Business & Tech

MIT says nuclear fusion as a practical energy source is less than two decades away

The  site of the ITER project in southern France. The fusion reactor is expected to go online in 2025.
Associated Press
The site of the ITER project in southern France. The fusion reactor is expected to go online in 2025.

The Massachusetts Institute of Technology and a new company founded by the school’s scientists believe they are less than two decades away from turning nuclear fusion into a practical energy source. And an Italian oil company is investing $50 million to see if they’re right.

Maria T. Zuber, MIT’s vice president of research, said the program could “change the trajectory of climate change” by providing a method of producing almost limitless electric power while creating no planet-warming greenhouse gases. Zuber said it will take the better part of a decade to prove whether the new reactor design, called SPARC, will work. But Zuber added, “if we succeed, the world’s energy systems will be transformed.”

MIT will tackle the task alongside Commonwealth Fusion Systems, a spinoff founded by the school’s researchers and based on technology developed at the Plasma Science and Fusion Center. Initial funding for the program will be provided by Eni, an Italian oil and gas company that had $82.5 billion in revenues last year. Eni is a member of the MIT Energy Initiative, a research alliance between the university and many of the world’s leading energy producers. It was through Eni’s involvement in the initiative that the company learned about SPARC, and decided to invest.


“Eni certainly does produce oil,” said Zuber, “but they view themselves as an energy company and they’re actually looking very aggressively at diversifying their energy portfolio.” MIT is also seeking additional private sector investment to keep the project going.

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Today’s nuclear power reactors split atoms, a process that leaves behind lots of radioactive waste. A fusion reactor works by forcing two hydrogen atoms to become a single helium atom, a process that releases subatomic particles that generate intense heat. Nuclear fusion drives the sun and stars, and hydrogen bombs. A commercial fusion reactor would use the same power source to boil water into steam and turn electrical generators. Fusion reactors would be safer to operate and would generate much less radioactive waste than fission reactors. But after more than half a century and research costs in the billions, no one has managed to make fusion reactors work — not even MIT, which has built three experimental ones.

“We’ve never reached what we call fusion burn, where the fusion reaction self-sustains the plasma,” said Ian Chapman, chief executive of the UK Atomic Energy Authority .

The most promising effort at present is the International Thermonuclear Experimental Reactor or ITER, based in France and funded by the European Union, Russia, China, and the United States, among other nations. If it goes online in 2025, as expected, “ITER will be the first demonstration of fusion power on a commercial scale,” said Chapman. It’s designed to put out 500 megawatts, enough to power about 360,000 typical US homes.

But ITER is an immense machine that’s expected to cost $22 billion. MIT scientists believe their SPARC design points the way to much smaller and cheaper fusion reactors.


A fusion reaction can happen only if hydrogen atoms are heated to millions of degrees, heat that would vaporize any man-made or natural material. So the reaction must be contained inside a intense magnetic field generated by electromagnets. With existing magnet technology, immense magnets are needed to generate a sufficiently strong field.

SPARC will try to solve this problem by using a type of magnetic material containing barium and copper oxide that generates a field four times more intense than other magnetic compounds. This will enable them to shrink the magnets and the reactors, making fusion a practical choice for developing countries, and the world’s wealthy nations. “By making it a much smaller reactor, we can fit it to many markets around the world,” said Robert Mumgaard, chief executive of Commonwealth Fusion Systems.

In addition, the reactor’s more intense magnetic field will let it generate 10 times as much power as a reactor of the same size using existing magnet technology. SPARC is expected to generate only about 100 megawatts, one-fifth the power of ITER, but in a much smaller space. A commercial version producing twice as much power, 200 megawatts, could be ready to test within 15 years.

Dennis Whyte, director of the Plasma Science and Fusion Center, said a commercial version of SPARC might cost about $1 billion. By contrast, two nuclear reactors under construction in Georgia were expected to cost $14 billion.

Fusion has captured the imagination of other private sector investors. TAE Technologies, a California company backed by Microsoft Corp. cofounder Paul Allen, is working on a fusion reactor and has recruited Alphabet, the parent company of search engine Google, to develop software for the project. The famed “Skunk Works” lab of defense contractor Lockheed Martin is also trying to build a fusion system.


“We’re seeing what’s looking like the beginning of a fusion moment,” Mumgaard said.

Hiawatha Bray can be reached at Follow him on Twitter @GlobeTechLab.