Researchers developing a nuclear fusion reactor that can generate more energy than it consumes have shown in a series of recent papers that their design should work, restoring optimism that this clean, limitless power source will help mitigate the climate crisis.

While the new reactor still remains in early development, scientists hope it will be able to start producing electricity by the end of the decade. [...]

MIT scientists and a spinoff company, Commonwealth Fusion Systems, began designing the new reactor, which is more compact than its predecessors, in early 2018, and will start construction in the first half of next year. If their timeline goes as planned, the reactor, called Sparc, will be capable of producing electricity for the grid by 2030, according to researchers and company officials. This would be far faster than existing major fusion power initiatives.

Existing reactor designs are too large and expensive to realistically generate electricity for consumers. Through the use of cutting-edge, ultra-strong magnets, the team at MIT and Commonwealth Fusion hope to make a tokamak reactor that is compact, efficient and scalable. "What we've really done is combine an existing science with new material to open up vast new possibilities," Greenwald said

Having demonstrated that the Sparc device can theoretically produce more energy than it requires to run in the research papers published in September, the next step involves building the reactor, followed by a pilot plant that will generate electricity onto the grid.

Scientists and entrepreneurs have long made promises about fusion being just around the corner, only to encounter insurmountable problems. This has created reluctance to invest in it, particularly as wind, solar and other renewables -- although less powerful than fusion -- have become more efficient and cost effective.

But the tide is changing. In Biden's $2tn plan, he named advanced nuclear technologies as part of the decarbonization strategy, the first time the Democrats have endorsed nuclear energy since 1972. There is also significant investment coming from private sources, including some major oil and gas companies, who see fusion as a better long term pivot than wind and solar.

According to Bob Mumgaard, chief executive of Commonwealth Fusion, the aim is not to use fusion to replace solar and wind, but to supplement them. "There are things that will be hard to do with only renewables, industrial scale things, like powering large cities or manufacturing," he said. "This is where fusion can come in."