This video is brought to you by Surfshark. Geothermal energy has the potential to be
an always-on power source for countries around the world.
However, it hasn’t been the hottest renewable energy option because drilling deep enough into
the earth to reach sufficiently high temperatures is difficult and costly. Yet, a startup has
recently unearthed a solution that might solve this problem: A heat ray to melt rocks (sort of).
I know it sounds like a Star Wars remake, but we’re not talking about the Death Star here.
This is actually a well-established nuclear fusion technology being reapplied to geothermal energy.
Could it unlock the true potential of geothermal energy and make it better than solar and wind?
Let’s see if we can come to a decision on this. Spoiler: it’s pretty cool … or should I say hot?
I’m Matt Ferrell … welcome to Undecided.
I’m currently in the process of building a new net zero home and am scoping out
getting a geothermal heating and cooling system installed for it.
The idea of tapping into the earth as a stable heat source for a heat pump system
is really enticing for our homes, but we can also tap deeper into the earth for a consistent
super hot heat source to power turbines to generate electricity for our cities and towns.
Unlike solar and wind, geothermal energy could provide a more stable supply of clean
power while taking up barely any land. On the other hand, current drilling techniques can’t
affordably reach the hottest spots of the Earth to unlock that potential. In fact,
penetrating deep into hard rock is a tricky and expensive process. Along with exploration,
digging wells accounts for 40% of the total upfront cost of a geothermal plant. That’s
why scientists are turning to a death ray … again, not really … I’ll get to this killer
technology in a minute, but first let’s have a brief recap on geothermal energy.
This source of power has been on our planet for ever. Well, actually inside it. The Earth’s inner
core is about as hot as the sun, which is why it’s often nicknamed, “the sun beneath our feet”.
Good news is that it will take billions of years for the Earth to cool down.
Fueled by residual heat from our planet’s creation and the decay of radioactive elements,
this underground sun gave rise to natural hydrothermal reservoirs.
Basically, the Earth’s nucleus heat pushes water up through permeable rocks until it hits a wall,
a.k.a. impermeable caprock. Trapped, the water pressure rises and can sometimes break through.
Think of Roman baths relying on hot springs. Or perhaps Icelanders toasting bread over geysers.
Aside from enabling carbon-free hot baths and outdoor barbecues we can use subsurface hot steam
to drive a turbine and produce electricity. To do that, you have different plant configurations.
Out of all options, binary cycle power plants are the newest and most sustainable ones.
Unlike other designs, binary plants don’t use the underground hot water to generate steam.
To be more specific, after extracting it and further heating it up to max 400°F (ca.
204 C), they run it through a heat exchanger. Here, the geothermal water transfers its heat
to a secondary liquid with a much lower boiling point. This then generates the steam that will
spin the turbine. The plant includes a condenser to convert steam back into a liquid and reuse it.
Leveraging this closed-loop binary system, you won’t boil off the geothermal fluids which, other
than water vapor, contain carbon dioxide, hydrogen sulfide and other toxic compounds. You can
probably see why this is a greener and preferred alternative to dry and flash steam plants.
The overall geothermal potential is huge. According to AltaRock Energy, harvesting only 0.1%
of the planet’s heat could satisfy the world’s energy hunger for 2 million years. Given how
cool that is (or hot), why did geothermal energy account for only 0.55% of our global electricity
generation as of 2018? Mainly because the accessible part of that heat is scattered across
the Earth’s crust. In fact, most hydrothermal reservoirs such as volcano fumaroles, springs
and geysers are only found along tectonic plates. In addition, the water filling shallow geothermal
pockets isn’t hot enough to make energy harvesting cost-effective. Not to mention the technical and
economic hurdles of reaching hotter spots using current drilling technologies. Yet,
thanks to a fusion-inspired drilling technology, the true potential of geothermal power could be
closer than ever. This innovation could get us below 10 km (ca. 6 miles) in a more cost-effective
fashion. Down there, geothermal sources have much higher temperatures and are more widespread.
While being cost-effective, the potential of solar and wind farms is undermined by their
intermittency. Instead, a 24/7 green energy source like geothermal could give us an extra
powerful weapon against global warming. Speaking of weapons, let’s dig deeper into how death rays
(again, not a real death ray) could push geothermal energy to a new level.
But before I get to that, I’d like to thank today’s sponsor, Surfshark. I always recommend
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Link is in the description below. Thanks to Surfshark and to all of you for supporting
the channel. Now back to the fusion tech that could push geothermal energy to a new level.
It all began with the work of Paul Woskov, a senior research engineer at MIT’s Plasma
Science and Fusion Center (PSFC). In 2012, he demonstrated the application of a gyrotron to
vaporize rock instead of grinding it. This high-powered vacuum tube generates a beam
of millimeter-long radio-frequency (RF) waves, which have been used to heat up the plasma and
control its temperature in fusion reactors for the last 50 years. Hijacking this fusion tech,
Woskov envisioned drilling ultra-deep geothermal boreholes. So, how does that work? You would
have a metallic tube embedding the gyrotron blasting high-frequency electromagnetic waves
to fuse the underground rock. The system injects a gas for cleaning up the post-vaporization mess.
To be more specific, the gas cools down the hot vapors, which condense into nanoparticles.
These are then flushed out of the well by the high-pressure stream, but you wouldn’t use this
sophisticated drilling for the entire process. I reached out to Quaise’s CEO, Carlos Araque, the
on-the-ground…or perhaps underground…arm of this geothermal revolution, who filled me in on that.
> “So in geology you have the sedimentary rock and then below it, you have the basement. Sedimentary
rock it's unconsolidated, it's easy to drill through. And it's what mechanical drilling systems
are very good at doing, so you drill that first portion conventionally, no difference there. But
the second portion is very hard to do. So, in that second portion we use a millimeter wave drill.”
Based on his experimental results, Woskov figured out that millimetric waves would make the drilling
process more cost-efficient. First, you wouldn’t be limited by temperature and rock hardness. On
top of that, there’s no need to have downhole mechanical equipment that could get damaged.
Thanks to a wavelength about 1,000x longer than that of a typical infrared laser,
the millimetric waves sputtered by the gyrotron
go through the incoming rock nanoparticles without experiencing significant scattering.
Which means the beam doesn’t lose much energy before reaching the target surface.
Also, the hot molten rock takes up way more energy when irradiated by a gyrotron compared
to when hit by a standard laser. Overall gyrotrons are up to 5x more energy efficient than the best
lower-wavelength laser you can get. But what about costs? Paul Woskov had some thoughts on that.
> “I did look at the cost of electricity to vaporize a volume of rock. That's the
main consumable in direct energy drilling. I made estimates that for an eight inch diameter hole and
about 10 kilometers deep, it would cost something like a half a million dollars of electricity
to vaporize an equivalent volume of granite of that size and depth. When you look at those
depths, the total cost of a mechanical drill well is somewhere in the order of $30 million.”
That’s crazy, right? If that proves out, we’re talking about saving tens of millions of dollars.
But there’s another key economic benefit of using heat rays. When relying on mechanical
processes such as rotary technology, you need a high-density fluid, a.k.a. drilling mud,
to counter the surrounding pressure on the well and prevent it from collapsing. In contrast,
millimetric waves don’t require drilling mud, but how would a gyrotron-drilled hole bear thousands
of atmospheres worth of pressure without failing? When coming out of the gyrotron,
some of the waves will hit the hole walls and create a glassy coating. Apart from sealing any
wall cracks, the heating process will increase the internal pressure, which balances the outer
force. As a result, it will be possible to burrow deeper yet more stable boreholes without adding
any drilling mud, which is another aspect that could make the whole process more profitable.
> “You're making a glass lined hole and that glass is very strong. And so in effect, we are casing at
the same time that we're drilling the hole, which is another big expense savings for making a hole.”
When factoring in all these extra costs,
Woskov’s brainchild turns out to be way more cost-effective.
> “I estimate that it could be maybe 10 times cheaper than a really deep mechanical drill wall.”
Aside from being costly, drilling mud doesn’t work at temperatures like 500°C (932 °F),
which is where geothermal energy production is most efficient.
Paul had some really nice insights on that.
> “Drilling muds don't function at those temperatures very well. The weight of the
column begins to run out the deeper you go because the density of the mud is never
close enough to the rock density. So eventually you can't have enough drilling mud columns
balancing the outward pressure. However, with direct energy drilling in high temperatures,
we are always over pressured, no matter what depth.”
To be more specific, this mud-free drilling system could profitably withstand
pressure-related stresses below 10 km, which is where geothermal access becomes universal.
According to the US Department of Energy (DOE)’s GeoVision report, leveraging these
untapped subterranean heat sources could increase geothermal-based electricity 26-fold by 2050.
In addition to a wider availability, when you go below 10 km (ca. 6 miles), you’ll find the
so-called Super Hot Rock (SHR) geothermal resources, with temperatures above 375°C
(707 °F). Under these conditions a geothermal plant can tap into supercritical water, which
is more energy dense than its non-supercritical counterpart. A well plunging into SHR would
yield up to 10x more energy than a conventional enhanced geothermal system (EGS). Based on the
technical and economic feasibility study conducted by AltaRock Energy on the Newberry Volcano site,
SHR would reduce geothermal’s Levelized Cost of Electricity (LCOE) by 50%. On top of that, the
company estimated that SHR-based geothermal could have a lower LCOE than onshore wind or even solar.
## Bringing geothermal energy to the lower level
Clearly, Woskov’s design holds promise for bringing our geothermal power supply to a
higher level (or lower depth I guess), which means our energy grid would become much less reliant on
fossil fuels. His fusion-inspired drilling tech is not just confined to the lab space.
Last February, an MIT spin-off, Quaise, raised $40M to develop this ground-breaking tech.
They graduated from using a 10-kilowatt gyrotron to drill a 10-centimeter-deep
hole in palm-sized stone to using Oak Ridge lab’s megawatt-sized gyrotron.
The company bore 3-foot-deep holes into much larger rocks. Quaise is partnering
with AltaRock to create their first pilot project where they’re aiming to drill a
3,300-foot-deep hole near the Newberry Volcano, which was chosen as an ideal testing site.
In fact, AltaRock believes this crater could be one of the largest unused geothermal resources
in North America. The presence of a shallow magma body makes the rock down there much hotter than
other places, which is why AltaRock could reach super hot temperatures (above 400°C or 752 F)
at a quarter the depth you would need to dig down to in other places. It’s a good testing ground.
Looking ahead, Quaise is planning to build its first full-scale hybrid drilling rig in 2024.
Based on this setup, Quaise would first use conventional rotary drilling to go
down to the basement rock, which is where they would activate their gyrotron-powered
rock-vaporizing system to reach 20 km (ca. 12 miles) to reach temperatures as high as 500°C
(932 °F). The company touts that they could get down to that depth in 100 days using a
1-MW gyrotron. Just to give you a sense of scale, the Kola Superdeep Borehole,
the deepest hole ever dug on Earth, went down to 40,230 foot-deep (12.2 km) and took 20 years to
complete. I can hear you already. Is 100 days even possible? Carlos shed some light on this.
> “When you're five kilometers down in a 10 day window, you may spend 30 hours drilling,
that's the life of the drill bit before it needs replacement.”
> “10 days is 240 hours, so you spend seven eighths of the time running the pipe in and
out of the hole to replace that drill bit. 10 days is a million dollars of break time.
We don't talk about drilling a hundred meters per hour, we talk about drilling a very consistent
five meters per hour. It just goes because there's nothing to replace.”
> > “Now, if we can
hit a drilling cost of a thousand dollars per meter regardless of depth, your LCOs are in the
1 to 3 cents per kilowatt hour, so cost parity with wind and solar, but firm, and always on.”
So, in theory, it sounds like Quaise has got some chances to achieve their goal.
In practice, we should wait for real-world tests in the field. Nevertheless, the company
has a clear and clever long-term vision. They aim to retrofit existing fossil fuel plants
which will eventually be decommissioned during the low-carbon transition. Making the most out
of this ready-to-use infrastructure, they could simply swap coal or natural gas generated steam
with round-the-clock underground hot vapor to spin the turbines.
> “Steam can come from the ground, so that idea
gets a lot of traction with power project developers, because they have these power plants
that they're losing their social license to operate and they're increasingly less in the
money, so there's very few alternatives for these power plants to continue to operate. Those are
the people that are most interested in what we're trying to propose and trying a pilot with them.”
A pilot plant sounds exciting,
but looks like it’ll still take some time for it to…pick up steam…
> “We're still more than three, four years away because we still need to do
the technology demonstration before we even get to that.”
Along their geothermal drilling path Quaise may encounter some other issues.
The deeper you excavate, the more energy you lose. As it stands, making up for this power
loss means stealing electricity from the grid or running diesel generators. On the other hand,
Quaise’s CEO claims that fossil fuels consumed by their drilling system would be less than 1%
of the renewable energy generated by their well over its lifetime.
But their system needs to account for gas pressure losses too. That’s because of the friction between
the gas and the pipe walls. The further down the gas travels, the higher its pressure drop,
the bigger the pump you need to circulate it in and out of the well. That’s one of the reasons why
Quaise estimated that 20 km may be the lowest depth they could get to. Another drawback of
ultra-deep digging might be earthquakes. Creating wells could destabilize geological layers,
which can trigger seismic activity. This has cooled down some geothermal enthusiasts in
different countries after power plants were forced to close. Carlos had a different take on this.
> “When you drill for geothermal today, you're mostly drilling near tectonic boundaries because
that's where the heat is closest to the surface, so you are very intentionally drilling near
problematic zones with very young and unstable geology.
When you have the luxury to go deeper without an exponential increasing cost,
you move away from those instabilities. I would even argue that maybe 95% of the business case for
our drilling is away from tectonic boundaries. We're actually trying to make geothermal
available no matter where you are. And most of the world is actually not on a tectonic boundary.”
> Earthquakes aside,
Quaise will need to keep an eye on budget. As reported by the International Renewable Energy
Agency (IRENA) in 2019, setting up a geothermal plant would cost nearly $4,000/kW. Which is
roughly 4x more than what you need to spend for installing a solar farm. However, as mentioned by
Carlos and Paul earlier, gyrotron-powered drilling could save money compared to a mechanical process.
I don’t know if Quaise’s geothermal approach is the panacea for our energy transition,
but it should definitely be thrown into the mix. Relying on multiple clean electricity sources
is the sustainable way forward. Carlos’ view seems to align with mine on this.
> “When I think of renewables, they're trying to do more with much, much more,
so I don't think that's sustainable. And I think everybody forgets that, right?
I'm not saying we shouldn't do renewables, I think we should, but we should not forget that
things like this and things like fusion, they need work
because they are the ones that can actually get us to where we need to be as a species.”
I’m really excited by the potential of this. It’s also really cool to see a technology from
fusion research getting reapplied in such a unique way. The development of fusion-inspired
drilling would let us tap into plenty of super hot fluids by overcoming geographical
and geological limitations. It could unleash a perpetual spring of geothermal power for a
zero-carbon energy-independent world. However, although heat rays are based on solid tech,
there are still economic barriers and testing to go through before reaching an industrial scale.
So are you still undecided? Do you think this could make geothermal energy the future
of our energy grid? Jump into the comments and let me know. If you liked this video,
be sure to check out one of these videos over here. And thanks to all of my patrons for your
continued support. And thanks to all of you for watching. I’ll see you in the next one.