Why Aren’t Geothermal Power Plants Everywhere?

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Wind and solar are becoming more popular by the minute and there’s enough energy coming from the sun and the wind to power the world. But there’s a problem.

Because of their intermittency, we need vast amounts of energy storage and we can’t install solar and wind farms wherever we want.

But what if I told you that there’s a virtually limitless, clean, reliable and sustainable source of renewable energy that’s available 24/7 all over the world, and that could provide all the energy we’ll need for the next 2+ MILLION YEARS? It’s geothermal energy and it’s beneath your feet as we speak. So why aren’t we building these power plants everywhere? I’m Ricky, and this is Two Bit da Vinci.

What is geothermal power?

Geothermal power is one of the most promising sources of renewable energy, and it’s also one of the most underutilized. It works by capturing heat from the earth’s core and transporting it to the surface where we use it for heating or convert it into electricity.

In the latter case, geothermal power plants work similarly to other thermal power plants in that they use hot pressurized steam to power a steam turbine that drives a generator. However, instead of burning fossil fuels to generate hot steam, we use heat from the Earth’s core.

And there is A LOT of heat inside the Earth.

How much geothermal energy is there?

This heat is, in part, a remnant from when the Earth initially formed, but a significant portion of it comes from nuclear fission reactions of decaying radioactive elements present in the Earth’s core.

Because of all that internal energy, the Earth’s solid inner core is at a scorching 10,800 °F (6,000 °C), almost as hot as the Sun’s surface. That heat is conducted to the outer layers, creating a geothermal temperature gradient that extends to the Earth’s crust, where we can tap into this heat.

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Now, for different reasons that I won’t get into, we can’t drill any deeper than about 5.56 miles (10km) or 1/10 of the crust’s maximum thickness.

At that depth, the Earth’s temperature gradient or geothermal gradient has an average temperature of about 450 °F (250°C). Sure that’s hot, but it’s not crazy hot, but even still,, there are approximately 1.3×10^27 joules of available thermal energy!

That’s 13 followed by 26 zeros!

To understand how mind-bogglingly-large this number is, consider that the global energy consumption in 2021 was almost 6.10^20 joules. So, 1.3×10^27 joules is enough energy to power the world for another 2.17 million years by 2021 standards.

So geothermal is, for all practical purposes, an inexhaustible resource; one we’ve been using for thousands of years as a source of heat and since 1904 to produce electricity, when Prince Piero Ginori Conti, an Italian businessman and politician, invented the geothermal power plant in Larderello, Tuscany [3].

But why does all this matter?

I mean, we’ve all heard similar claims about the total amount of available solar energy, for example.

Geothermal’s underlying importance is that, unlike solar and wind, it doesn’t suffer from intermittency. As I pointed out in previous videos, this intermittency means we’ll need massive amounts of grid storage worldwide, over 20,000 times what we have now, to replace fossil fuels with wind and solar.

Additionally, solar is only a viable option in places that get a lot of sunshine, and wind speeds are only sufficient to power turbines in certain areas around the world.

In contrast, geothermal power plants can provide clean, carbon-free energy in a reliable and predictable way, 24 hours a day, 365 days a year, making it one of the few available options to replace gas and diesel turbines for base load power generation.

Coupled with energy storage technologies like Lithium-ion batteries for mobile applications, geothermal could help us ditch fossil fuels once and for all.

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Additional perks of geothermal power

While this alone should be enough to convince most, here are a couple more facts about geothermal energy that make it an awesome energy source:

#1 Geothermal power plants have a very small footprint.

Compared to most other energy sources, geothermal power plants also make better use of land. They only take up an average 0.1 acres (404 m²) per gigawatt-hours per year of installed capacity.

That’s only half a tennis court per gigawatt-hour compared to hydro’s massive 27 acres (109,000 m²), coal’s 0.9 acres (3,642 m²), solar plants’ 0.8 acres (3,237 m²) and wind farms’ 0.33 acres (1,335 m²).

In fact, its footprint is only second to Nuclear power plants that average 0.095 acres (384 m²) per gigawatt-hour per year installed capacity.

#2 They can leverage the oil industry’s knowhow and equipment.

Building a geothermal power plant is very similar to drilling an oil or gas production well. This is a huge incentive for big oil companies to invest in this technology as fossil fuels run out or are eventually phased out, because it would let them repurpose millions of dollars’ worth of equipment and infrastructure, while providing a steady source of income to replace their previous oil revenue.

What’s more, this will also mean that oil-field industry workers and specialized engineers won’t be left without a job when we replace fossil fuels, since their skills will continue to be in high demand.

#3 We can use it to repurpose waste water.

California houses the largest geothermal power complex in the world, The Geysers, which produces around 900 megawatts of electricity. The plant uses waste water from several nearby towns to recharge the wells and keep them producing energy.

#4 Geothermal is everywhere!

Finally, as I said before, geothermal energy is present below the surface of our entire planet, so we could, in theory, set up a geothermal power plant anywhere we need one.

Now, if you’ve made it this far along the video, you’re probably just as excited about geothermal as I am, and you’re probably just as puzzled. I mean… why aren’t we building these plants everywhere?

Worldwide geothermal energy production

To be fair, we have built a good number of geothermal power plants around the world, but these are nowhere near as many as we need or could build.

The total installed geothermal power capacity worldwide reached only 15.6 Gigawatts in 2021, amounting to only a little under 0.6% of our current power consumption.

In the US, statistics are even worse. Even though in California, geothermal provides 60% of the power along the Northern California coast [4] (I bet you didn’t know that) and that the US is the largest geothermal energy producer in the world, here, geothermal only provides 0.4% of the total energy mix with the 60 power plants currently in operation [5]. That’s why I say this is one of the most underutilized sources of energy.

If you’re thinking,

“There must be something wrong with geothermal energy, then!”

Well… there is. But to understand what that is, we’ll have to go a bit deeper into how geothermal energy production actually works.

How does geothermal energy work?

In essence, we use geothermal for two main applications: as a direct source of heat, or to transform that heat into electricity.

Geothermal Heat Pumps

When we talk about direct use, we mean directly transferring heat from the earth to residential, commercial, industrial and recreational buildings through district heating, geothermal heat pumps and other technologies.

I made a great video about geothermal heat pumps, and my good friend Matt Ferrel from Undecided is also installing one for his net-zero home. I suggest you check those videos out when you finish watching this one, links in the description.

Geothermal power plants

Geothermal power plants, on the other hand, are what we use to produce electricity from the Earth’s heat. As I said at the beginning of this video, all of these power plants use steam-powered turbines to power electricity generators. The rest of the system comes in several variations, the most common of which are:

Dry steam
Flash, and
Binary geothermal power plants
Dry steam geothermal energy

The first technology was the one originally invented by Piero Ginori in Italy. This setup feeds hot water vapor or steam extracted from hot underground permeable reservoirs directly into the turbine.

The steam is then cooled, condensed and pumped back into the reservoir as liquid water through an injection well.

Dry steam power plants are not that common but some of the units in The Geysers are dry steam generators.

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Flash geothermal power plants

Contrary to dry steam, flash geothermal power plants extract high-pressure, high-temperature LIQUID water from the production well into a flash tank where it evaporates.

This produces the high pressure steam that is then fed into the turbine.

Some dual and triple flash plants use two or three flash tanks to generate even more steam and a higher power output than single flash geothermal power plants, but at a higher cost.

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Binary cycle geothermal

Finally, we have binary cycle power plants that use one fluid, usually liquid water, to extract heat from the permeable reservoir and transfer that heat through a heat exchanger to a working fluid, usually an organic compound with a much lower boiling point, which readily evaporates producing the steam that powers the turbine.

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Binary plants are great because they can work at much lower temperatures and therefore at more shallow depths than dry steam and flash power plants.

All these technologies are mature and have already been deployed at commercial scale worldwide. But, as you can probably guess, they have several drawbacks.

The pitfalls and Limitations of geothermal energy

Location

The biggest problem holding us back from worldwide geothermal deployment is finding suitable sites for their construction. The basic requirements of suitable sites include heat, fluids (water or steam) and, most importantly, fractured permeable rock.

We can always find geothermal heat if we drill deep enough, and we can almost always find a suitable source of water to pump into the reservoir, including waste water from nearby towns, but permeability is a challenge.

There are only a few accessible places on earth where traditional geothermal is feasible, so, it would seem that most of that vast amount of energy below the ground is out of our reach.

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For example, in the US, the country’s Eastern coast is practically devoid of geothermal potential with current technology.

Costs

The second big obstacle is cost. The process of exploration, drilling into the ground, building a power plant and generating power is very expensive.

These costs drive geothermal’s average levelized cost of electricity generation or LCOE to the range of $0.04 to $0.14 per kilowatt-hour [9], making it more expensive than onshore wind ($0.033/kWh) and utility-scale solar ($0.048/kWh) [10].

Seismicity

Last but not least, there’s a proven connection between pumping water through injection wells at geothermal sites and low-magnitude seismic activity in the region.

While these tremors are no stronger than 3.0 on the Richter scale, it’s definitely something that scares the wits out of local residents and that generates pushback from local communities.

So, there you have it. We’ve finally uncovered the answer to why there aren’t geothermal power plants everywhere.

With our current technology, we can’t build them anywhere, they’re crazy expensive to build, they don’t represent an attractive option for investors, and it scares the locals.

Does that mean it’s the end for geothermal energy?

Of course not! I wouldn’t be covering it if it was!

New technologies to harness geothermal energy

There are at least two promising new technologies that could completely change the game for geothermal energy, one of which already hit commercial scale. They both aim to solve geothermal’s biggest problem: the need for fractured permeable rock.

Enhanced Geothermal Systems (EGS)

The first technology is called Enhanced Geothermal Systems, or EGS. An EGS is a geothermal power plant that artificially creates the much-needed porosity within the earth to allow water to flow from an injection well to the production well.

This is done by pumping cold water into the hot solid rock causing the rock to crack because of thermal contraction and water vapor pressure.

Now, before you shout out in the comments talking about how this is just like fracking, know that EGS only pumps water, so there’s no risk of groundwater contamination, and at much lower pressure, so there’s less risk to the site’s geological stability.

Still, the slight risk of geologic instability is the tradeoff of having access to geothermal energy ANYWHERE, which is HUGE. There are several EGS plants already in commercial operation with France’s Soultz plant and Germany’s Landau plant being the first.

Advanced Geothermal Systems (AGS)

Ok, but let’s say that you’re unconvinced and still a bit more than skeptical about EGS. I have an even better solution for you. An Albert-based technology company called Eavor™ designed the perfect solution for geothermal [11].

Their Advanced Geothermal System or AGS basically works by connecting the injection well to the production well through a sealed pipe, completely eliminating the need for fractured rock.

There are also absolutely no greenhouse gas emissions, no chance of underground water pollution and we can even use liquids other than water to extract heat more efficiently, which is not an option for other geothermal systems.

The first Eavor-loop was built in Canada as a proof of concept in one of the toughest rocks to drill, and has been in operation since 2019.

However, this promising solution is yet to hit commercial scale. If it does, though, it could finally open the door to an endless supply of energy like we’ve never seen before.

Speaking of which, there’s an even newer technology right around the corner that could make Geothermal even more promising, by allowing us to drill twice as deep and access temperatures as high as 1,000 °F (over 500 °C) and get this: without even touching the rock! That breakthrough earned a video of its own so stay tuned for a followup to this video very soon.

If we can get this to work and lower the cost of geothermal electricity down to the levels of current diesel and natural gas generators, we’ll finally have a real candidate to replace fossil fuels on a global scale, and that’s something worth looking forward to!

But I want to hear your thoughts on this. Do you think technologies like enhanced geothermal are simply too risky to pursue? Do you think Advanced Geothermals like Eavor’s solution will be the holy grail of clean, safe, sustainable and reliable energy production? Shout out in the comments section below and don’t forget to check out that video I suggested about residential geothermal heat pumps. As always, thanks for watching!