If all goes according to plan, the US will eliminate all greenhouse gas emissions from its electricity sector by 2035 – an ambitious goal set by Pres. Joe Biden, who relies heavily on a sharp increase in wind and solar energy generation. This plan could soon get a boost from nuclear fusion, a powerful technology that until recently seemed far out of reach.
Researchers developing a nuclear fusion reactor that can produce more energy than they consume have shown in a series of recent articles that their design needs to work, restoring optimism that this clean, unrestricted power source will help mitigate the climate crisis.
While the new reactor is still in early development, scientists hope that by the end of the decade it will be able to produce electricity. Martin Greenwald, one of the senior scientists of the project, said an important motivation for the ambitious timeline is to meet the energy needs in a hot world. “Fusion seems to be one of the possible solutions to get ourselves out of our impending climate disaster,” he said.
Nuclear fusion, the physical process that drives our sun, occurs when atoms are compressed at extremely high temperatures and pressures, causing them to release enormous amounts of energy by fusing into heavier atoms.
Since it was first discovered in the last century, scientists have been trying to use fusion, an extremely dense form of power whose fuel – hydrogen isotopes – is abundant and replenishable. In addition, fusion produces no greenhouse gases or carbon, and unlike fission nuclear reactors, it poses no danger of collapse.
Utilizing this form of nuclear power, however, proved very difficult, and it required a soup of subatomic particles, called plasma, to be heated to hundreds of millions of degrees – it is far too hot for any material container to withstand. To circumvent this, scientists have developed a donut-shaped chamber with a strong magnetic field running through it, called a tokamak, which suspends plasma.
MIT scientists and a spinoff company, Commonwealth Fusion Systems, began designing the new reactor in early 2018, which is more compact than its predecessors, and will begin construction in the first half of next year. If their timeline goes as planned, the reactor, called Sparc, will be able to produce electricity for the grid by 2030, according to researchers and company officials. This would be much faster than existing major fusion power initiatives.
Existing reactor designs are too large and expensive to generate realistic electricity for consumers. Using cutting-edge, ultra-strong magnets, the MIT and Commonwealth Fusion team hopes to make a tokamak reactor compact, efficient and scalable. “What we have really done is to combine an existing science with new materials to offer tremendous new possibilities,” Greenwald said
After the Sparc device could theoretically produce more energy than needed in the research articles published in September, the next step is to build the reactor, followed by a pilot plant that will generate electricity on the grid.
Scientists and entrepreneurs have long promised that mergers are just around the corner, just to face insurmountable problems. It has reluctance to invest in it, especially as wind, solar and other renewable energy – though less powerful than fusion – have become more efficient and cost-effective.
But the tide is changing. In Biden’s $ 2-ton plan, he cites advanced nuclear technologies as part of the carbon-free strategy, the first time Democrats have endorsed nuclear energy since 1972. There are also significant investments from private sources, including some large oil and gas companies, calling the merger a better long-term pivot point than wind and solar power.
According to Bob Mumgaard, CEO of Commonwealth Fusion, the goal is not to use fusion to replace solar and wind, but to complement it. “There are things that are difficult to do with only renewable energy, things on an industrial scale, like supplying big cities or manufacturing,” he said. “This is where mergers can come.”
The plasma science community is generally enthusiastic about Sparc’s progress, although some question the ambitious timeline, given the barriers to engineering and regulations.
Daniel Jassby, who has worked as a research scientist at the Princeton Plasma Physics Lab for 25 years, is skeptical whether a fusion reactor like SPARC will ever provide a viable alternative source of energy. Tritium, one of the hydrogen isotopes used by Sparc as a fuel, does not occur naturally and will have to be produced, he said.
The MIT team suggests that this drug will be continuously raised by the merger reaction. But Jassby believes it will require a large amount of electricity, which will make the reactor excessively expensive. “If you think we’re getting free solar and wind energy, it’s foolish to rely on fusion reaction,” he said.
Mumgaard admits that the challenges ahead are frightening. But he remains confident.
“There is a broader tendency to recognize how important climate is and that we need all hands on deck,” he said. “We’ve experienced this problem with technology, but with mergers there are great opportunities to solve it with technology.”