On Tuesday morning, the Department of Energy announced that scientists at the Lawrence Livermore National Laboratory in California have had a major scientific breakthrough, reportedly with fusion. 

Scientists have been trying for years to use powerful lasers and magnets to smash hydrogen atoms together to release energy that is carbon-free. 

Billions of dollars in federal and private funding have gone into fusion research for years, with the goal of developing a clean, reliable and cheap source of power.  

Right now, there’s nothing cheap about fusion energy.

“If you’re thinking about a fusion energy plant, you’re talking about a very complicated, very expensive piece of equipment,” said Chris Fall with the nonprofit MITRE Corporation. “It’s kind of like buying a Rolls Royce at this point, as opposed to a Toyota. What we need is this sort of evolution of the technology that gets us to the lower cost.”

There’s still a long way to go on the science and technology front, before cost is figured out.

But Paul Dabbar, former Under Secretary for Science at the Department of Energy, said fusion does have the potential to one day be an affordable power source.

“The fuel is hydrogen,” said Dabbar. “Hydrogen is the most abundant element in the universe, and also on Earth. You know our ability to use that for energy in theory should be quite cheap.”

Fusion can also produce a lot of energy in a very small space and it can do it 24/7, unlike wind or solar.

Eventually, Dabbar said, once the technology to build fusion power plants gets less complicated and more affordable, buying the energy should be cheap, too.