LOS ANGELES: Scientists announced a breakthrough in fusion energy on Tuesday, potentially a step toward one day harnessing the process that fires the sun to generate carbon-free electricity as the world struggles with climate change.

The US Energy Department said on Tuesday that scientists at the Lawrence Livermore National Lab in California, which focuses on national security and nuclear weapons, for the first time had briefly achieved a net energy gain in a fusion experiment using lasers.

Nuclear scientists outside the lab said it seemed like the achievement would be a major stepping stone in the decades-long effort to harness fusion.

At Lawrence Livermore lab, scientists focused a laser on a target to fuse two light atoms into a denser one releasing energy.

But there’s much more science to be done.

Tony Roulstone, a nuclear energy expert at the University of Cambridge, estimated that the energy output of the experiment was only 0.5 percent of the energy that was needed to fire the lasers in the first place.

“Therefore we can say that this result ... is a success of the science, but still a long way from providing useful, abundant, clean energy,” Roulstone said.

The electricity industry cautiously welcomed the step, though emphasising that in order to carry out the energy transition, fusion should not slow down efforts on building out other alternatives like solar and wind power, battery storage and nuclear fission.

Here are some of the main issues surrounding fusion energy:

What is fusion energy?

Fusion occurs when two light atoms, such as hydrogen, heated to extreme temperatures of 100 million degrees Celsius (180 million Fahrenheit) fuse into one heavier atom, releasing large amounts of energy. It is different from fission, in which a reactor shoots a neutron into an atom of uranium, splitting into two smaller atoms.

What did scientists accomplish?

Using advanced technology, including one of the world’s largest lasers, the scientists at Lawrence Livermore focused beams on hydrogen isotope target smaller than a pea, producing a fusion reaction that for an instant generated more power that it took to start.

Scientists outside the lab said that if the preliminary results are accurate, it represents progress on work that has been going on for decades, but that fusion is not yet anywhere near producing commercial-scale power.

Will fusion help fight climate change?

Potentially. Besides vastly ramping up the energy from fusion reactions, scientists need to produce them multiple times per second on a constant basis.

Scaling that process up to a power plant and building plants big enough cover a significant chunk of the world’s growing electricity demand would take momentous efforts requiring materials, land and clear regulations for industry.

Published in Dawn, December 14th, 2022