The fundamental currency of our universe is energy.
It lights our homes, grows our food, powers our computers.
We can get it lots of ways:
Burning fossil fuels, splitting atoms,
or sunlight striking photovoltaics.
But there's a downside to everything
Fossil fuels are extremely toxic,
Nuclear waste is... well, nuclear waste,
And, there are not enough batteries to store sunlight for cloudy days yet.
And yet the sun seems to have virtually limitless free energy.
Is there a way we could build a sun on Earth?
Can we bottle a star?
The sun shines because of nuclear fusion.
In a nutshell, fusion is a thermonuclear process.
Meaning that the ingredients have to be incredibly hot.
So hot, that the atoms are stripped of their electrons
Making a plasma where nuclei and electrons bounce around freely.
Since nuclei are all positively charged,
They repel each other.
In order to overcome this repulsion,
The particles have to be going very, very fast
In this context, very fast means "very hot"
Millions of degrees
Stars cheat to reach these temperatures.
They are so massive, that the pressure in their cores
Generates the heat to squeeze the nuclei together
Until they merge and fuse
Creating heavier nuclei and releasing energy in the process.
It is this energy release that scientists hope to harness
In a new generation of power plant,
The fusion reactor.
On earth it's not feasible to use this brute force method to create fusion.
So if we wanted to build a reactor that generates energy from fusion,
We have to get clever.
To date, scientists have invented two ways of making plasmas hot enough to fuse:
The first type of reactor uses a magnetic field to
Squeeze a plasma in a doughnut shaped chamber
Where the reactions take place.
These magnetic confinement reactors
Such as the I.T.E.R. reactor in France,
Use superconducting electromagnets cooled with liquid helium
To within a few degrees of absolute zero.
Meaning that they host some of the biggest temperature gradients in the known universe.
The second type called "Inertial confinement"
Uses pulses from super-powered lasers
To heat the surface of a pellet of fuel
Imploding it, briefly making the fuel hot and dense enough to fuse.
In fact, one of the of the most powerful lasers in the world
Is used for fusion experiments
At the National Ignition Facility in the U.S.
These experiments and others like them around the world
are today, just experiments.
Scientists are still developing the technology,
And although they can achieve fusion,
Right now, it costs more energy to do the experiment
Then they produce in fusion.
The technology has a long way to go before it's commercially viable,
and maybe it never will be.
It might just be impossible to make a viable fusion reactor on earth,
But if it gets there, it will be so efficient
That a single glass of sea water, could be used to produce
as much energy as burning a barrel of oil, with no waste to speak of.
This is because fusion reactors would use hydrogen or helium as fuel
And sea water is loaded with hydrogen
But not just any hydrogen will do.
Specific isotopes with extra neutrons called Deuterium and Tritium
Are needed to make the right reactions.
Deuterium is stable and can be found in abundance in sea water,
Though Tritium is a bit trickier.
And there may only be 20 kilograms of it in the world
Mostly in nuclear warheads
Which makes it incredibly expensive.
So we made need another fusion buddy for Deuterium instead of Tritium.
Helium-3, an isotope of Helium, might be a great substitute.
Unfortunately, it's also incredibly rare on earth.
But here, the moon might have the answer.
Over billions of years, the solar wind may have built up huge deposits
Of Helium-3 on the moon.
Instead of making Helium-3, we can mine it.
If we could sift the lunar dust for helium,
We'd have enough fuel to power the entire world for thousands of years.
One more argument for establishing a moon base, if you weren't convinced already.
Ok, maybe you think building a mini sun
Still sound kind of dangerous
But they'd actually be much safer than most other types of powerplants
A fusion reactor is not like a nuclear plant,
Which can melt down catastrophically.
If the confinement failed, then the plasma would expand and cool,
And the reaction would stop.
Put simply, it's not a bomb.
The release of radioactive fuel, like Tritium,
Could pose a threat to the environment.
Tritium could bond with oxygen making radioactive water,
Which could be dangerous as it seeps into the environment.
Fortunately, there's no more than a few grams in use at a given time,
So a leak would be quickly diluted.
So we've just told you that theres nearly unlimited energy to be had
At no expense to the environment
In something as simple as water.
So, whats the catch?
Cost. We simply don't know if fusion power will ever be commercially viable.
Even if they work, they might be too expensive to ever build.
The main drawback, is that it's unproven technology
Its a 10 billion dollar gamble
And that money might be better spent on other clean energy
That's already proven itself.
Maybe we should cut out losses
Or maybe, when the payoff is unlimited clean energy for everyone,
It might be worth the risk.
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If you want to learn more about global energy,
Here's a playlist about nuclear energy, fracking and solar power.
Let us know in the comments if there are other technologies you want us to explain.