If all goes to plan, the US will eliminate all greenhouse gas emissions from its electricity sector by 2035 – an ambitious goal set by President-elect Joe Biden, who largely relies on a surge in wind and solar power generation. That plan may soon be getting a boost from nuclear fusion, a powerful technology that until recently seemed way out of reach.
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 energy source will help mitigate the climate crisis.
While the new reactor is still in early development, scientists hope it will be able to start producing electricity by the end of the decade. Martin Greenwald, one of the project’s senior scientists, said a major motivation for the ambitious timeline is meeting energy needs in a warming world. “Merger appears to be one of the possible solutions to get out of our impending climate catastrophe,” he said.
Nuclear fusion, the physical process that powers our sun, occurs when atoms are pressed together at extremely high temperatures and pressure, releasing enormous amounts of energy by merging into heavier atoms.
Since it was first discovered in the last century, scientists have sought to harness fusion, an extremely dense form of energy whose fuel – hydrogen isotopes – is abundant and can be replenished. In addition, nuclear fusion does not produce greenhouse gases or carbon, and unlike fission nuclear reactors, there is no risk of meltdown.
However, using this form of nuclear energy has proven extremely difficult and requires heating a soup of subatomic particles called plasma to hundreds of millions of degrees – far too hot to withstand through a material container. To get around this, scientists developed a donut-shaped chamber with a strong magnetic field through it, called a tokamak, that lets the plasma hang in place.
MIT scientists and a spin-off company, Commonwealth Fusion Systems, began designing the new reactor, which is more compact than its predecessors, in early 2018, and construction will begin in the first half of next year. If their timeline goes as planned, the reactor, dubbed Sparc, will be able to produce electricity for the grid by 2030, researchers and company officials said. This would be much faster than existing major fusion energy initiatives.
Existing reactor designs are too large and expensive to generate realistic electricity for consumers. Using advanced, ultra-strong magnets, the MIT and Commonwealth Fusion team hopes to create a tokamak reactor that is compact, efficient and scalable. “What we’ve really done is combine existing science with new material to open up huge new possibilities,” Greenwald said
After demonstrating that the Sparc device can theoretically produce more energy than is needed to run in the research papers published in September, the next step is to build the reactor, followed by a pilot plant that will feed electricity into the grid. to arouse.
Scientists and entrepreneurs have long promised that fusion is just around the corner, but they run into insurmountable problems. This has led to reluctance to invest in them, especially as wind, solar and other renewable energy sources – although less powerful than fusion – have become more efficient and cost effective.
But the tide is changing. In Biden’s $ 2 billion plan, he cited advanced nuclear technologies as part of the decarbonization strategy, the Democrats’ first endorsement of nuclear power since 1972. There has also been significant investment coming from private sources, including some major oil and gas companies, which have seen merger a better hub in the long term than wind and sun.
According to Bob Mumgaard, chief executive of Commonwealth Fusion, the goal is not to use fusion to replace sun and wind, but to complement them. “There are things that are going to be difficult with renewable energy sources alone, things on an industrial scale, like powering big cities or manufacturing,” he said. “This is where fusion can come into play.”
The plasma science community is generally enthusiastic about Sparc’s progress, although some have questioned its ambitious timeline, given the engineering and regulatory hurdles.
Daniel Jassby, who spent 25 years as a research scientist at the Princeton Plasma Physics Lab, is skeptical about whether a fusion reactor like SPARC will ever be a viable alternative energy source. Tritium, one of the hydrogen isotopes that will be used as fuel by Sparc, does not occur naturally and will have to be produced, he said.
The MIT team proposes that this substance is continuously regenerated by the fusion reaction itself. But Jassby believes this requires an enormous amount of electricity, making the reactor prohibitively expensive. “When you consider that we get solar and wind power for free, it would be foolish to rely on a nuclear fusion reaction,” he said.
Mumgaard admits that the challenges ahead are daunting. But he remains confident.
“There is a broader trend to recognize how important the climate is and that we need all hands on deck,” he said. “We got into this problem with technology, but with fusion, there are great opportunities to solve it with technology.”