­heating, which means the reaction was able to power itself, a necessity for a future fusion generating plant. The feat was repeated in July 2023.

Then this past February, researchers at England’s Oxford University were able to produce their own fusion reaction for five seconds, sustaining a record output of 69 megajoules—enough to power about 12,000 households for the same amount of time.

These accomplishments, though important, don’t mean fusion technology is yet economically feasible. While the reactions might have generated more energy than was used by the lasers used to ignite them, that energy equation flips significantly when including the energy required to power the lasers that make a fusion reaction possible. So, while the initial LLNL experiment created about 1.5 times as much energy as the lasers supplied, fusion scientists have suggested that reactions need to produce 100 times as much energy for viable use in commercialized power generation.

These technical challenges aren’t slowing down bullish regulators and investors. In spring of last year, the NRC voted to establish an approval process for future fusion generators that would be faster than that used for fission efforts, because the new technology poses much less radioactive hazard, and its primary waste product is helium. President Biden signed the Accelerating Deployment of Versatile, Advanced Nuclear for Clean Energy (ADVANCE) Act into law in July 2024.

As with SMRs, large power users are interested in tapping fission’s potential to decarbonize their operations. Microsoft, Redmond, Wash., was first in line, signing a deal with Everett, Wash.-based startup Helion to buy 50 MW of electricity from a plant the company expects will be operational by 2028. 

Helion also has an agreement with Nucor, Charlotte, N.C., North America’s largest steel producer, to develop a 500-MW plant proposed to be online by 2030. Nucor’s operations already are heavily electrified—the company uses electric-arc furnaces, rather than the more standard blast furnaces. Ensuring the electricity is sourced from an emissions-free producer would be a big step in taking fossil fuels out of steel manufacturing.

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