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Commonwealth Fusion Systems (CFS), an offshoot of the Massachusetts Institute of Technology, announced plans on Tuesday to build the world’s first grid-scale commercial nuclear fusion power plant in Chesterfield County, Virginia.

The ARC (Affordable, Robust, Compact) fusion reactor will be located in the James River Industrial Park and aims to revolutionize clean energy production.

“This is a historic moment,” said Bob Mumgaard, CEO and co-founder of CFS, in a statement. “By the early 1930s, all eyes will be on Chesterfield County as the cradle of commercial fusion power.”

The plant is expected to generate 400 megawatts of electricity, enough to power around 150,000 homes or large industrial facilities.

What is nuclear fusion?

Nuclear fusion is the process of combining two light atomic nuclei to form a heavier one, releasing enormous amounts of energy. This process powers the Sun and other stars, existing in a state of matter known as plasma—a hot, charged gas distinct from solids, liquids, and gases.

Unlike nuclear fission, which splits heavy nuclei like uranium and is currently used in nuclear power plants, fusion offers several advantages.

It produces significantly more energy per unit of fuel—and, according to the International Atomic Energy Agency, four million times more per kilogram than burning coal—and prevents long-term radioactive waste.

Fusion fuel – isotopes of hydrogen such as deuterium and tritium – is abundant, with deuterium coming from seawater and tritium potentially being created using lithium.

Fusion is inherently safe because the reactions only take place under precise conditions. If these conditions are not met, the reaction stops, eliminating the risks of runaway scenarios such as those seen in fission-based disasters such as Chernobyl.

Despite its promise, fusion requires extremely high temperatures and pressure to overcome the natural resistance between atomic nuclei, a problem that has taken decades of research.

In 2022, scientists achieved a historic milestone by generating more energy from fusion than was needed to start the reaction—a feat more than 70 years in the making. However, significant obstacles still remain.

Brian Appelbe, a researcher at the Center for Inertial Fusion Studies at Imperial College London, who is not affiliated with the project, highlighted two main obstacles: keeping the fusion process stable and turning the resulting energy into practical use.

In stars, immense gravitational forces counteract this tendency and hold the plasma together. “What we’re trying to do on Earth is find ways to limit small amounts of this incredibly hot plasma,” Appelbe said.

Even when containment is achieved, the task of harnessing the energy remains daunting.

“In these reactors, the energy is released in the form of charged particles and high-energy neutrons. The charged particles stay in the hot plasma, and the neutrons are the things that come out,” Appelbe said.

Neutrons fly out at extremely high speeds, so engineers must find ways to convert their kinetic energy into heat that can be used to power steam turbines.

CFS has yet to build its SPARC (short for “smallest possible ARC”) demonstration reactor, which is slated to start operating in 2027.

Applebe believes SPARC will be a critical litmus test for CFS’s ambitious goal of delivering a commercial fusion power plant by the early 2030s.

How is nuclear power produced?

Nuclear energy uses Einstein’s famous equation E = mc², where energy is derived from the “mass defect” – the difference in mass before and after nuclear reactions.

In both fusion and fission, this small mass difference translates into a huge release of energy due to the speed of light (“c” in the equation) squared, which is a massive multiplier.

Fusion reactors like the ARC will generate electricity by using the energy released during the reactions to heat water into steam, which then drives turbines – much like traditional power plants. A key challenge, however, lies in the efficient use of the fast-moving neutrons produced by the reaction to convert their energy into usable heat.

Do nuclear power plants pollute?

Nuclear power plants, whether based on fission or fusion, do not emit greenhouse gases such as carbon dioxide, making them a green energy source.

However, fission power plants create nuclear waste that remains hazardous for millions of years and requires careful storage. Fusion, on the other hand, produces no long-lived waste. The primary byproduct is helium, a harmless inert gas.

Fusion power plants also manage radioactive tritium in a closed loop, minimizing risks to the environment. Tritium has a short half-life and is used in small amounts, so it poses no long-term danger.