For the last century, physicists have tried to harness the power of nuclear fusion, the energy released when two atoms are joined, and have so far been unable to build a reactor that’s powerful enough to generate more energy than it needs to keep running. But now, researchers are getting closer than ever.

The longest, running experimental reactor, the Joint European Torus (JET), has been instrumental in facilitating scientists’ journey to making fusion energy a reality by cementing which exact hydrogen isotopes (deuterium and tritium) will serve as the best fuels. From these findings, scientists and 35 nations have joined forces to build ITER in southern France. At twice the diameter of JET, the reactor will be capable of creating 10 times the energy required to start its process.

The UK’s Culham Centre for Fusion Energy in Oxfordshire is where JET is located. It’s also home to the nation’s effort and a magnet for those in the private sector who see fusion energy’s potential to solve the world's energy crisis. Some have likened the area to California’s Silicon Valley as another hotbed of innovation.

Why This Matters

As climate change intensifies, fusion energy could become a valuable source of low-carbon generation. Many climate organizations argue that nuclear power is essential to meeting energy demands and lowering emissions. The IPCC included nuclear power in all four of its plans to reduce emissions. The International Energy Agency (IEA) also promotes nuclear power, emphasizing that by 2050, 90% of electricity will be generated by renewables, and about 30% will come from nuclear power.

Moreover, energy demands are skyrocketing as blistering heatwaves hit worldwide. People are cranking air conditioning units to keep cool. At the same time, prices at the pump have soared in the wake of Russia’s war on Ukraine. As countries prioritize energy security, they are rethinking how to import fuel from foreign powers and more sustainably satisfy their nations’ demands. Nuclear fusion could be the key, as it uses replenishable fuel to provide an unlimited, steady torrent of energy without releasing carbon or toxic waste.

Fusion Ain’t Easy

The sun is the best example of a natural fusion reactor. Below its surface, temperatures reach 15 million degrees Celsius. Such high heat, pressure, and density are the perfect environment for fusion to occur. But recreating these conditions on Earth is a massive challenge, if not impossible. Instead, nuclear reactors like JET heat up to more than 150 million degrees Celsius.

Another complexity of nuclear fusion is high radiation and maintenance. Once operating, reactors are no longer accessible to humans, so researchers are developing sophisticated AI and robotic arms to control and maintain conditions for reactors.