For years, the science has proved difficult to master. But over the past year, nuclear fusion has inched closer to reality.
Scientists are mere years from getting more energy out of fusion reactions than the energy required to create them, they said. Venture capitalists are pumping billions into companies, racing to get a fusion power plant up and running by the early 2030s. The Biden administration, through the Inflation Reduction Act and the Department of Energy, is creating tax credits and grant programs to help companies figure out how to deploy this kind of energy.
Yet challenges remain, according to nuclear scientists. The U.S. energy grid would need a significant redesign for fusion power plants to become common. The price of providing fusion power is still too high to be feasible.
“We’re at a very exciting place,” said Dennis G. Whyte, director of MIT’s Plasma Science and Fusion Center. “But we also have to be realistic in the sense that it’s still very hard.”
The quest for nuclear fusion technology started around the 1950s. Soviet scientists designed a machine called a tokamak — a doughnut-shaped device that uses magnetic fields to confine plasma and heat it to the outrageously high temperatures needed for hydrogen nuclei to smash together.
In the years following, several countries decided that nuclear fusion energy would be a boon for the world, but they would need to collaborate to make it a reality. In the 1970s, European countries began working on a fusion experiment, called Joint European Torus. In the 1980s, the United States and the Soviet Union decided to cooperate to harness fusion energy for peaceful purposes, creating an international collaboration called the International Thermonuclear Experimental Reactor.
Together, the countries made strides in fusion science, Whyte said, and figured out fundamental principles of how to heat and keep plasma at temperatures broaching 150 million degrees Celsius (300 million degrees Fahrenheit) to sustain fusion reactions. But over the past two decades, the pace of progress on these international projects has slowed, he added, noting that they are complex, multinational endeavors.
As the quest for climate change solutions has become more pressing, more than a dozen private-sector companies have stepped in, with many trying to get a fusion power plant to market by the 2030s. They have a range of approaches, Whyte said, with some using magnetic fields to get plasma hot and stable enough to sustain fusion reactions, while others implode tiny pellets of hydrogen atoms to create fusion reactions.
A handful of these companies have made promising achievements in the past few years, which have enabled them to raise unprecedented levels of cash.
Commonwealth Fusion Systems, a company spun out of MIT, raised $1.8 billion in December. That came nearly three months after it tested a magnet for its tokamak machine that will allow it to achieve “net energy,” meaning the machine will be able to make more fusion energy than it takes to sustain reactions.
With the cash, the company is building a facility in Devens, Mass., to build and house a full-scale model of the machine, called SPARC, which is slated to be fully operational by 2025. If that model can achieve net energy, the company plans to build a fusion power plant by the early 2030s, which could plug into the energy grid and begin providing power to homes.
Bob Mumgaard, the company’s chief executive, said that’s when government collaboration will really help. His company probably will need financial assistance from the Department of Energy’s loan program office to fund its power plant, Mumgaard says. The office got funding from the Inflation Reduction Act and has roughly $40 billion in loans available to help fund energy projects that are proven to work but might have a hard time raising money from banks.
“Once the technology is shown to work,” Mumgaard said, “it’s less risky, and the next buyer of that technology could get a commercial loan.”
Phil Larochelle, a partner at the venture capital firm Breakthrough Energy Ventures, said private money is flowing into fusion at such high levels because scientific advancements, such as better magnets, have made cheap nuclear fusion a likelier possibility.
Going forward, Larochelle noted that getting nuclear fusion to market probably will require formal cost-sharing programs with the government, which he said could be similar to how NASA is partnering with SpaceX for space travel innovation.
“In both the U.S. and the U.K., there’s now kind of new government programs and support for trying to get to a [fusion] pilot,” he said. “It’s a good kind of risk-sharing between public and private [sectors].”
Despite the growing government collaboration, Whyte said, a few challenges remain.
The effects of climate change are increasingly irreversible, and the clock is ticking, he said, making fusion energy a crucial need. Companies will have to figure out how to deploy the technology widely. Doing it cheaply is most important, he said. “What I worry about is that we’ll get to a system where we can’t actually make it economically attractive fast enough,” he added.
Moreover, to create an electricity grid through which fusion technology provides large amounts of power, many things need to happen. Universities need to churn out scientists more capable of working on fusion technology. Fusion power companies need to build devices that create more energy than they consume. Scientific and manufacturing materials must be constructed in difficult ways if power plants want to scale.
“Can we get there?” Whyte asked. “I think we can if we get our act together in the right way. But there’s no guarantee of that.”
