♪ ♪ ♪ ♪ MILES O'BRIEN: Sometimes, the best solutions just percolate to the surface and report for duty.

You can almost hear them saying, "Pick me, pick me!"

BILLY THOMAS: We're actually at the Davis-Schrimpf Mud Pots... O'BRIEN (voiceover): Which is why I'm here... THOMAS: ...world-renowned mud pots that occur naturally.

O'BRIEN: ...as far south as you can go in California-- near the Salton Sea-- to see an oddity: the Davis-Schrimpf Mud Pots.

My guide is geoscientist Billy Thomas.

Here, carbon dioxide bubbles up through pools of mud.

I think Earth has indigestion.

THOMAS: Yeah.

O'BRIEN: Forming six-foot mounds-- mini mud volcanoes called gryphons that walk across the landscape.

(bubbling, sloshing) Doesn't have any particular smell.

Just good clean mud.

THOMAS: Yeah.

O'BRIEN: This is the end of the line for the legendary San Andreas Fault.

Deep below the surface, tectonic plates are ripping apart here, allowing a novelty like these mud pots to emerge.

But it also brings something more useful within striking distance-- very hot water.

You're essentially pulling apart the continental crust and the, the heat source below us is actually a little bit closer to our feet.

It gives us the ability to drill wells and actually produce this hot fluid at depths that we can reach with a drilling rig.

O'BRIEN: Billy is the senior director of geothermal resources at BHE Renewables.

One of their power plants is nearby.

We have about 25 production wells.

O'BRIEN (voiceover): I was here to learn about the heat beneath our feet.

And how it could revolutionize, and decarbonize, our electric grid.

Geothermal is the residual heat left over from the formation of the planet and from the decay of radioactive particles deep below the earth's surface.

The deeper you go, the hotter it gets.

At a geothermal electric power plant, they drill down far enough to reach very hot water to generate power.

Another well injects the water back into the ground.

The wells here are between 2,000 and 10,000 feet deep.

The briny 600-degree water they tap into can spin enough turbines to generate power for about 300,000 homes.

It's renewable, nearly carbon-free, and it's always on.

There aren't many places in the world that can get you that kind of capacity in a practical way, right?

Right-- no, really, what we benefit from here is having the shallow heat source, but also from the fractured nature of the area here.

O'BRIEN: The first commercial geothermal power plant opened in Italy in 1913.

For decades, the idea was limited to places where geological faults allow heat from the Earth's interior to reach the surface.

As a result, less than one-half of 1% of electricity in the world is generated this way.

But now, a new kind of geothermal power is emerging.

This new approach means it's possible nearly anywhere.

To learn more, I went to Texas.

When you think about Texas, you think about fossil fuels, right?

This is the land of oil.

The people, the technology that are so good at recovering all that oil and gas from beneath the surface can be pretty easily pivoted to go after another energy resource that's completely renewable.

At the center of this transformation is engineer Cindy Taff, who spent 35 years drilling oil and gas wells for Shell.

She eventually ran the company's unconventional oil and gas business, overseeing horizontal drilling and hydraulic fracturing.

So, she's right at home here, drilling thousands of feet into the earth, surrounded by roughnecks.

Feels like 100 years of thinking about how to poke holes in the ground, right here, right?

- Correct.

O'BRIEN: You know, it's amazing what a science this is, actually, right?

TAFF: Yes.

It's a science, but it's also an art.

- Yeah?

Yeah, and I'll be honest with you, the oil and gas industry has taken what was an art and has made it a science.

O'BRIEN: She's taking the science to another level-- prospecting for hot rock instead of cold crude.

She is C.E.O.

of a Houston-based startup called Sage Geosystems, a company on a mission to make geothermal ubiquitous by repurposing a drilling technique with a bad reputation-- fracking.

So, as far as these guys are concerned, it doesn't really matter, it's the same process.

TAFF: Exactly.

We can leverage, right now, the oil and gas industry, the infrastructure of the oil and gas industry, to scale this technology immediately.

We don't have to wait for, you know, knowledge and skills and expertise because the oil and gas industry already has it.

O'BRIEN: The drilling techniques and technologies pioneered by the oil and gas industry are now driving a surprising energy transition.

For the first time, it is becoming economically feasible to reach intensely hot rock deep underground almost anywhere on Earth.

The new approach is known as an "enhanced geothermal system," or E.G.S.

♪ ♪ The concept is straightforward: drill deep into extremely hot rock.

If the rock is not naturally permeable, fracture it to create an artificial underground reservoir.

Then pump water into those cracks.

As the water circulates through the superheated rock, it returns to the surface hot enough to generate electricity.

It is fracking, but the industry says it doesn't use toxic chemicals.

Just water and a more benign polymer.

But what about earthquakes?

Enhanced geothermal systems have triggered small-- but sometimes noticeable-- temblors.

In 2017, an enhanced geothermal project in South Korea triggered a magnitude 5.5 earthquake that injured more than 130 people and caused roughly $75 million in damage.

But the well was unmonitored, and they drilled in a seismically active area.

The risk isn't zero.

That's why geothermal projects are closely monitored, with operators prepared to dial back or halt operations if seismic activity increases.

TAFF: The oil and gas industry has fracked in sedimentary rock for years, and we know how to mitigate induced seismicity.

And quite frankly, the rock is so soft, you usually don't get induced seismicity in sedimentary rock.

O'BRIEN: While E.G.S.

seems like a novel technology in the age of renewable energy, its origins are surprising.

TV NARRATOR: In 1974, the first well of the two-hole system was drilled at Fenton Hill.

O'BRIEN: Enhanced geothermal began, ironically, at the birthplace of a seismic shift in warfare, Los Alamos, New Mexico, where scientists devised the first atomic bombs.

TV NARRATOR: At the Los Alamos Scientific Laboratory, geoscientists are investigating this procedure.

It is known as the Hot Dry Rock project.

O'BRIEN: Jeff Tester was on the team.

One method of extracting heat or mining heat from under the surface of the earth is to create a reservoir.

We were trying to go into regions where the rock was not necessarily full of steam or hot water and trying to actually make a reservoir ourselves.

O'BRIEN: Today, Tester is a senior engineering professor at Cornell University.

TESTER: The people there were creative and they were thinking, a lot of them had been-- started in World War II, so they were used to trying new things.

And they said, "What could we do that would be different?"

O'BRIEN: They borrowed techniques and tools from the oil industry, and then made them more heat and pressure-tolerant.

They developed methods to track a drill bit deep underground.

And they were among the first to hydraulically fracture rock to make subterranean reservoirs for geothermal energy production.

It worked.

TV NARRATOR: On June 7, 1977, cold water pumped down one hole flowed from the other at 130 degrees Celsius after circulating through the hot rock deep underground.

O'BRIEN: At the time, Los Alamos engineers envisioned building two commercial-scale power plants running on heat from Hot Dry Rock by 1988.

But that never happened.

We had other sources of low-cost fossil fuels that were coming online.

And, uh, so the, the, the sort of geopolitics at the time did not favor a sustained commitment to, uh, to geothermal.

O'BRIEN: Tester remains a tireless pioneer whose message resonated in an unlikely place with an unlikely person.

JAMIE BEARD: Project InnerSpace was, was founded, uh, on the thesis that we should be doing geothermal energy at oil and gas scale.

O'BRIEN: Her name is Jamie Beard.

She's a persistent and increasingly influential advocate for geothermal energy.

She leads a nonprofit called Project InnerSpace, focused on building both the ecosystem and the enthusiasm to scale geothermal worldwide.

To catch up with her, I came to Houston for the Davos of the energy industry-- CERAWeek by S&P Global, an annual gathering of oil executives, policymakers, and a growing number of clean energy players.

She calls her space here the Geothermal House.

It leans into the theme, with a distinctly subterranean flair.

When I walked in, she was deep in conversation with Cindy Taff.

How are you?

Cindy... Good to see you.

And Jamie, it's good to see you, how are you?

(voiceover): It's a room devoted to fostering partnerships with the oil and gas industry.

It's an ironic turn for Jamie.

JOSEPH HAZELWOOD (over radio): O'BRIEN: She's been an environmental activist all her life.

For her, it began in 1989 after the devastating Exxon Valdez oil spill in Alaska.

(cawing) BEARD: It was video that I saw of an oil-soaked bird, or it was a duck or something.

Crushed by that and became obsessed with crashing the oil and gas industry.

And I just went, went off the charts on tree-hugging from there.

O'BRIEN: She became a lawyer, believing it might be the most effective way to fight for the environment.

But another oil spill changed her thinking.

BP's Deepwater Horizon well blew out in the Gulf of Mexico in 2010.

Jamie was distressed to see big law firms lining up to defend the oil company.

So she quit.

This is the story of two oil spills and a... And the future of geothermal.

O'BRIEN: Something like that, yeah.

She joined an energy storage company working on a device that was potentially useful on drilling rigs.

And so she found herself in the oil patch of all places, inside enemy lines.

BEARD: They made fun of us, and laughed at us, yes.

And we were the geeks in the trailer.

But, but what they were doing was amazing.

I grew to really respect the folks that were executing in the field, and I think they grew to really respect the fact that we were geeks bringing high tech stuff to their operations.

It's so easy to dislike the other if you don't know the other.

It's really hard to dislike people if you're sitting in front of them.

O'BRIEN: Yeah.

Around this time, she read an article about a landmark study on geothermal energy.

The lead author was Jeff Tester, then at M.I.T.

It concluded enhanced geothermal systems could provide 100 gigawatts of electricity-- about 10% of the U.S.

electric grid-- by 2050.

This article was like, man, if we just solved this, this set of challenges, we just unleash this huge resource on the world.

So I read the article, turned around, and read the report ten times over.

And it was like, if it's a set of engineering challenges that are drilling related, the oil and gas industry does that every day in oil and gas.

Why not?

Why can't you just put them together?

O'BRIEN: She read everything she could find and called anyone she could think of.

For every success there were, like, a hundred fails for a long time, but individuals who got so excited that they then decided to start companies and then they started pitching those companies and concepts to oil and gas entities, that caused a, a watershed moment.

O'BRIEN: Her obsessive campaign coincided with a big change in the industry-- new horizontal drilling and fracking techniques were unlocking previously unreachable oil.

In places like the Permian Basin, once thought to be tapped out, the oil and gas were gushing faster than ever.

The same techniques and technology made geothermal much more attainable.

Today, Jamie counts more than a hundred geothermal startups globally.

An industry has started to take root.

So you're the Johnny Appleseed of geothermal?

Planting seeds as ideas that then grew into startups and other things, there is probably a parallel there.

Yes, yes.

O'BRIEN: One of those seeds was the company co-founded by Cindy Taff and named after Jamie's son, Sage.

Their offices are also in Houston, located inside the headquarters of Nabors Industries, an early investor in Sage.

Nabors is one of the world's largest oil and gas drilling contractors.

Cindy gave me a quick tour of their Remote Operations Center.

TAFF: What they're displaying up here is real-time data from their drilling rigs around the world.

It all comes together to determine the performance of actually making hole.

As in, how fast you're making it, or accurately drilling that hole to place it where you want it.

O'BRIEN: It soon became clear to her this technology could easily be adapted to improve the hunt for hot rock-- geothermal energy.

TAFF: Unfortunately, at Shell, it wasn't a big part of the renewable energy plan, which I, I never quite understood, because we had all the resources.

So it's a little bit odd.

It seems like it's overlooking an obvious... easy transition.

You got a standing army that knows how to poke holes in the ground, right?

Not only knows how to poke holes in the ground, but knows where to poke holes in the ground, knows how to build facilities, knows how to project manage, drive costs down.

Yeah, so what we're doing in geothermal is an overlay to what oil and gas does.

♪ ♪ O'BRIEN: As they began thinking beyond the borehole-- and beyond oil and gas-- it dawned on Cindy and her team at Sage that there was another resource down there still largely untapped: pressure.

(oil sprays) When you pump water deep underground, the pressure in the reservoir pushes it back to the surface.

Harness that pressure-- not the heat-- and you may have a way to store energy.

To see how it works, I went to Christine, Texas, about 50 miles south of San Antonio, where Cindy was building Sage's first geothermal energy storage facility.

How's everything going?

TAFF: Good to see you, yeah.

O'BRIEN: It's getting bigger and better here.

Isn't it?

TAFF: Absolutely.

O'BRIEN: They were digging a huge, two million gallon reservoir.

It is the most visible feature in a novel system to create a battery out of the earth itself.

When an intermittent renewable like solar or wind produces excess energy, it powers a pump that injects water from this artificial lake into a fractured reservoir 9,600 feet below.

TAFF: Putting the water into the fracture, operating that fracture like a balloon, so, storing it under pressure.

And then when you need the energy, you open the valve at the surface.

That fracture is wanting to naturally close and go back to its initial state.

And when it does, it jettisons the water back to surface.

O'BRIEN: It will be under high pressure, up to 5,000 pounds per square inch.

That flow can spin what's called a Pelton turbine, essentially a high-tech water wheel you'd see at an old mill.

Sage claims it could be enough to run a generator for up to 24 hours, keeping the electrons flowing when wind and solar are not producing.

TAFF: When you go to the field, one thing that you'll learn, and we, you know, I learned it my whole career in oil and gas, is you have to listen to what the well is telling you.

You have to learn from the well, and, and so that's what we did.

So this is solving one of the pieces of the puzzle for the energy grid and helping wind and solar to optimize their assets.

O'BRIEN: Sage found an unlikely partner for this geo storage idea.

It is getting up in age compared to other coal plants.

O'BRIEN (voiceover): A coal plant operator a few miles away wanted to transition to solar.

And he needed a storage solution.

Cindy and I took a spin over to meet Craig Courter.

He thinks out of the box.

Um, he's got a passion for what he does and he's got an entrepreneur, you know, mindset.

O'BRIEN (voiceover): At the time, Craig ran the San Miguel Electric Cooperative Power Plant.

Built more than 40 years ago, it burns lignite coal-- the lowest grade.

It is the most carbon-intensive fossil fuel.

The coal is strip-mined from the land surrounding the plant, feeding a relentless cycle of extraction, combustion, and pollution of the air, water, and climate.

The plant is headed for retirement, and Craig wanted to replace it with a 400-megawatt solar farm.

But his challenge, of course, is what happens when the sun goes down.

To keep the power flowing around the clock, he turned to Sage and Cindy.

We have to start thinking big because we have a lot of energy that's going to be end of life around 2030 to 2040.

So we have to start getting outside the box and thinking about how are we going to put this power on the grid?

♪ ♪ O'BRIEN: Craig is good at fanning all kinds of flames to serve his purposes.

Yeah, y'all thought the party lights were just for looks.

That's really the lighting.

(chuckles) O'BRIEN: He invited us to his ranch for a Texas-style barbecue.

After we finished the rib-eyes, sausages, and jalapeno poppers... Mm!

(voiceover): ...we started chewing the fat on geothermal energy.

I thought you had to be at a volcano.

When I heard that there was geothermal in South Texas, I was like, "What?

(laughs) Where?"

O'BRIEN (voiceover): Just about everyone here owed their livelihoods to the extraction and combustion of fossil fuels.

You know, it's interesting having all these oil and gas people singing the praises of renewable.

What's that like?

Oh, it's great, I mean we've focused on affordable energy for the last 20, 40 years, right?

So this is a new form of affordable energy, so I think the oil and gas industry is the right industry to bring it to where it is today to the cost that we need to scale going forward.

♪ ♪ O'BRIEN: The federal government has been instrumental as well.

In 2018, the Department of Energy funded the University of Utah to pick up where Jeff Tester and his team at Los Alamos left off in the late '70s.

The Utah FORGE project helped prove the viability of Enhanced Geothermal Systems.

♪ ♪ Now, a geothermal startup called Fervo Energy has leased land nearby.

It's building a 500-megawatt geothermal power plant, one of the first of its kind.

BEARD: What Utah FORGE did was de-risk a specific geology in a specific place that then Fervo piggybacked on-- replication of that FORGE model is something that needs to happen.

♪ ♪ O'BRIEN: In 2026, Fervo raised nearly $1.9 billion in an initial public offering.

It's a sign that geothermal may finally be ready for prime time.

But Jamie Beard says it's not enough.

I do see risk in having startups carry the day.

Because 90% of startups fail.

To build the future of energy, we can't build it on the back of a few startups.

There are oil majors that are out there thinking, "How can we do this ourselves?"

And that is a massive success.

O'BRIEN: Before becoming the energy secretary under President Trump, Chris Wright was C.E.O.

of a fracking company that invested $10 million in Fervo.

As secretary, he has promoted geothermal as part of U.S.

energy strategy.

Evidently, it's in sync with an energy policy so focused on drilling.

There's a bipartisan nature to this particular type of energy.

Why is that?

Part of the great thing about geothermal is you call it different things.

All of them are honest.

Left: clean, green, renewable.

Small footprint, all these things-- great!

Right: abundant, secure, ubiquitous, oil and gas industry jobs, bam, bam, bam-- all that is true.

All of it can be true at the same time.

O'BRIEN: Back in Christine, Texas, while the potential of geo-storage remains strong, its future is not as clear.

It's been about seven months since we were here watching that well being drilled, and the project is complete, ready to be plugged into the grid.

The solar project was delayed by budgetary uncertainties in Washington, and Craig Courter has left to become an energy consultant.

But the utility is still pursuing the transition from coal to solar.

So the plot has thickened a little bit.

But for now, let's go just take a look at this storage facility and see how that would work here, or for that matter, anywhere else.

Cindy met me at the site.

Holy cow, look at this place.

(Taff chuckles) It's a drastically changed scene here.

- It is.

- It really is.

It's finished.

O'BRIEN: Even without solar panels, they hope to validate the technology by pumping water underground when electricity from the grid is cheap, and then releasing it to generate and sell power when demand and the price of electricity are highest.

Energy arbitrage.

It's when the wind is dying down, when the sun is just coming up, or in, in the evenings when the wind's dying down again or the sun's going down.

Those are the two demand areas.

O'BRIEN: The techniques they learn here will help them refine their efforts to generate geothermal electricity with hot rock.

But they can build energy storage a lot faster.

TAFF: It's not a huge breakthrough, but it is an open-mindedness to use existing technology in a different manner.

O'BRIEN: Geothermal energy runs 24/7-- and it's renewable.

It could help make the grid both cleaner and more reliable-- powering not just an energy transition, but a workforce transition as well.

TAFF: If you go back 15 years and you think about where wind and solar was, I don't know about you, but I used to think, ah, these, these technologies are never gonna work.

They're never gonna be commercial.

O'BRIEN: Right.

- But they are.

And so it was the opportunity to be on that learning curve with a new technology, but one that I had a skill set around-- I would love to look back, you know, ten, 15 years from now and say, "Hey, I was part of that.

"I was part of making, you know, geothermal a bigger piece of the energy pie."

The timing seems to be perfect.

♪ ♪ O'BRIEN: It's a promising solution that still needs to be proven commercially at scale.

But it shows that potentially groundbreaking ideas can bubble up-- when smart, skilled people get together to do some pipe dreaming.

♪ ♪ ♪ ♪ ♪ ♪