We spend a lot of time writing about the impact of global warming, from mitigating the risks of climate change to accelerating decarbonisation and renewable energy adoption. And if I’ve learnt one thing, it’s that if the world doesn’t speed up its decarbonisation efforts, humanity could be facing a desolate future.
Solar and wind power are both brilliant steps in the right direction, but when there’s no wind and the sun isn’t shining, we can’t use them to produce electricity. So, what are the alternatives?
Imagine if there was a way to power the world that was clean, carbon free, and possible whatever the weather.
The answer could be written in the stars.
These giant balls of plasma generate an abundance of energy through a process known as nuclear fusion. But is it a process we could ever recreate on earth?
We already have nuclear energy. So what is fusion?
Today, nuclear power plants use a process called nuclear fission to produce energy.
Nuclear fission uses unstable atomic isotopes (like uranium 235) and harnesses the energy they create as they decay. It’s highly efficient and doesn’t generate carbon dioxide. However, fission does create some pretty nasty waste products that can stay radioactive for millions of years.
Typically, power plants use geological disposal to handle this waste – burying radioactive material deep underground so thick layers of rock can stop radiation reaching the earth’s surface.
But if that doesn’t happen because of disaster or meltdown, it can be utterly devastating.
Instead of using elemental decay, nuclear fusion combines two isotopes of hydrogen: deuterium and tritium (which are abundant in water and lithium). This creates an atom of helium, a lone neutron, and a lot of energy.
In fact, fusion can generate nearly 4 million times more energy per kilogram of fuel than oil or coal, with no carbon emissions at all. There’s also no long-term radioactivity; only the beta-emitting ingredient tritium, which has a short half-life of just over 12 years. And there’s no risk of meltdowns, as fusion reactions can’t sustain themselves outside of a reactor.
It’s a lot safer than fission. But it’s also far more difficult to achieve.
Major developments are paving the way for fusion on earth
To make fusion reactions happen, scientists need to overcome deuterium and tritium’s natural electromagnetic repulsion. For that, they need to create a huge amount of heat and pressure.
Currently scientists are looking at two key methods to achieve this: magnets and lasers. And recently there have been major breakthroughs in both.
South Korea’s electromagnetic tokamak
South Korea’s “Artificial Sun” is a type of fusion reactor called a tokamak. It’s a donut shaped device that uses magnetic coils to create the intense conditions needed for nuclear fusion. These magnets produce a twisted magnetic field, causing deuterium and tritium atoms to collide and creating energy that heats the walls of the reactor. This heat can then convert water to steam which powers turbines and generates usable electricity.
In 2022, the Artificial Sun sustained a temperature of 100 million degrees Celsius for 30 seconds, and the team are aiming for 5 minutes by the end of 2026. It’s an unimaginable temperature. To put it into context, the centre of the Sun is only a puny 15 million degrees Celsius.
The lasers of America’s National Ignition Facility
In the US, the Lawrence Livermore National Laboratory has used lasers to achieve the first ever net energy gain from nuclear fusion. Physicists fired 192 lasers at a target chamber containing deuterium and tritium, causing a huge implosion of energy that forced the atoms to fuse and release energy.
To be useful to humanity, the energy produced needs to be greater than the energy put in. And the US team has now achieved this not just once, but four times.
Nuclear fusion could be the future of clean energy
Nuclear energy is gaining traction worldwide. It was formally specified as one of the solutions to climate change in the COP28 agreement, and many governments are now pledging more funding for nuclear research.
Current fusion science is a far cry from the cold fusion controversies of the 20th century, and every new development gets us closer to achieving a clean, carbon-free, and near-infinite energy source.
I’m fortunate enough to get to write about electrification and renewable energy in my work at Radix, and it’s so exciting to think that one day – albeit in a few decades – I might be writing about fusion energy in the same way.
If you’re a bit of a physics geek like me, and curious to learn more about nuclear fusion, the International Atomic Energy Agency is a great place to start.
