...AND CHEAPER...:

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]."

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