Thanks to Linode, a cloud computing company with award-winning customer service,  for supporting this episode of SciShow.

Head to linode.com/scishow to learn more and get a $100 60-day credit on a new Linode account. [♪ INTRO] On February 9th, scientists working  at the UK Atomic Energy Authority’s Joint European Torus facility in  Oxford made a pretty cool announcement. They announced that they had more than  doubled the previously held record for sustained nuclear fusion energy.

And what is really exciting is that,  in a few years, scientists will essentially get to repeat the same  experiment, but at a much larger scale. Which could finally put us on the road  to a powerful source of clean energy we’ve been pursuing for the  better part of a century. Nuclear fusion is a potential  source of energy scientists have been investigating since the ‘40’s and ‘50’s.

It is powerful and it is clean, low on  greenhouse gas emissions and other waste. Potentially, that is. The problem with fusion power so  far is that it’s never broken even.

We’ve been able to do it, but it always  took more energy to run the reaction than we actually got out of it. And the JET reaction didn’t change that. It simply couldn’t run long enough.

But it wasn’t necessarily meant to. That’s because this is a test  run for a larger experiment that is scheduled to happen fairly soon. Which makes this announcement an  incremental step, but an important one.

A hypothetical fusion plant would use heat  to boil water and spin steam turbines, just like a coal or nuclear  fission power plant does. But that heat would be generated by the same  forces that occur in the heart of the sun. Our sun fuses together atomic  nuclei to sustain itself.

Because of complicated physics stuff  related to how atomic nuclei stay stable, some portion of the total mass of  those two nuclei is transformed into an amount of energy following  Einstein’s famous E=mc squared equation. This is only possible under extreme  conditions because the nuclei, which contain protons, are  both positively charged. Like putting the north poles of two magnets  together, they naturally repel each other.

The only way to reliably overcome this  is by essentially brute-forcing it with super high temperatures and pressures. The sun, with a mass of roughly two  billion, billion, billion metric tons, has no problem putting on the pressure. On Earth, however, we cannot match that.

So, we can’t hit the pressure,  but, remarkably, we can go hotter. To do this, scientists use a device  called a tokamak, which is essentially a big, hollow, donut-shaped device  equipped with really powerful magnets. In this giant hollow donut, scientists  first suck the air out to create a vacuum, then inject the fusion material and hold  it in place with powerful magnetic fields.

This reactor, called JET for short, uses a mix of two specific isotopes of  hydrogen called deuterium and tritium. Isotopes are versions of elements  with a different number of neutrons. The most common version of  hydrogen just has one particle, a proton with no neutrons.

Deuterium has one proton and one neutron. Tritium has two neutrons and a proton. Scientists can technically  fuse other elements as well, but this mix is especially interesting,  since it releases more energy than most fusion reactions and can be  done at relatively low temperatures. “Relatively” being the important word here.

By bombarding the material using particle  accelerators, as well as electromagnetic waves in a process somewhat akin to  what you would find in a microwave oven, scientists can heat it up to 10 times what  we would find the center of the sun.   Now, even if the magnetic field failed,  the reaction would immediately fizzle out. So there’s no risk of a  meltdown with fusion energy. So that is how fusion works and how  it’s working in this particular reactor.

The latest test is mainly impressive  because of how much energy it yielded. The previous record was 22 megajoules  of heat energy, set way back in 1997. But the JET scientists announced  they got 59 megajoules, more than doubling the old record.

In this experiment, JET ran for five  seconds before its magnets got too hot. Now, we use time to measure energy output, so running the numbers we  get 11 megawatts of energy. Now, that is honestly not a ton of energy.

It’s about the same as the  energy a household uses in a day. And they didn’t even break even. It still took more energy to  run than they got out of it.

But this is just the little baby experiment. The big boss is just around the corner. JET is located in Oxford, England, but in  southern France, scientists are preparing the ITER, which is both larger  and more advanced than JET.

And while JET is likely to be decommissioned soon, ITER is scheduled to begin experiments in 2025. ITER is exciting because it has different  guts that would allow it to run longer. And scientists seem confident that if  they can get JET to run for five seconds, they can do it for longer at ITER.

Researchers estimate that if everything  works with the same with the bigger ITER, the reaction will more than break  even and actually produce net energy. Meaning, the breakthrough with  JET is the pre-breakthrough to actually making fusion viable. Hopefully, anyway.

And even if they do produce net energy, it’s  safe to say there’s still a lot to figure out. But this is exciting because if  we can get fusion energy to work, it represents a lot of energy. A ton of deuterium, fused with tritium, would produce as much energy  as 29 billion tons of coal.

And deuterium is relatively abundant  and can be harvested from ocean water. Tritium is harder to get, but  we can make it from lithium. And fusion would produce no greenhouse gases.

There would be small amounts of radioactive  waste, but they should be short-lived. Unfortunately, fusion almost certainly  is not going to happen soon enough to help us transition away from fossil fuels. We need to address the climate crisis  with current technology kind of now.

But fusion could be the way  we power things in the future. We will just have to wait and  see how things go with ITER! You just watched a person  talk to you over the internet.

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