June 16, 2025 • 9 mins
Geothermal energy taps into the Earth’s natural heat to produce clean, reliable power—but why isn’t it more widespread? In this episode, we explore how geothermal works, where it’s being used effectively, and the barriers holding it back. From volcanic hotspots like Iceland to ambitious UK projects in Cornwall, we uncover the challenges and potential of this often-overlooked renewable.
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Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
(00:00):
Welcome to Ten Minute Climate, the podcastbrought to you by Beaverbrook Energy.
Join Max I am Max and Tony.
Hi, I'm Tony, who between themhave got over 70 years of experience
in the energy industryand they're here to share it with you.
Each episode they'll cut through myths,answer the questions you've always wanted
to ask, and break down the latest newsabout the energy transition.
(00:22):
It's everything you need to knowdelivered in just ten minutes.
So let's get started.
The thing. I'd been fascinated about thisfor a long time.
Journeys in the sense of the earth,wasn't going to work because it's 6000
degrees down there.
Well, it's a long way as well. Yeah.
You know, Arne Saknussemm was not going to have walked
like, 7000 miles in a in a the timeit takes for Hollywood to make a movie.
(00:43):
Yeah, it could have been a very long bookas well.
Yeah, but okay.
But there's so much heat down there.
There's so much heat.
There's so much energy beneath our feet,and we really suck.
Occasionally it does pop up occasionally,but but we got to be able to use it more
if we are using it.
Geothermal power?
Yes. Cooled?
Yes. Heat down below us.
And as we've talked about before,
(01:03):
to make electricity,what you really need is heat.
You burn stuff or you use nuclear,you heat water, you spin a turbine.
Right?
So you've got to be able to get the heatfrom beneath our feet and use that.
You can.
But it's one of these strategicdilemma problems that the greater
the source of heat close to the surface,the less stable it is,
because you've obviously got moltenrock coming up,
(01:27):
in a completely unstable environment,or you've got hot rocks.
Iceland, for instance,got a lot of hot rocks.
But in the recent past,Iceland is started to become less stable.
It's going through a volcanic cyclewhere when you when you say less stable,
you mean the heat is going upand down is fluctuating?
Well, the thing is, it's coming up
and it's destroying the pipesand the and the power stations.
(01:48):
Because although the pipes in the powerstations are fairly robust,
you know, a few thousand degreesof molten rock flowing over them
tends to cause severe amounts of,of not working anymore.
But do they alwaysis it always correlated with volcanoes?
It's not really.
It's we.
The thing is, you either he's got to drilla hole into the core of the earth,
(02:10):
which is about 6 or 7000 miles away,which is a long pipe
to remain stable with plates of the earthmoving around all over the place.
Or you you do it in a placewhere the heat from the from
the core of the earthis closer to the surface, which is the
the tectonic plates around the planetwhere they come together.
(02:31):
You tend to have fractures which allow
some of the heatto come up to the surface,
which is why you've got the Ring of firein the Pacific and things like that.
So we've got unstable California.
Yes, that's fault.
Yeah. UnstableI mean, Iceland's interesting.
They have, they that they're poweredpretty much completely from geothermal.
(02:52):
Yes. A very cheap powerthat's been been there a long time. Yes.
It's completely carbon free.
Yes. That that prices are on the floor.
They use it for heating as well,but they get the.
You need the hotter water for, for electricity, which they have.
The UK, we don't have a lot.
There are a couple down in Cornwall.
(03:12):
Yes, there are,but the reason the UK hasn't got a lot
is not because the heat isn't down there,but it hasn't come up.
The places where there is, there is
lots of,geothermal power is where the where
the heat is, is penetrating the crustand coming up to the surface.
Iceland
sits at the top of the defaultthat runs down the middle of the Atlantic,
(03:33):
which I don't knowif you seen all the nice, interesting
documentaries on the telly.
There's lots of bubbly thingsand strange shrimps and stuff that live on
all these little heat cones at the bottom,and they've got a place where the, the,
the cap of rock doesn'tbreak up that much,
but the heat is quite closeto the surface.
So the whole of Icelandis basically a big hot rock
(03:57):
and it's hot enough to generate steam.
But again, it's a dilemma.
The hotter you want it, the less stablethe source is going to be.
I think what we're saying isthere are various ways of doing it.
You know, as you said in Iceland,you could stick a straw in the ground and
it's boiling.Boiling water comes out immediately.
Yeah,but obviously everything's moving around.
You've got a volcano exploding.
So it's pretty difficult.
(04:19):
You've got the mid-rangewhere there's some stuff happening.
You call more,you can go down five kilometers or so.
It's it's expensive.
You get.
That's a different type of rock though,right.
the definition geologists will give youof hot rocks is not rocks that are hot,
but rocks that generate heat themselves.
So they're fundamentally radioactive,low level radioactivity.
Okay.
It used to be one of the old adages
(04:40):
of the nuclear industry that two weeksholiday in Cornwall will give you
a bigger radiation dose than workingin a nuclear power station for 20 years.
Really quite funny.
But true.
And what happens is that where you've gotrocks, granites and such similar,
which of which have got radioactivedecay built into the rock itself?
If you get site cracking systems inso the water table
(05:02):
can seep into these rocks,that water gets warmed up.
You can tap into that mike,which is slightly different from.
And you can pump water down as well.
You can. Yeah.
But obviously the thing is that, you know,
when you start looking at,the, the comparative cost
of doing these things, first of all,even in Cornwall, you've got to go down
(05:22):
79km,which is a long hold to remain stable.
You then probably got to pump waterdown the hole
to get heated to come back up again.
So you've got to use energyto get the energy.
And then you start looking at the mathsand say, is it worth pumping?
You know, thousands of tons of wateran hour down a hole
(05:43):
to get kilowatts outwhere if I use the land
that I'm drilling the hole onand put solar panels on it, I'll get more.
Yeah.
Because I think, I think Cornwallis being about 35 million to generate
kind of a couple of mega of electricity,which which doesn't make sense.
I mean, we're no commercial organizationwill do it unless it's like the, the,
the Iceland or Chileor somewhere like that or the Great Rift
(06:05):
Valley in Kenya does a lot.
Yeah, yeah. Again, it's near the surface.
There is there is new technologycoming out of principally America,
which is built on the tech embeddedfor shale, which is basically fracking.
So you're going down to
I don't know if it's radioactiveor just hotter areas,
but you're getting more,you're getting shallower,
and then you're fracturing the rockusing the same fracking technology
(06:26):
you're putting fracking fluid in,which is essentially water.
You're heating it upand pushing it out again.
And there are a few wells drilled,and they think they can scale
that significantly.
And you don't go down as deep.
Yeah.
So then you can get black waterand gas out of your plumbing.
Well, it's you know,the problem is if you start messing
with the geology underneath somewhere,you should expect changes.
(06:47):
And all of our infrastructureis built on the basis
that the ground it's built onis not going to change very much.
This is the Iceland problem.
are you going to spend millions,potentially
billions on a new power stationin Iceland?
Only for the geologyto move around slightly
and wipe it all out in an afternoon?
I think that's the problem with geothermal
(07:08):
because you think about itis is drilling right.
We drill stuffall the time for oil and gas.
The thing is, on a gas, well,you get a ton of money out of it, right?
You hit it only when you win.
Yeah. Lots of holes are drilledor used to be.
Not so much now,because geological analysis.
But you used to drill a lot of holesbefore you, before you win a.
But even if you do that,the prize is very, very, very big.
(07:28):
You go oil coming out for yearswith geothermal.
Same drilling.
You're getting hot water.
It's just not worth as much. Yeah.
Because it's the hot water's cheap.
We throw billions of tons of hotwater away every year.
everywhere.
That's a that's a heating episode.
Let's get on to that another time.
But but yeah, I meanI think geothermal is really interesting.
(07:50):
But the place, you know,you just can't do it
in that many placeswhere the heat is close to the surface
and drilling downfurther is too expensive.
So I think it's it's a little bitlike wind.
You could do it in certain placesand it's worth doing certain places.
Yeah. But it's not going tosolve the energy transition.
It's.
(08:11):
But we'll have some because of the waythe economics is working now.
Everything is becoming peggedagainst water, solar and batteries cost.
Yeah.
And that's going to be the decidingcut off line
for every technology going forward.
I agree completely.
And I more and more,
more and more as every day goes past.
(08:33):
I think it's solar on batteries for 80%and you've got a bit of wind,
bit of geothermal, some nuclear, alittle bit of fossil for whatever reason.
And we're done.
Thanks so much for tuning into today's episode.
If you enjoyed the conversation,don't forget to like, subscribe
and leave us a review!
It really helps us grow and continuebringing you valuable content.
If you're curious
to learn more about Beaverbrook Energyand how we're navigating the future
(08:56):
of energy,feel free to reach out to us directly.
And for those looking for quick,actionable insights on the energy
transition, be sure to subscribeto our ten second climate newsletter,
delivered every weekend
with a central intelligence to helpbusiness leaders stay ahead of the curve.
We appreciate you listening,
and we look forward to having youjoin us again next time.
Stay informed, stay engaged and take care.
Welcome to Ten Minute Climate, the podcastbrought to you by Beaverbrook Energy.
Join Max I am Max and Tony.
Hi, I'm Tony, who between themhave got over 70 years of experience
in the energy industryand they're here to share it with you.
Each episode they'll cut through myths,answer the questions you've always wanted
to ask, and break down the latest newsabout the energy transition.
(00:22):
It's everything you need to knowdelivered in just ten minutes.
So let's get started.
The thing. I'd been fascinated about thisfor a long time.
Journeys in the sense of the earth,wasn't going to work because it's 6000
degrees down there.
Well, it's a long way as well. Yeah.
You know, Arne Saknussemm was not going to have walked
like, 7000 miles in a in a the timeit takes for Hollywood to make a movie.
(00:43):
Yeah, it could have been a very long bookas well.
Yeah, but okay.
But there's so much heat down there.
There's so much heat.
There's so much energy beneath our feet,and we really suck.
Occasionally it does pop up occasionally,but but we got to be able to use it more
if we are using it.
Geothermal power?
Yes. Cooled?
Yes. Heat down below us.
And as we've talked about before,
(01:03):
to make electricity,what you really need is heat.
You burn stuff or you use nuclear,you heat water, you spin a turbine.
Right?
So you've got to be able to get the heatfrom beneath our feet and use that.
You can.
But it's one of these strategicdilemma problems that the greater
the source of heat close to the surface,the less stable it is,
because you've obviously got moltenrock coming up,
(01:27):
in a completely unstable environment,or you've got hot rocks.
Iceland, for instance,got a lot of hot rocks.
But in the recent past,Iceland is started to become less stable.
It's going through a volcanic cyclewhere when you when you say less stable,
you mean the heat is going upand down is fluctuating?
Well, the thing is, it's coming up
and it's destroying the pipesand the and the power stations.
(01:48):
Because although the pipes in the powerstations are fairly robust,
you know, a few thousand degreesof molten rock flowing over them
tends to cause severe amounts of,of not working anymore.
But do they alwaysis it always correlated with volcanoes?
It's not really.
It's we.
The thing is, you either he's got to drilla hole into the core of the earth,
(02:10):
which is about 6 or 7000 miles away,which is a long pipe
to remain stable with plates of the earthmoving around all over the place.
Or you you do it in a placewhere the heat from the from
the core of the earthis closer to the surface, which is the
the tectonic plates around the planetwhere they come together.
(02:31):
You tend to have fractures which allow
some of the heatto come up to the surface,
which is why you've got the Ring of firein the Pacific and things like that.
So we've got unstable California.
Yes, that's fault.
Yeah. UnstableI mean, Iceland's interesting.
They have, they that they're poweredpretty much completely from geothermal.
(02:52):
Yes. A very cheap powerthat's been been there a long time. Yes.
It's completely carbon free.
Yes. That that prices are on the floor.
They use it for heating as well,but they get the.
You need the hotter water for, for electricity, which they have.
The UK, we don't have a lot.
There are a couple down in Cornwall.
(03:12):
Yes, there are,but the reason the UK hasn't got a lot
is not because the heat isn't down there,but it hasn't come up.
The places where there is, there is
lots of,geothermal power is where the where
the heat is, is penetrating the crustand coming up to the surface.
Iceland
sits at the top of the defaultthat runs down the middle of the Atlantic,
(03:33):
which I don't knowif you seen all the nice, interesting
documentaries on the telly.
There's lots of bubbly thingsand strange shrimps and stuff that live on
all these little heat cones at the bottom,and they've got a place where the, the,
the cap of rock doesn'tbreak up that much,
but the heat is quite closeto the surface.
So the whole of Icelandis basically a big hot rock
(03:57):
and it's hot enough to generate steam.
But again, it's a dilemma.
The hotter you want it, the less stablethe source is going to be.
I think what we're saying isthere are various ways of doing it.
You know, as you said in Iceland,you could stick a straw in the ground and
it's boiling.Boiling water comes out immediately.
Yeah,but obviously everything's moving around.
You've got a volcano exploding.
So it's pretty difficult.
(04:19):
You've got the mid-rangewhere there's some stuff happening.
You call more,you can go down five kilometers or so.
It's it's expensive.
You get.
That's a different type of rock though,right.
the definition geologists will give youof hot rocks is not rocks that are hot,
but rocks that generate heat themselves.
So they're fundamentally radioactive,low level radioactivity.
Okay.
It used to be one of the old adages
(04:40):
of the nuclear industry that two weeksholiday in Cornwall will give you
a bigger radiation dose than workingin a nuclear power station for 20 years.
Really quite funny.
But true.
And what happens is that where you've gotrocks, granites and such similar,
which of which have got radioactivedecay built into the rock itself?
If you get site cracking systems inso the water table
(05:02):
can seep into these rocks,that water gets warmed up.
You can tap into that mike,which is slightly different from.
And you can pump water down as well.
You can. Yeah.
But obviously the thing is that, you know,
when you start looking at,the, the comparative cost
of doing these things, first of all,even in Cornwall, you've got to go down
(05:22):
79km,which is a long hold to remain stable.
You then probably got to pump waterdown the hole
to get heated to come back up again.
So you've got to use energyto get the energy.
And then you start looking at the mathsand say, is it worth pumping?
You know, thousands of tons of wateran hour down a hole
(05:43):
to get kilowatts outwhere if I use the land
that I'm drilling the hole onand put solar panels on it, I'll get more.
Yeah.
Because I think, I think Cornwallis being about 35 million to generate
kind of a couple of mega of electricity,which which doesn't make sense.
I mean, we're no commercial organizationwill do it unless it's like the, the,
the Iceland or Chileor somewhere like that or the Great Rift
(06:05):
Valley in Kenya does a lot.
Yeah, yeah. Again, it's near the surface.
There is there is new technologycoming out of principally America,
which is built on the tech embeddedfor shale, which is basically fracking.
So you're going down to
I don't know if it's radioactiveor just hotter areas,
but you're getting more,you're getting shallower,
and then you're fracturing the rockusing the same fracking technology
(06:26):
you're putting fracking fluid in,which is essentially water.
You're heating it upand pushing it out again.
And there are a few wells drilled,and they think they can scale
that significantly.
And you don't go down as deep.
Yeah.
So then you can get black waterand gas out of your plumbing.
Well, it's you know,the problem is if you start messing
with the geology underneath somewhere,you should expect changes.
(06:47):
And all of our infrastructureis built on the basis
that the ground it's built onis not going to change very much.
This is the Iceland problem.
are you going to spend millions,potentially
billions on a new power stationin Iceland?
Only for the geologyto move around slightly
and wipe it all out in an afternoon?
I think that's the problem with geothermal
(07:08):
because you think about itis is drilling right.
We drill stuffall the time for oil and gas.
The thing is, on a gas, well,you get a ton of money out of it, right?
You hit it only when you win.
Yeah. Lots of holes are drilledor used to be.
Not so much now,because geological analysis.
But you used to drill a lot of holesbefore you, before you win a.
But even if you do that,the prize is very, very, very big.
(07:28):
You go oil coming out for yearswith geothermal.
Same drilling.
You're getting hot water.
It's just not worth as much. Yeah.
Because it's the hot water's cheap.
We throw billions of tons of hotwater away every year.
everywhere.
That's a that's a heating episode.
Let's get on to that another time.
But but yeah, I meanI think geothermal is really interesting.
(07:50):
But the place, you know,you just can't do it
in that many placeswhere the heat is close to the surface
and drilling downfurther is too expensive.
So I think it's it's a little bitlike wind.
You could do it in certain placesand it's worth doing certain places.
Yeah. But it's not going tosolve the energy transition.
It's.
(08:11):
But we'll have some because of the waythe economics is working now.
Everything is becoming peggedagainst water, solar and batteries cost.
Yeah.
And that's going to be the decidingcut off line
for every technology going forward.
I agree completely.
And I more and more,
more and more as every day goes past.
(08:33):
I think it's solar on batteries for 80%and you've got a bit of wind,
bit of geothermal, some nuclear, alittle bit of fossil for whatever reason.
And we're done.
Thanks so much for tuning into today's episode.
If you enjoyed the conversation,don't forget to like, subscribe
and leave us a review!
It really helps us grow and continuebringing you valuable content.
If you're curious
to learn more about Beaverbrook Energyand how we're navigating the future
(08:56):
of energy,feel free to reach out to us directly.
And for those looking for quick,actionable insights on the energy
transition, be sure to subscribeto our ten second climate newsletter,
delivered every weekend
with a central intelligence to helpbusiness leaders stay ahead of the curve.
We appreciate you listening,
and we look forward to having youjoin us again next time.
Stay informed, stay engaged and take care.
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