This is the classic joke.
If anybody’s heard anything about
fusion, it’s the perfect energy
source that’s 30 years away and
will always be 30 years away.
Like, I hate that joke so much.
I hate it so much.
I’m dedicating my life to eliminating
that joke from the English language.
Welcome back to Today I Learned: Climate,
the podcast where you learn about climate
change from real scientists and experts.
I’m your host Laur Hesse Fisher, with the
MIT Environmental Solutions Initiative.
Today’s episode concludes our series
on energy and climate in partnership
with the MIT Energy Initiative.
Our guest is an expert on a technology
that could completely change our
global energy system -- but, so far,
hasn’t powered a single lightbulb.
My name is Dennis Whyte, a white with a Y.
um, and I'm a professor, uh, here at,
at MIT, and I'm also the director of the
plasma science and fusion center of MIT.
Professor Whyte studies fusion energy,
which is the process that our stars
use to generate so much heat and light.
Stars, by the way, and our own sun,
is just a big ball of hydrogen.
Most of the universe is hydrogen.
So hydrogen is the simplest and most
abundant element by far in the universe.
At the center of a sun and a star, it
becomes hot enough and there's enough
pressure that the hydrogen that wants
to stay hydrogen is forced to get
close enough to another hydrogen and
they fuse, and they produce helium.
And when that happens, it releases
staggering amounts of energy.
It's 20 to a hundred million times more
energy release per particle than you
can ever get out of a chemical reaction.
So you're saying that the kind of energy
that we can produce right now by burning
coal and burning natural gas is just
absolutely nothing like the kind of
energy that you can produce with fusion.
That's right.
What we’re after, is bringing the
power of the stars which is essentially
inexhaustible, down to earth, to mankind.
OK but if fusion normally
happens inside a star, what
does it look like here on Earth?
So what we, in the end we make is it
has, it's actually a rather modest
looking object that's got some
high tech inside of it, but what
we're making is a magnetic cage.
It looks like you have a big piece of
steel kind of, but it’s not that large.
It’s about the size of a coat closet.
So first thing that we do, we get
all the air out, we build a steel
chamber and we evacuate every particle.
This is basically a
vacuum, like outer space.
Then we put in a little
bit of the fuel, hydrogen.
But teeny, teeny amounts, And
then we zap it with some heat
and get it hot really quickly.
The challenge of fusion is that fusion
happens in one place, in the center of
stars, cause it's the one place that can
get hot enough to make fusion happen.
So at its heart it’s about getting
the fuel, the hydrogen hot enough.
How hot does it need to get?
Um, so the center of our sun
is about 15 million degrees...
Celsius.
Celsius?
Celsius.
Celsius.
Yeah.
And what is… I mean in Fahrenheit?
Oh I don’t, I’m a scien--, we
don’t, we never use Fahrenheit.
It’s about like 25 to
30 million Fahrenheit.
Sorry, I never think in fahrenheit.
So it turns out to make it work
on earth, it has to be at about
a hundred million degrees.
That's inconceivable.
Yes.
Most people just like sort of have
a, you know, a guffaw moment, blah.
Like what, what, how can that be possible?
We as humans have almost no intuition
about what something feels like at that,
because we can literally never touch it.
So we're used to thinking
of a temperature, right?
I mean, but over a pretty-
ice cold or lukewarm water.
You've touched an oven, it's really hot.
This is really an incredibly
small range of temperature.
Right, things can get a lot hotter
and a lot colder than what we
experience in our daily lives.
When you crank up the temperature
to thousands or millions of degrees,
something fascinating starts to happen.
Ice.
What happens when you heat it up?
It melts?
It becomes a liquid.
What happens if you then put that
liquid on your stove and get it hotter.
It becomes steam, it becomes a gas.
So turns out though, if you take
that gas and that steam and you
keep making it hotter, uh, actually
at about 5,000 degrees, something
really fundamental changes in matter.
It becomes a different
phase of matter again.
It becomes something called a plasma.
You might have seen pictures of plasma
on Earth -- lava, from volcanoes.
Lightning also, actually is plasma.
You may have also seen closeup
pictures of the surface of the
sun – the tumultuous surface and solar
flares are also examples of plasma.
And that’s what’s inside Prof.
Whyte’s fusion chamber.
Something at a hundred million
degrees sounds dangerous.But
it's actually the opposite.
It's because it's, um, to use a
technical term, it's so far out of
equilibrium with the rest of the earth,
blowing on it actually turns it off.
My breath is at room temperature and
there's more particles in my lungs
than there are in, in the fusion.
The listeners can't see this,
but you'll see where I'm doing.
Like I just, I like blowing
out like a birthday candle.
That would extinguish the fusion
immediately inside of this.
So it turns out that that's actually
the objective that we have achieved
quite routinely is a hundred million.
Right, actually getting the temperature
to 100 million degrees -- which is
still inconceivable to me -- isn’t
actually the biggest challenge
of producing energy from fusion.
It’s about getting all the conditions in
place to keep the fusion reactions going.
We need to supply heat
to actually get it hot.
So the equivalent is
thinking like of a match.
You put a bonfire
together, here's a match.
That's the initial source of heat.
Then the bonfire, it
lets itself keep going.
We've never made the bonfire.
Like we've lit the match.
We've gotten the wood hot, we
studied it, but it never took off.
And what that requires is actually
that you're making so much fusion
energy that is keeping itself hot
primarily, and you're making a lot
more energy from the fusion than the
heat that's required to make it hot.
Yeah, and that’s how stars work -- they
are made of hydrogen and are able to
keep fusing together hydrogen atoms
into helium, making a chain reaction of
fusions that’s able to sustain itself.
And so that’s the challenge here on
earth: keeping the chain reactions
running long enough so that it generates
more energy than we’re putting into it
to get it that hot in the first place.
But the prototype that Prof.
Whyte works with here at MIT is one of
the most advanced examples of fusion
energy on earth, and he thinks he’s
getting close to having this happen.
How does this look like
in the real world then?
If you just draw a box around the exotic
part it just looks like a heat source...
So then it, does it boil the water
and produce steam and turn a turbine?
Or what...
That's one of the things
you can do with it.
Um, that's actually, you know,
we think we can actually be
much more efficient than that.
Cause one of the features of fusion
is it can make like staggering what
we call very high quality heat.
We tend to keep thinking about
de-carbonization um, and the climate
crisis around making electricity.
Electricity is like, at most
a quarter of the problem.
Like decarbonizing long range
transportation, industrial heat
processing, refining fuels,
concrete, these things all
have intense heat requirements.
So what fusion has at its heart
is that it doesn't just plug into
the electrical infrastructure.
It plugs into our energy
infrastructure overall.
We’ve mostly focused on electricity
in this series, but if you’re making
concrete or steel, what you need
is a ton of raw heat, way more
than electricity could provide.
Right now, those kinds of factories
use fossil fuels for that intense
heat -- but fusion could deliver that.
Fusion power could also be dispatchable,
which means it could be turned
on and off exactly when we need
it, unlike other forms of clean
energy like wind and solar power.
It's an on demand energy source.
You can control the, the amount of
fuel in the, in the power output
on the timescales of like seconds.
You can turn it off in
a fraction of a second.
And then there’s the sheer amount
of energy fusion can deliver.
In fact, it’s so much energy that Prof.
Whyte actually sees it as one of the
challenges of getting the first fusion
power plant out in the real world.
One of its limitations is that
it has a minimum level of output
of power, to make the star work.
The minimum unit is probably like
50, a hundred million Watts of
power, which is a lot of power.
Like in the energy market
that powers like a small city.
So this, we'd have to build
it at an enormous scale to
get the very first one going.
This is why people are so excited
about the potential of fusion energy.
I don't think it's an exaggeration
to say that economic fusion
energy changes the world.
It changes humanity's relationship
to energy and how we use energy.
Because it can be deployed into
many of the present energy, energy
systems and infrastructures.
And it can be deployed anywhere on the
planet in principle because you don't
need the, you don't need particular
access to a particular kind of fuel.
All right, let’s come back
down to Earth for a second.
Affordable fusion energy doesn’t
exist yet, and even Prof.
Whyte can’t promise that it ever will.
So why spend so much
time talking about it?
Well, one of our main messages
in this energy series is that no
one energy source can get us to a
carbon-free energy system on its own.
We’ve heard scientists from all kinds
of backgrounds tell us that we need
many strategies together -- wind and
solar along with energy storage and new
power lines; energy efficiency; older
technologies like nuclear and young
ones like carbon capture and storage.
The potential of fusion shows us how much
we could gain from also making investments
in totally new energy technologies.
And it’s not just fusion--other growing
energy sources we haven’t had time
to dig into, like hydrogen power,
advanced biofuels, and concentrated
solar power, which is totally different
from the solar photovoltaics we covered
in our episode on wind and solar.
All of these could fill huge gaps in
our ability to decarbonize our whole
energy system, from electricity to
transportation to the heat needed to
make things like concrete and steel.
Decarbonizing our energy use
is probably the hardest thing
humanity will ever have to try.
Changing how you make and interact with
energy is at the heart of everything
that we do, it's our entire way of life.
We need all hands on deck on all of the
clean energy sources about getting there.
And I really want to make sure
fusion has a real fighting
chance of being one of those.
For more on fusion check out
the MIT Energy Initiative’s
podcast interview with Prof.
Whyte, where he speaks more about
commercializing fusion energy.
We’ll also have other resources
-- including an guide for educators to
use this podcast in the classroom -- on
our website, tilclimate.mit.edu
Thank you for tuning into Today I
Learned: Climate, brought to you by the
MIT Environmental Solutions Initiative.
This was our last official episode
in our second season, which
we produced in collaboration
with the MIT Energy Initiative.
I say that it’s our last official
episode, because we may have a bonus
episode -- or two -- up our sleeve.
Just a heads up.
We’re now preparing for season three, so
if there is a topic that you’d like us
to cover, send us a tweet @tilclimate,
or email us at tilclimate@mit.edu.
A shout out to our team, those who
worked with us on our first two seasons:
Our student production assistants,
Ruby Wincele, Cecilia Bolon, Darya
Guettler, Olivia Burek and Skyler Jones.
Our graduate student writers,
Jessie Hendricks and Rachel Fritts.
Aaron Krol, who did our show artwork
and is a contributing writer.
Blue Dot Sessions created our music
The fabulous David Lishansky,
our audio editor and producer.
I’m your host Laur Hesse Fisher.
I want to thank Prof.
Dennis Whyte -- and all our experts
for speaking with us for this
season -- and thank you for listening.
