Transcriber: Michael Nystrom Reviewer: Anna Sobota
My name is Matt Houde.
I’m a geologist, engineer, and co-founder at Quaise Energy.
At Quaise, we are looking to blast holes with microwaves
to drill the deepest holes on Earth.
And no, I’m not just quoting a plot device from Star Trek.
This technology is real. It’s been proven in the lab.
And I’m here to talk about why it is the key to unlocking
the largest untapped source of clean energy: geothermal.
Geothermal represents the heat in our ground.
The total energy content of which exceeds our global annual energy demand
by a factor of a billion.
Just tapping into a fraction of a percent of this energy
is more than enough to meet our energy needs for the foreseeable future.
In addition, geothermal is the ideal complementary resource
to wind and solar flows.
Not only is it a baseload resource,
it’s available 24/7 and is able to balance the intermittent flows
of wind and sunlight.
It also has a minimal land and material intensity
and is able to take advantage
of the largest workforce on the Earth today,
the oil and gas workforce,
present over 100 countries with 11 million jobs in the U.S. alone.
With the same skill set as that workforce,
we can rapidly scale geothermal to meet all of our energy needs by 2050.
Now, geothermal power production has been around for over 100 years
since the first plant came online in Tuscany, Italy.
And yet, as it stands today,
there’s only about 14 gigawatts of geothermal capacity
installed worldwide.
The reason for this is that access is constrained to niche locations
where you have a high geothermal gradient
and the ground is relatively hot at shallow depths,
places like the Ring of Fire or Iceland.
If we want to reach economic temperatures for geothermal everywhere,
the truth is it is universally accessible.
We just have to drill deep enough.
By drilling to 10 miles underground,
we can hit economic temperatures exceeding 300 degrees Fahrenheit.
Going even deeper,
we can get to temperatures exceeding 700 degrees Fahrenheit,
where water becomes supercritical,
the boundary between liquid and gas disappears.
And what this results in is a massive improvement in energy density per well.
That ten-mile distance I just quoted is just 0.2% of the distance
to the center of the Earth.
So, we’re not talking about a Jules Verne-like odyssey
to the Lost World.
This is actually not even pricking the skin of a grape
when it comes to the total depth of the crust.
So the challenge is, how do we access this energy?
Well, we have to overcome limitations in geothermal drilling.
Most geothermal fields today don’t drill deeper than three miles.
And the reason for that is that costs get exponential with depth.
Not only does the rate of penetration decrease
as you go into this harder rock that’s present in the deep basement rock,
but you also have increased non-productive time
due to equipment failures from the high temperature.
To provide an example,
the deepest hole drilled so far is the Kola Borehole in the Soviet Union.
It was started in 1970, and it took them 20 years to get down to about 7.6 miles
before the equipment began to fail due to those high temperatures.
And the truth is, if we want to scale geothermal to a terawatt scale,
we need hundreds, if not thousands,
of Kola Boreholes worldwide coming online every year.
The solution is to replace mechanical drilling methods
with an energy-matter interaction,
which is what millimeter wave drilling entails.
The process used to destroy that rock is called dielectric heating,
which is familiar to all of you here today because this is the same process
that your microwave oven uses to heat your food.
We generate microwaves at the surface
and transmit them down a hole through a metallic pipe
called a waveguide.
When that energy hits the rock,
it rapidly heats up the rock that actually vaporizes.
And when the rock condenses back into a fine ash,
we can flush that ash up-hole by a circulating purge gas
in a process virtually identical to air drilling today.
The key gating technology here is a gyrotron,
a device developed for fusion research
to heat plasmas to millions of degrees Celsius,
where in contrast, we only need to heat rock just over 3,000 degrees Celsius
for vaporization to take place.
Finally, our process is not only drilling a hole through the rock,
it's actually melting an outer ring around this hole, as you see here,
that, upon cooling, vitrifies to form a solid glass liner
that can not only keep the borehole stable while the drilling continues
but also prevents fluid inflows from coming into the hole
and interfering with the drilling process.
Now, millimeter wave drilling is an ideal solution for deep geothermal access
because the process acts independent of depth.
It’s not affected by the temperature
because there are no downhole tools besides the waveguide.
And in addition, dielectric heating mostly operates independent
of the pressures and temperatures of the Earth.
As well, millimeter wave drilling is optimized for the kinds of rock
we see in the deep continental basement,
the hard crystalline granites you might see at Yosemite
that conventional drilling struggles with.
However, millimeter wave drilling is not an ideal solution
for all rock types.
In particular, it’s relatively inefficient in softer soils, sedimentary rocks,
and porous rocks that may contain deposits of groundwater, oil, and gas.
Conveniently,
these are the same formations
that conventional drilling does best today,
so we ultimately propose a hybrid solution
that starts at the surface with conventional drilling
and continues until you hit that basement contact,
at which point you switch over to millimeter wave drilling
and continue to the ultimate depth target.
Now, so far today,
the millimeter wave drilling process was invented a little over a decade ago
at the MIT Plasma Science Fusion Center by Paul Woskov.
Millimeter wave drilling so far has been shown at MIT in the lab
with the low-powered gyrotron drilling the small holes you see here.
And currently, we’re in the midst of another experimental campaign
that is continuing to scale up these MIT results by a factor of 10
when it comes to the beam power of these microwaves,
as well as the depth of the hole that we are drilling.
Now, in parallel, we are also developing
the first field-deployable millimeter-wave drilling rigs.
As you can see here, we are integrating
the millimeter wave technology with conventional rig architecture,
whether it’s a mobile, smaller field-deployable rig
or the full-scale geothermal rig
that’s needed for drilling these deep boreholes.
These rigs will be ready to go online in the next two years
so that we can mobilize in the field once lab experiments are complete
for the next stage of drilling demonstrations going deeper and deeper,
while we can also begin the first commercial geothermal projects
in more shallow settings.
Now, there are still challenges that need to be addressed.
Chief among them, we have challenges related to fundamental science,
understanding the rock’s thermal properties and this vaporization regime,
as well as understanding how the rock and the rock vapor interact
with the millimeter wave beam in this environment.
We also have a challenge of scaling up the supply chain -
supply chain that currently is optimized
for one-offs, specialized projects, and fusion research,
and transitioning that supply chain over to one
that produces gyrotrons and high-power waveguide equipment
in the quantity of hundreds per year,
while also producing equipment that is robust and reliable
in the rugged field environment.
Finally, there are still challenges to address when we get to the field
and start drilling deep boreholes,
such as ensuring that we can remove
the full volume of ash that’s coming up this hole,
as well as maintaining a stable borehole at these great depths.
Now, the planet’s been around here for four and a half billion years
involving mountain-building vents, ice ages, and volcanic eruptions
that create the natural landscape
that we are quite literally sitting on today.
We all share this common ground.
Let’s make the most of it for a sustainable future.
(Applause)