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from
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Monty Rakusen/Getty or a pipe dream, fusion is suddenly making enormous leaps...
He wrote a term paper on how scientists were trying to harness fusion (the physical effect that fuels the stars) in wondrously efficient power plants on Earth.
This is the ultimate clean-energy dream. It would provide massive amounts of clean electricity, with no greenhouse gases or air pollution.
It would do it on a constant basis, unlike solar and wind. Whatever waste it created would be easily manageable, unlike today's nuclear power plants. And fuel would be limitless.
One of the main
ingredients needed for fusion is abundant in water. Just one little
gram of hydrogen fuel for a fusion reactor would provide as much
power as 10 tons of coal.
That comment, Whyte says with a hearty laugh,
Indeed, over the next few decades, as Whyte mastered the finicky physics that fusion power would require and became a professor at MIT, the concept seemingly got no closer to becoming reality.
It's not that the science was shaky:
Researchers, like Whyte, knew all too well the sardonic joke about their work:
That line took on an especially bitter edge one day in 2012, when the U.S. Department of Energy announced it would eliminate funding for MIT's experimental fusion reactor.
Whyte was angry about the suddenness of the news.
But above all, he was dismayed.
Global 'warming' was bearing down year after year, yet this idea that could save civilization was losing what little momentum it had.
in Germany, 2017.
Photo:
Picture Alliance/Getty
He looked for other things to focus on,
As it turned out, Whyte never really walked away.
Instead, he and his colleagues and graduate students at MIT's Plasma Science and Fusion Center figured out a new angle.
And last winter, MIT declared that Whyte's lab had a fundamentally new approach to fusion and threw its weight behind their plan with an unusually public bet, spinning out a company to capitalize on it.
An Italian oil company and private investors - including a firm funded by Bill Gates and Jeff Bezos - put at least $75 million into the company, known as Commonwealth Fusion Systems (CFS).
The startup intends to
demonstrate the workings of fusion power by 2025.
Real, live, economically viable power plants could then follow in the 2030s. No joke.
When I ask Whyte, who is 54, to compare his level of optimism now to any other point in his career, he says, simply:
But it's not just MIT.
At least 10 other startups also are trying new approaches to fusion power. All of them contend that it's no longer a tantalizingly tricky science experiment, and is becoming a matter of engineering.
If even just one of these ventures can pull it off, the energy source of the future is closer than it seems.
Imagine that I told you I was developing a special machine.
If I put power into it, I
could get 10 times as much out. Because of the undeniable laws of
physics, I could show you on paper exactly why it should be a
cost-effective source of vast amounts of electricity.
Until I perfected that design, my machine would use up more power than it produced.
And I couldn't get close
to perfecting the design without spending years and years building
expensive test machines that would reveal problems that I would try
to address in subsequent versions.
Instead they fuse,
sparking a reaction that transforms the hydrogen into helium and
releases cosmic amounts of energy in the process.
To generate that effect inside a fusion reactor, ionized gas - which is called plasma - must be heated and compressed by man-made forces, such as an ultra-powerful magnetic field.
But whatever the method, there's just one main goal. If you get enough plasma to stay hot enough for long enough, then you can trigger so much fusion inside it that a huge multiplier effect is unlocked.
At that point, the energy
that is released helps keep the plasma hot, extending the reaction.
And there still is plenty of energy left over to turn into
electricity.
Ever since the 1950s, scientists have used spherical or doughnut-shaped machines called tokamaks, including the one at MIT that lost funding a few years ago, to create fusion reactions in plasmas bottled up by magnetic fields.
But no one has done it
long enough - while also getting it hot enough and dense enough -
to really tip the balance and get it going. Heating the plasma and
squeezing it in place still takes more energy than you can harvest
from it.
ITER, a mega-billion-dollar reactor being built in France by an international consortium, is designed to do it and finally prove the concept. But ITER - which is also way behind schedule and over budget - overcomes the limitations of previous tokamaks by being enormous.
It's the size of 60
soccer fields, which probably isn't an economical setup for
power plants that the world will need by the tens of thousands.
ITER (International Thermonuclear Experimental Reactor) under construction.
Photo: Christophe Simon/Getty
That is what motivates all the fusion startups. Several have decided the answer is to use something other than a tokamak and its circular coils of magnets. They're updating old designs, including hitting plasma with lasers, or cooking up new ones, such as compressing it with something like a particle accelerator.
One startup plans to push
on the material with pistons.
As Whyte saw it, why try to invent something totally new when you could take advantage of all those decades and billions spent researching tokamaks?
Instead, they would
rethink the design to make tokamaks modular and much cheaper and
weave in brand-new materials that can induce and confine a fusion
reaction.
And then they dug in...
MIT's tokamak, which still sits in a two-story tall, garage-like room in a former Nabisco cookie warehouse, generated a magnetic field by running electricity through copper coils that surrounded a round metal chamber.
In that chamber, plasma would be heated with microwaves and other methods to millions of degrees.
On one of its last runs,
it set a new record for plasma pressure while hitting 35 million
Celsius.
Particle accelerator.
Photo: Monty Rakusen/Getty
A superconductor conducts
electricity so well that it doesn't build up electrical resistance
and this new tape maintains that property, even at slightly higher
temperatures than other superconductors do.
As they plotted out ways of winding the tape into coils in a tokamak, they realized this method could double the strength of the magnetic field they could exert on a plasma.
Increasing the field
strength is crucial because plasma is wild. It's unstable and
evasive, and only overwhelming force can keep it from spreading out
and cooling too much.
That led them to another problem with traditional tokamaks.
That's unacceptable for a power plant in regular use. And again, one of Whyte's graduate students had a great idea.
If you apply the superconducting tape in sections, with joints, the magnets can be snapped on and off for quick and easy repairs or upgrades.
Other big ideas kept coming.
One of the great things about fusion is its inherent safety. It's impossible for this tiny star to slip out and cause trouble, because the plasma's weird physical state can't be sustained outside of the magnetic field.
Still, the plasma does
send something out that you've got to deal with: neutrons.
Deuterium is readily available in seawater, but tritium is very rare, so you have to make it. (More on that in a minute.)
In this version of
fusion, 80 percent of the energy that is released comes out in the
form of neutrons. These are subatomic particles that have no
electric charge, so they're not contained by the magnetic field.
They come flying out like angry spittle.
What to do about that in
a power plant that needs to run for long stretches?
In essence, the MIT plan takes a ride on the neutrons by catching them in a liquid.
Neutrons wreck solid materials by scrambling the order of their atoms, but liquids are already disordered, by definition.
In the design that CFS is developing, the neutrons pass through an inch or two of steel and then barrel into a liquefied salt, which they essentially just heat up. Then, that molten salt can be pumped around a power station to generate electricity.
By the way, there's lithium in the molten salt, and when neutrons hit lithium, they create tritium, which you can take out and use to fuel the fusion reactor.
designed to study the ionization and compression produced in deuterium plasma, 1964.
Photo:
Fox Photos/Getty
Blanketing the tokamak's steel wall with molten salt will lessen, but not eliminate, the damage that the neutrons would otherwise cause to the metal. It will have to be replaced every so often.
Just how often? That's a
crucial question for the cost of a power plant.
That looks doable;
reducing the erosion of the wall in fusion reactors is a
long-standing field of research.
There will be lithium in
that liquid, too, to breed tritium.
Is that a big problem?
Well, one of the novel things about a fusion company called TAE Technologies, which has raised $600 million from Google, the late Microsoft founder Paul Allen, and other luminaries, is that it plans to fuse hydrogen protons with boron, a reasonably abundant element, because that reaction emits hardly any neutrons.
TAE's co-founder and CEO, Michl Binderbauer, says that because of its cleaner profile, hydrogen-boron fusion is,
But since we're talking about fusion, of course there's a catch.
Hydrogen-boron fusion is much harder to pull off:
And the "reaction rate" is much lower, which means less fusion happens.
TAE is going to start with deuterium-tritium fusion before trying to work its way up. In the meantime, Whyte and just about everyone else in fusion thinks deuterium-tritium fusion is well worth gunning for.
Any radioactive components in MIT's design will be relatively small and have a short half-life. The material would be nowhere near as problematic as the stuff that comes out of nuclear power plants today.
If fusion plant operators have to replace the inner wall from the reactor Whyte envisions, they'd,
Before any of that
happens, CFS will try to pull off fusion's most elusive trick: doing
something ahead of schedule.
Then, it will need to raise hundreds of millions to build a prototype reactor, at a location to be determined. The company has said it intends to get that reactor running by 2025.
But its CEO, a former MIT
graduate student named Robert Mumgaard, says it could happen
even sooner.
When I asked for updates, I got some vague replies, ranging from,
If fusion power just won't work,
I got the most reassuring
answer from Christofer Mowry, CEO of
General Fusion.
Because so many companies are trying to make fusion power practical, and because demand for it will be so high,
At CFS, Mumgaard sees parallels with the story of human flight.
Before the Wright brothers finally got a plane off the ground, a lot of people tried and got kind of close. Plenty of observers assumed that meant human flight would always remain a fantasy.
But all that time, through all those failures with gliders and flapping man-made wings, engineers were systematically probing aerodynamics.
The Wright brothers built on that knowledge and combined it with insights about control mechanisms that they had from working with bicycles.
And only then, was it obvious: yes, humans can fly.
He refers to his
company's plan to build a prototype as the Kitty Hawk moment.
Then,
And it's hard to cheer him up on that point.
None of the existing carbon-free alternatives seem suited to the scale of the climate problem.
When I pose the same question to Whyte, I get a slightly different answer.
He sounds like a person who has considered what would happen if he gave up on this dream, and then renewed it instead.
And then he slaps his hand on the table in front of him for emphasis.
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