Nuclear fusion is getting more attention. The US Department of Energy said this week that it had achieved a major scientific breakthrough in fusion power research. We've heard about fusion progress before. It has been said that we are close to generating all the clean energy we will ever need from nuclear fusion.

A big breakthrough in fusion power research.

This guide to fusion power was put together with the help of some experts. Scientists dream of fusion, as well as the harsh realities the technology faces to bring the power of fusion from scientific ambition to commercial reality.

What is nuclear fusion?

Nuclear fusion has been a goal for a long time. It seems like it's sort of simple. Our Sun creates its own energy through a process called fusion, in which atoms are fused together at high temperatures and pressures. This usually involves hydrogen atoms joining together. Scientists on Earth want to duplicate the reaction in a controlled way because it releases a lot of energy. There is a hydrogen bomb.

How is nuclear fusion different from nuclear fission?

Nuclear power plants generate electricity through a process called fission, which is different from fusion. Energy is released by splitting atoms.

What are the advantages of nuclear fusion?

The possibilities are endless once humans figure out how to make nuclear fusion happen. The most abundant element is hydrogen. It can be obtained from seawater. As much energy as 300 gallons of gasoline can be generated by a single gallon of seawater.

Nuclear Reactors have a lot of mess to clean up. Nuclear fusion leaves behind radioactive waste. The US doesn't know what to do with nuclear waste for millions of years.

These problems don't exist in fusion. You can build new atoms with fusion, like the stuff in balloons. It doesn't produce greenhouse gas emissions This is a potentially unlimited energy source that doesn't rely on the weather, which is still a challenge with renewable energy.

Why haven’t we been able to make ignition happen?

It's difficult to recreate a star in a lab. You need a lot of pressure and heat. Extreme pressure is needed for fusion to take place in the sun's environment. Scientists on Earth don't need that kind of pressure to get the same reaction because they don't have it. That has taken more energy than scientists have been able to generate through fusion.

It takes a lot of money and technology. It is amazing that we have made any scientific progress at all. Commercializing it would be a good idea. We will talk about some of the other issues in a little while.

What’s this new “nuclear fusion breakthrough” everyone’s talking about?

In the early hours of Monday, December 5th, researchers at the Lawrence Livermore National Lab achieved the first fusion ignition on Earth.

The White House Office of Science and Technology Policy Director said at a press conference that more energy was released from the fusion ignition than the energy of the lasers going in.

A chamber filled with laser equipment
The target chamber of LLNL’s National Ignition Facility, where 192 laser beams delivered more than 2 million joules of ultraviolet energy to a tiny fuel pellet to create fusion ignition on December 5th, 2022.
Image: Lawrence Livermore National Laboratory

The fusion experiment yielded 3.15 megajoules of energy compared to 2.05 megajoules. There was a 1.5 gain in energy. It was an important first for fusion research.

How did they do that?

The largest and highest-energy laser system was used by researchers. The NIF is large enough to fire 192 powerful laser beams at a single target. To reach fusion ignition, 192 laser beams squeeze fuel within a diamond capsule that is 100 times larger than a mirror. Some of the hydrogen strontium that was held in the capsule was used to generate energy. About 4% of the fuel was turned into energy.

Lasers are neat. Tell me more about the diamonds, too.

The Target Fabrication Program manager at Lawrence Livermore National Laboratory said that the fuel capsule needs to be as perfect as possible. We still have tiny flaws on our shells, smaller thanbacteria, and so we've yet to get there.

When it comes to the target and its implosion, symmetry is very important. When it comes to the target, you need to keep in mind that the lasers need to be aligned correctly and that you need to blast your target with intense pressure and heat. It is like putting a basketball down to the size of a pea in order to maintain a perfect spherical shape. You waste a lot of energy if you deviate from that shape.

Does this mean we’re going to have nuclear fusion power now? 

Not by a large margin. The lab achievedignition using a limited definition of a "net energy gain" focused on the output of the laser The 300 megajoules of energy that the lasers shot at their target was eaten up by the grid. There was a lot of energy lost in this experiment.

A 1.5 net energy gain is not enough to build a fusion power plant. A gain of 50 to 100 is required.

So, where do we go from here?

A lot of work needs to be done. Researchers are constantly trying to make more precise targets. This is a lot of work. A single pellet target could cost $100,000 today according to University of Chicago theoretical physicist RobertRosner. NIF has an External Advisory Committee. If a fusion reactor needs a million pellets a day, the cost per pellet needs to be less than a dollar.

If you want to use lasers again, you will need a setup that is more efficient. 1980s laser technology is the basis of the NIF. The National Ignition Facility was built in 1997 and it wasn't operational until 2009. The NIF is able to shoot its laser once a day. A fusion power plant would need to shoot 10 times a second.

This is a single igniter capsule. Kim Budil said at the press conference that to realize commercial fusion energy, you have to do a lot of things. There are a lot of hurdles in technology.

Are there other ways to fuse atoms together?

Lasers aren't the only strategy used to start a fire. A device called a tokamak can be used to confine the fuel. It can be cheaper to build a tokamak. Private companies have built tokamaks, so more research has been done in this area.

The tokamak hasn't reached ignition. It has the ability to sustain a fusion reaction for a long time. The fusion reactions occur within a fraction of a second.

What does reaching “ignition” actually accomplish, then?

A physics professor at Queen's University said they reached the top of the hill. Even if there is still a long way to go, achieving ignition was the most difficult step in fusion power research.

It's more of a scientific breakthrough than it is a practical application for our energy system.

When it comes to nuclear defense, reaching ignition could have an immediate impact.

Wait, what’s this about nuclear weapons?

Experiments that would allow the US to maintain its nuclear weapons without having to blow them up were the initial idea. The Comprehensive Nuclear- Test-Ban Treaty ended underground test explosions. The ground was broken the next year. In its December 5th experiment, it was finally able to achieve nuclear ignition, which is similar to the fusion that occurs when a nuclear bomb explodes. Researchers hope that reaching ignition in a controlled way in a lab will allow them to verify the computer models that they have developed.

Cut to the chase. When are we going to have nuclear fusion power plants?

We might have the first fusion power plant in a decade, according to the most optimistic experts. Most experts think that fusion power is still many decades away.

Is this going to solve climate change?

We can't afford to wait a decade or more for fusion power to clean up pollution from our energy system Research shows that the world needs to cut greenhouse gas emissions to net zero by the year 2050 in order to keep global warming from reaching a point of difficulty. Carbon dioxide emissions from fossil fuels need to be halved by the year 2030. fusion research has never been able to achieve that speed.