Nuclear fusion energy could be “even more important than the industrial revolution” but offers no quick wins for investors and will need smart collaboration between the private and government sectors to unlock its massive potential, said an expert backing companies in the field on behalf of billionaires such as Bill Gates and Jeff Bezos.

“Fusion is one of those technologies that totally changes the game,” said Phil Larochelle, a partner at Breakthrough Energy Ventures, the fund set up by Gates to invest in key energy transition innovations that also has the Amazon founder and a string of other ultra-rich investors on its books.

Larochelle said of fusion, which aims to harness the reactions that power the sun to produce unlimited, on-demand, zero-carbon energy (see panel): “In the annals of human history you’ll have… 300 years where we were burning fossil fuels and doing chemical reactions.

“Once we get the first fusion reactors, we’ll be building better fusion reactors for 10 million years.”

Larochelle, a physicist who has previously worked on energy technology projects for Google, said scientific advances in fusion and progress among the small but growing number of start-ups active in the sector had made a “why now” case to investors such as Breakthrough, which has so far backed four fusion technology companies.

“People are now willing to believe this could happen – but now we need to have to take a sober look and say ‘it could happen, what has to happen for it to get across the finish line’,” he told the FusionX Invest conference in London.

Breakthrough applies a rule of thumb for clean power investments that they should offer a pathway to delivering electricity to the grid for less than $50/MWh, said Larochelle.

The 20-year fund invests on behalf of “very high net-worth individuals. They care of course about returns, but they also care about impact,” he said. “If your technology is wildly successful, can you reduce at least 1% of world greenhouse gas emissions?”

He added that as far as investors are concerned, “this is something where the real payoff is probably going to come in the 2030s”.

Given its much vaunted potential as the energy transition’s ‘magic bullet’, fusion’s pioneers are the subject of huge interest – and often scepticism – over how fast they can start delivering commercial power, with one player in the market claiming last week it was set to do so by 2028, with Microsoft lined up as its first customer.

Larochelle told the industry event in London: “If things go well, we think there a chance you can get electrons on the grid in the 2030s.”

Finding the many billions needed for scale-up of fusion energy generation and its supply chain will need creative collaboration between private capital and governments, said the Breakthrough executive.

But he added that fusion would be indispensable as a way to deliver the epic increases in power needed not just to decarbonise the planet, but to support equitable economic growth.

“Today the world’s electricity capacity is about 6TW – if you want everyone to be as wealthy as the west… you need 20TW.

“If everyone wants to be both sustainable and wealthy, you would love to have the arrow of fusion in your quiver.”

Nuclear fusion - star power on earth

Nuclear fusion energy aims to harness the same reactions that power the sun to produce unlimited, on-demand, clean energy.

The process involves changing a gas to a plasma at temperatures of tens of millions of degrees, often aided by superconducting magnets, to create collisions between hydrogen atoms, tapping the energy that’s produced.

Unlike its close cousin nuclear fission – basis of the current global nuclear industry, which relies on splitting rather than combining atoms – fusion is said by scientists to present no risk of the sort of runaway reaction that led to the Chernobyl disaster.

And while it is not waste-free, the by-products are said to be low and short-lived compared to fission, and much more easily manageable.