Nuclear fusion: set your controls for the heart of the sun

In a landmark breakthrough, a British reactor has smashed the record for the amount of fusion-generated power produced in one go, bringing the prospect of plentiful, green energy a big step closer to becoming reality.

The doughnut-shaped crucible at Oxfordshire’s JET laboratory was able to produce twice as much energy as its previous record, set in 1997, by heating and fusing together two versions of a hydrogen atom at 100 million °C, the same process that powers the sun. The plasma used in the experiment became the hottest substance in the solar system for five seconds.

It’s a big deal because fusion’s potential is enormous. Scientists have been hoping for years that the technology might answer the world’s energy needs as it offers the prospect of virtually unlimited zero-carbon power. Fusion produces far less radioactive waste than traditional fission reactors and 10 million times more energy than coal, oil or gas per gram of fuel – deuterium and tritium – which are both plentiful.

But there’s still a long way to go. The JET experiment consumed far more energy than it produced. Even so, experts see it as a big leap forward, not least because it justifies design decisions for the ITER, a fusion mega-project under construction in Saint Paul-lez-Durance, southern France, and backed by a consortium of countries. It is due to open in 2025. “These experiments we’ve just completed had to work,” said JET’s chief executive, Prof Ian Chapman. “If they hadn’t then we’d have real concerns about whether ITER could meet its goals. This was high stakes and the fact that we achieved what we did was down to the brilliance of people and their trust in the scientific endeavour.”

The breakthrough comes at an interesting moment, with global gas prices sky-rocketing and much of the developed world transitioning to green energy. Fusion’s success could shift the debate in Europe and beyond on whether nuclear power should be part of the solution.

Britain’s leading role in developing fusion technology means it’s well-placed to reap the rewards. Yet on the Continent, France and Germany stand on opposite sides of a rift over nuclear. While France has for a long time been keen on atomic power – which accounts for three quarters of its electricity – Angela Merkel committed to retiring all of Germany’s nuclear reactors by 2022 in the wake of the Fukushima disaster.

Germany is now caught between its rejection of nuclear power and its green energy commitments, not to mention energy security fears, brought into sharp relief by the gas crisis and the prospect of Vladimir Putin turning off the taps if he acts in Ukraine.

Even though it’s unlikely we’re going to be heating our homes with fusion power until the 2040s, energy policy works over long time horizons. Tomorrow’s energy must be planned for today. And this latest breakthrough in star power could well change the equation.