What the fusion breakthrough means for clean energy

This breakthrough demonstrates the fundamental viability of fusion power, which researchers have sought since the 1950s. But the scientific experiment required the most powerful lasers in the world and is not an immediately practical route to fusion power. . Many more scientific and technical breakthroughs will be needed to take fusion from a laboratory experiment to a commercial technology that could deliver reliable, carbon-free power to the grid.

In fusion reactions, whether in a reactor or in the core of a star, atoms smash against each other until they fuse, releasing energy. The purpose of fusion energy is to get more energy from the fusion reaction than is put in to energize and hold the fuel in place, in a controlled manner. So far, this has never been demonstrated.

The fusion reaction at NIF achieved this, generating 3.15 megajoules of energy, more than the 2.05 megajoules provided by the lasers used in the reactor. Last year, the same installation produced about 70% of the energy supplied to the reaction by the lasers. Lasers require more energy to operate than they supply to the reactor, but even seeing a net energy gain in the system is a big step.

“It puts a lot of wind in the sails of the community,” says Anne White, head of nuclear science and engineering at MIT. But, she adds, that doesn’t mean we’ll see fusion power on the grid tomorrow: “It’s not realistic.”

The lab uses the world’s largest and most powerful laser in an approach to fusion called inertial confinement.

Although inertial confinement is the first fusion scheme to produce a net energy gain, it is not the most likely route for potential commercial fusion efforts. Magnetic confinement, specifically a doughnut-shaped reactor called a tokamak, is seen by many fusion scientists as the main way forward.

The net gain observed in the inertial confinement experiment does not translate to other approaches to fusion energy, such as a tokamak. The physics and engineering needed to get there are different for different concepts, White says.