Could fusion help fight climate change?

U.S. scientists on Tuesday announced a breakthrough in fusion energy, which could be a step toward one day generating carbon-free electricity from the sun as the world grapples with climate change.

Here are some main questions surrounding fusion energy:

What is fusion energy?

Fusion occurs when two light atoms, such as hydrogen, are heated to extreme temperatures of 100 million degrees Celsius (180 million degrees Fahrenheit) and then fuse into a heavier atom, releasing enormous amounts of energy. It differs from fission, in which the reactor fires a neutron into a uranium atom, splitting it into two smaller atoms.

What have scientists achieved?

Using advanced technology, including one of the world’s largest lasers, Lawrence Livermore scientists focused the beam on a hydrogen isotope target smaller than a pea, creating a fusion reaction that instantly produced more energy than it started energy needed.

Scientists outside the lab say the initial results, if accurate, represent progress in work that has been going on for decades, but such fusion is nowhere near producing electricity on a commercial scale.

Tony Rulstone, a nuclear energy expert at the University of Cambridge, said the experiment appeared to be successful because the energy output released by the reaction exceeded the energy delivered by the laser to the target. But the energy output of the experiment was only 0.5 percent of the massive amount of energy needed to fire a laser. “One of the engineering goals of fusion is to recycle most of the energy used in the process and get an energy gain of twice the laser energy,” Roulstone said.

Can fusion help fight climate change?

Potential. In addition to dramatically increasing the energy from fusion reactions, scientists also need to generate them on a constant basis many times per second.

Scaling up the process to power plants and building plants large enough to meet a significant portion of the world’s growing electricity demand will require enormous effort, requiring materials, land and clear industrial regulations. Politicians who favor existing fuels and infrastructure are likely to resist rapid change.

With the quest for fusion power a decade or more underway, countries should continue to aggressively move into wind and solar power, energy storage (including batteries), next-generation fission power and other alternatives, scientists and environmentalists say to reduce dependence on fossil fuels.

One of the big advantages of fusion is that it is likely to produce very little radioactive waste compared to fission.

What other types of fusion energy are being developed?

Private companies have raised about $5 billion from investors including individuals, oil companies and public money, according to the Fusion Industry Association. Eight companies, including Focused Energy and First Light Fusion, aim to use lasers to initiate fusion reactions.

About 15 companies, including Commonwealth Fusion Systems and TAE Technologies, aim to use powerful magnets to confine fusion fuel in the form of plasma, the fourth state of matter that contains charged particles. About 10 companies are experimenting with other approaches, including a combination of magnets and lasers.