The power of stars to meet our energy needs? This is something to be excited about | Arthur Turrell

If you want proof that the process known as nuclear fusion can produce energy at scale somewhere in the universe, you need only look at the night sky: each pinprick of light is a natural nuclear fusion-powered reactor. For decades, scientists have sought to bring the power source of stars down to Earth and, in a stunning result recently announced, the Culham Centre for Fusion Energy in Oxfordshire has reached a new landmark in sparking and sustaining a mini star.

Scientists working on a doughnut-shaped machine called Jet, or the Joint European Torus, were able to double the previous world record (set in 1997) for energy released by fusion reactions. While the experiment ran, the output of fusion power was equivalent to four onshore wind turbines – a step towards power production at an industrial scale.

In keeping with Jet’s design and objectives, less fusion power was generated than was needed to heat the fuel. In fact, no experiment has yet yielded more energy from fusion than has been used to kick off the reactions – this remains an outstanding goal of fusion scientists around the world. What the latest results provide is a compelling indication that bigger and better star machines that work similarly to Jet, such as the internationally funded Iter project now under construction in France, will be able to produce more power than they consume.

Also important is that although this experiment only ran for five seconds, the reactions stopped not because of a disruption within the fuel, as has previously been typical, but because supporting equipment got too hot. Cryogenic cooling systems will prevent this on the next generation of machines, so the leap from five seconds to five minutes, or five hours, or even longer, now seems feasible.

Why should the rest of society care whether these scientists can recreate star power? Fusion energy has the potential to provide clean power on a planetary scale. If it can be perfected, there’s enough fuel for everyone on Earth to use as much energy annually as the average American for at least thousands of years, and probably millions. This form of power doesn’t produce carbon dioxide or long-lived radioactive waste, and there’s no chance of the meltdowns like those at Chernobyl and Fukushima. Today, energy is in short supply, is the leading cause of the climate crisis, and is being used as a dangerous geopolitical chess piece.

You may well wonder why fusion energy hasn’t yet been cracked. Reproducing conditions similar to those found in stars, where fusion thrives, is a terrifying technological challenge – perhaps humanity’s greatest ever. Fusion machines must reach temperatures between four and 10 times hotter than the sun’s core. On Jet, a web of invisible magnetic fields 80,000 times stronger than the Earth’s is needed to control and confine the fuel. The fuel itself is a swirling mass of charged particles that is susceptible to instabilities that can halt the reactions in milliseconds.

But fusion scientists are on a roll. In August 2021, a US experiment came excruciatingly close to smashing fusion’s most anticipated goal of producing more energy than was put in. Although the total energy was modest at just a 60th of Jet’s new record, the US facility beat its own previous record, set in 2018, 23 times over. In December, China’s Experimental Advanced Superconducting Tokamak (East) controlled matter at 150m degrees centigrade for 1,000 seconds, albeit without the special types of hydrogen fuel that will eventually be needed on commercial reactors. Meanwhile, there is a burgeoning private fusion industry: in the last three months of 2021, the total investment more than doubled to $4.2bn. To close out a stellar six months, Culham’s experiment has shown the world that sustained high power output from fusion reactions is possible.

Despite the momentum, there’s some way to go before fusion powers your house. Even the most flush private fusion firm is only promising a pilot plant by 2025, and the current plans for publicly funded laboratories won’t see star power on the grid for three decades. We will need fission and renewables at immense scale much, much sooner to combat the climate crisis.

Even so, it’s time to get excited about star power. Technology and research have always been the key to growing human wealth and prosperity. If fusion energy can be successfully rolled out, it will be a landmark in human history akin to the adoption of electricity or the invention of powered flight. Because our need for clean energy is acute, the sooner it does come, the better. But it will still be immensely useful regardless of when it arrives. And, as with any technology, progress doesn’t come with the passage of the years but with investment and societal will. With both, fusion could arrive sooner than we expect. Whatever the precise timeline, the advances of the past six months – and even the past week – suggest that star power has a very bright future ahead.