European scientists have set a new record for the most energy to be generated from nuclear fusion, the latest breakthrough in a decades-long effort to produce power by harnessing the reaction that powers the sun.
A team of researchers from the Eurofusion consortium produced 59 megajoules from a sustained reaction lasting five seconds — enough power to boil about 60 kettles — in an experiment at the Joint European Torus facility in Oxford, England.
“These landmark results have taken us a huge step closer to conquering one of the biggest scientific and engineering challenges of them all,” said Ian Chapman, chief executive of the UK’s Atomic Energy Authority.
JET, a collaboration between EU member states, Switzerland, the UK and Ukraine, founded in 1978, is the world’s largest, most powerful operational “tokamak” machine. The design, pioneered by Soviet scientists in the 1950s, uses powerful magnets to hold a plasma of two hydrogen isotopes — deuterium and tritium — in place as it is heated to temperatures hotter than the sun so that the atomic nuclei fuse, releasing energy.
In half a century of experiments around the world scientists have been unable to generate more energy from a fusion reaction than the power-intensive system consumes.
Arthur Turrell, whose book The Star Builders charts the multi-decade effort to achieve fusion energy, said the successful test, which more than doubles the previous energy output record of 22 megajoules, achieved by JET in 1997, was a big step forward. “In terms of power it’s equivalent to about four wind turbines . . . that’s close to industrial scale.”
Unlike nuclear fission, when atoms are split, fusion does not produce significant radioactive waste. But the biggest challenge to make fusion commercial is how to sustain the reaction and prevent it from extinguishing.
This meant sustaining the power output for five seconds was particularly significant, said Turrell. “That might not sound that impressive but five seconds is an incredibly long time on nuclear timescales,” he said.
The progress made at JET is expected to feed in to future experiments at Iter, the world’s largest nuclear fusion project, currently under construction in France at a cost of more than $20bn.
“If we can maintain fusion for five seconds, we can do it for five minutes and then five hours as we scale up our operations in future machines,” said Tony Donné, head of the Eurofusion consortium that ran the experiment.
Fusion energy has plenty of sceptics given how long it has taken to make progress but its promise as a tool to fight climate change has increased interest over the past decade.
Fusion-power would emit no greenhouse gases and supplies of the chemical inputs are essentially inexhaustible. There are approximately 5g of deuterium in every bathtub of seawater and while tritium is less accessible it can be extracted from the commonly occurring metal lithium, or generated in the reaction itself. A small glass of fuel could theoretically power a house for hundreds of years.
JET and Iter are two of several large, publicly funded fusion projects around the world but private sector money has also been flowing into fusion energy start-ups. Total private sector financing had reached more than $3bn by the end of 2021 with some of the ventures aiming to deliver commercial power in the 2030s.
George Freeman, UK minister for science, research and innovation, said the UK was committed to helping fusion energy succeed. “We are determined to make sure we adopt it in our energy mix and make clear to the energy sector that this technology is coming.”
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