Summary

Nuclear fusion remains an elusive energy solution despite decades of research and optimism, with significant scientific and financial challenges still to overcome.

Abstract

Nuclear fusion, often heralded as the future of clean energy, has been a subject of interest and investment since the mid-20th century, yet it remains out of reach. Despite the promise of abundant, sustainable energy, the technology faces daunting technical hurdles, such as achieving a Q factor of 1 or higher, where the energy output equals or exceeds the input. The two primary methods of confinement, magnetic and inertial, have seen incremental progress, but neither has led to a scalable, energy-positive fusion reaction. Historical attempts to harness fusion have been marked by periods of enthusiasm followed by setbacks, with the oil crises of the 1970s being a notable driver of renewed interest. Although current advancements are promising, with a ten-thousand-fold improvement in plasma performance and a factor of 10 away from replicating the core conditions of a fusion power plant, the consistent projection of fusion being "20 years away" reflects both genuine scientific confidence and the need for ongoing funding and public support.

Opinions

The public and scientists have historically been optimistic about nuclear fusion's potential to revolutionize energy production.
Private companies have been more skeptical due to the high costs, complexity, and risks associated with nuclear energy projects.
There is a consensus that nuclear fusion offers significant advantages over fission, including safety, fuel availability, and environmental impact.
The consistent projection of fusion being 20 years away is seen as a necessary optimism to maintain funding and interest in the technology.
Despite the challenges, there is a belief among scientists that progress is being made and that fusion is closer to realization than ever before.

How Close to Nuclear Fusion Are We Really?

We’ve been promised that if we can crack nuclear fusion, it will change our lives for the better. There are promises of abundant energy and a new sustainable future. It’s the holy grail of clean power, they say. No doubt utilizing the stuff that powers stars will be a game-changer for the human race, but how soon can we expect this massive upgrade?

You’ve probably heard that we’re right on the cusp of nuclear fusion, it’s just around the corner, and certainly no more than 20 years away! Your children will live in a world where nuclear fusion is the norm and they will be baffled how we didn’t figure it out sooner! Well, your parents probably heard that too, and maybe even their parents. So what’s the holdup?

To understand why the tech is just around the corner and always will be, we first need to understand what nuclear fusion is and how we came to know about it.

A Nuclear History Lesson

In 1897 JJ Thomson discovered the electron and created the first model of an atom. We went from a basic understanding of an atom to discovering the nuclear fission of heavy elements by 1938. Only 7 years later, in 1945, an American B-29 bomber dropped the world’s first atomic bomb. We figured out nuclear fission in an infinitesimal amount of time, so surely fusion would be just as quick, right? That’s what many people thought, anyway.

In the years following World War II and into the 1950s, nuclear fission had been rebranded as an exciting technology destined to solve all of our energy needs, rather than a scary weapon of war. Public attitude towards nuclear at this time was positive and for the most part, scientists and the public thought nuclear was the future!

However, private companies weren’t so convinced, and the industry needed their investment. Although nuclear energy has advantages over coal and gas, it’s very expensive to get up and running, and also very complex. This means planning to build a plant can take years, eat lots of money, and require highly skilled engineers. This all seemed too much of a headache and too risky for many investors and nuclear fell out of favor for a while.

Nuclear came back strong in the 1970s when the conflict in the middle east meant that oil prices skyrocketed. Nuclear no longer seemed as risky, but rather as a good way to become more independent. Nearly half of all nuclear reactors in the world were built between 1970 and 1985! But we’re now some time on from the 1980s, and even after several nuclear hype cycles, we don’t have nuclear fusion, so what gives?

Where Are We Now?

We can heat hydrogen atoms to astronomically high temperatures, and we can create fusion reactions…we just can’t scale it up. A nuclear plant (whether it’s fission or fusion) needs power to run, and at the moment, the fusion reactions we make cost more energy than they produce. This is called the Fusion Energy Gain Factor and is expressed using the equation Q=Pfus/Pheat. A Q factor of 1 would mean that you breakeven. A Q factor of 2 would mean that you double the energy you put in. Anything less than 1 means that you put more energy in than you get out. We have never achieved a Q factor of 1. The current record is held by the European tokamak JET (UK), which succeeded in generating a Q factor of 0.67 in 2017.

There are currently two ways to create fusion reactions, magnetic confinement, and inertial confinement. The key difference between these technologies is how we get the fuel to the temperatures and densities required for fusion to occur.

Magnetic Confinement

This is where hydrogen gas is contained using magnets rather than a physical container. The temperatures required to excite the hydrogen atoms to the level of colliding with each other are extreme. At these extreme temperatures, almost all physical “bottles” would break down. Magnetic confinement allows for more sustained nuclear reactions but isn’t without its problems.

A major issue with magnetic confinement is that it’s very difficult to stop these “magnetic bottles” from leaking. There are no known magnetic field geometries that can completely contain the plasma.

Inertial Confinement

This is an area of nuclear fusion research that focuses on creating a quick fusion burst via LASERs. A fuel palette composed of hydrogen isotopes is placed in a large chamber. LASERs are then fired onto the palette to create a quick burst of high pressure and temperature.

Both methods are challenging, but have come on a long way since the 1950s.

Why Are We Always 20 Years Away?

You might have heard the phrase “nuclear fusion is 20 years away and always will be”. For around 75 years now, there have been consistent hype cycles in the news about nuclear fusion technology. But, if we are still a long way off getting a Q of 1 or above, then why are scientists so confident that it’s always just around the corner? In truth, they aren’t, but like a lot of other areas in life, it pays to be confident. Nuclear Fusion has some impressive benefits, namely:

Safety benefits over fission: Nuclear fusion doesn’t produce dangerous radioactive isotopes. The reactions are also easier to control.
Fuel source: Deuterium and tritium can be used as fuel sources, which means we can use the abundance of seawater available on Earth.
Clean energy: It produces zero greenhouse gas emissions. It also requires less land than renewable energy technologies.
On-demand energy.

But for scientists to keep working towards a nuclear fusion future where these benefits come to life, they need funding. To get funding, there has to be excitement and interest surrounding the technology. This is why you see so many headlines that promise nuclear fusion is just around the corner. These headlines are supposed to make you feel excited at the prospect and keep the conversation on nuclear fusion thriving.

Just because we don’t have nuclear fusion ready to go tomorrow, doesn’t mean that progress isn’t happening. We don’t have viable nuclear fusion technology today, but we are closer to it than we ever have been. By working collaboratively, scientists around the world have managed to increase the performance of the plasma by a factor of 10,000. We’re also around a factor of 10 away from having the core of a fusion power plant.