Nuclear fusion seems hot right now — but how close is fusion power?

Nuclear fusion milestones from Canada's General Fusion and China's EAST reactor have caused a buzz over this potentially limitless, clean energy source becoming a reality amid rising power demand from AI and electrification. Meanwhile, new fusion startups have been popping up around the world and have drawn billions in private investment.

Here's a closer look at nuclear fusion and where its development is at in Canada and the world.

Nuclear fusion has been researched for decades as a way of producing clean, safe, limitless energy from an abundant source.

Fusion happens when nuclei at the centres of two atoms combine into a single nucleus, forming a heavier element and releasing a huge amount of energy. Combining hydrogen nuclei into helium powers our sun. The same reaction can be used in reactors on Earth.

Hydrogen, the fuel for that reaction, is widely available in water on Earth. And unlike the reactions in traditional nuclear reactors, which split atoms of radioactive elements such as uranium, fusion reactions don't generate radioactive waste. But commercial nuclear fusion reactors are not yet available.

China's EAST (Experimental Advanced Superconducting Tokamak) fusion reactor recently reached an important milestone. Fusion reactors need to keep hydrogen extremely hot and condensed, in the form of plasma, as it's found in the sun. The Chinese Academy of Sciences announced earlier this month that EAST had kept plasma stable at densities beyond a previous limit. That may enable the production of smaller, cheaper commercial fusion reactors in the future, Nature reports. 

Robert Fedosejevs, a University of Alberta professor who has been involved in laser fusion research for more than 50 years, said those results had been predicted years ago, although actually doing it is "a step forward." 

A November 2024 announcement from General Fusion, based in Richmond, B.C., also resurfaced in the news this month, which is described as a "world record" in the production of neutrons — byproducts that show how much fusion occurred.

Fedosejevs said the record applies only to General Fusion's own technology — some government-funded fusion reactors have done orders of magnitude more fusion with other technologies. However, he added, General Fusion is "farther along than most [fusion] startups who've not produced neutrons at all."

Both recent developments are important, but incremental, said Blair Bromley, past-co-chair of the Fusion Energy and Accelerator Science and Technology Division of the Canadian Nuclear Society.

In other Canadian fusion news, a new Centre for Fusion Energy in Ontario was announced less than two months ago. It will be established with $33 million from the federal government and Crown corporation Atomic Energy of Canada Ltd., $19.5 million from the Ontario government and Crown corporation Ontario Power Generation, and $39 million from fusion startup Stellarex Group Ltd. Stellarex says the centre's mission would include the design, construction and operation of a demonstration reactor, but has offered no timeline.

Andrew Holland is CEO of the Fusion Industry Association (FIA), a global organization that says it represents all the major private fusion companies in the world outside China. 

Holland said investors around the world are thinking about climate change and energy security amid growing demand for energy from data centres and AI: "Ideally, we need a lot more carbon-free, always-on, always available energy. Fusion can solve that."

Meanwhile, "the science has progressed to the point where … companies are confident that the next machine they build will work," he said.