CLEAN, LIMITLESS ENERGY
The planet is already hot. The question is whether we can turn that fact into power.
A Fieldbook for founders and investors | 9 September 2026
A first-person opportunity narrative, checked against technical and project evidence.
I think the next great energy company might begin with a question a teenager can ask: if Earth is hot underneath our feet all the time, why do we still burn things to keep the lights on?
01 · The thing beneath us
THE HEAT BELOW
Earth constantly leaks heat from its inside. Scientists estimate that flow at 47 +/- 2 terawatts. A terawatt is one trillion watts. All of humanity’s energy use in 2024 averaged about 19 terawatts. Davies & Davies Energy Institute
That does not mean we can catch all that heat. Most of it is spread too thinly, too deep, or in the wrong kind of rock. It does mean that the planet is not running out of energy. Our problem is learning how to collect a small, useful share of it without spending more than it is worth.
The IEA has modelled what could happen if better drilling lets us reach much deeper hot rock. In that thought experiment, geothermal could produce enough electricity to meet today’s global demand around 140 times over. This is not a reserve count, a forecast, or a promise. It is a measure of how large the physical prize could be. IEA
I call that “limitless” only in the everyday sense: big enough that the limit is our ability to use it, not the amount of heat below us.
02 · The energy we still cannot buy
POWER, WHEN YOU NEED IT
Electricity is useful because it can become almost anything: light, cooling, motion, industrial heat, computer work, and the work done by machines.
But a grid has a simple rule. A hospital, factory, train system, or data centre needs electricity at midnight and during a heat wave. It cannot wait for a sunny or windy day.
Solar and wind are essential and should keep growing. Their output changes with sunlight and weather. Batteries help by saving electricity made earlier and using it later. They do not make new energy. Gas plants can run whenever we ask them to, but they burn fuel. Nuclear plants can also run for long stretches, but are difficult to build quickly and cheaply in many places.
Geothermal can make low-carbon electricity day and night because the heat underground does not wait for the weather. Existing geothermal plants ran, on average, for more than three quarters of their possible operating time in 2023. IEA
That is the product I care about: clean electricity that is there when people need it.
03 · The broken status quo
A POWER PLANT, UPSIDE DOWN
The basic machine is easy to picture. Drill down to hot rock. Send water or another working fluid down one hole. Let it pick up heat. Bring it back through another hole. Use the heat to make electricity.
The difficult part is that nature rarely gives us all the pieces in one place. Traditional geothermal works best where hot rock, water, and tiny connected gaps in the rock already meet at a depth we can afford to reach. Those places exist, but they are uncommon.
Engineers are trying two ways around that limit. One is to create or improve the tiny cracks that let water move through hot rock. That is called an enhanced geothermal system, or EGS. The other is to go much deeper, to much hotter rock. That is the superhot-rock idea.
So what happens to the water down there?
At about 374 C and 22.1 MPa, pure water reaches its critical point. Below that boundary, liquid water can boil and become steam: there is a visible dividing line between the two. Above it, that dividing line disappears. There is only one phase, called a supercritical fluid. It does not form bubbles or boil in the ordinary sense. The Iceland Deep Drilling Project
That strange state is part of the prize. Under the right pressure, this fluid can remain denser than ordinary geothermal steam while carrying a great deal of energy in every kilogram. A well can therefore bring more heat to the surface without moving proportionally more fluid. But its properties change sharply near the critical point: a modest change in pressure or temperature can produce a large change in density and in how the fluid transfers heat. Multiphase flow modelling study
And the fluid underground is not pure water. It may contain salt, acid, and gases, which shift its phase boundaries and determine what happens as it rises and loses pressure. Minerals can drop out and clog the path; acidic liquid can condense and attack the well lining. Iceland’s IDDP-1 well reached roughly 440 C, but also showed how these chemical effects can damage the hardware meant to contain the resource. IDDP-1 fluid study
The heat is common. A long-lived underground plumbing system is not.
04 · Why now
THE DOOR IS OPENING
Three things make this worth trying now.
First, geothermal teams are getting better at drilling the way oil-and-gas teams do: long wells, precise steering, and constant measurement. Fervo has already made commercial electricity from an engineered geothermal system at Project Red and is building its larger Cape Station project. That proves real progress. It does not prove that very hot rock can supply cheap power for decades. Fervo prospectus
Second, Quaise is testing a different way to cut rock. Instead of pushing a mechanical drill bit into the hottest rock, it sends very high-frequency electromagnetic energy down a ridged metal tube. Think of it as a far more powerful and much more precise cousin of microwave heating. It is a real drilling advance. It has not yet proved a deep, long-lasting power well. Quaise
Third, many grids now badly need clean electricity that can run day and night. Old coal and gas sites can offer useful connections to the grid, land, water systems, and trained workers. Good infrastructure cannot fix bad rock. But it can make a good site much more valuable.
I do not think this is solved. I think the tools are good enough to finally ask the right question in the field.
05 · The wedge
BUILD THE PROOF FIRST
I would not start a company whose pitch is simply “we drill deeper.” I would start a company that proves, step by step, whether one site can make clean electricity people can count on.
Its first job is to find an unusually good place: enough heat, the right kind of rock, a workable water plan, a path to permits, a connection to the grid, and partners who understand the local geology.
Its second job is to build the underground system and measure everything. Can we reach the heat? Can water move through the rock and come back hot? Do the holes, pipes, sensors, and materials keep working? Can the result last long enough to pay for itself?
The first buyer is not “the whole world.” It is a utility, industrial company, or owner of an old thermal power site with a concrete need for reliable clean electricity.
A good early test has a hidden advantage: it can tell me to stop before I spend the money for a power plant. That is not failure. It is the company doing its job.
06 · How the first system works
GETTING THERE IS ONLY HALF
Quaise’s idea is interesting because it changes the last part of drilling. A machine on the surface makes very high-frequency energy. A ridged metal tube carries that energy down the hole. At the bottom, the rock can crack and flake into small pieces instead of forcing a metal drill bit to grind against the hottest rock.
Then the hard work starts.
Gas must carry those rock pieces and vapor back up without clogging the hole. The energy must still be strong after travelling kilometres. Melted rock may make a glass-like coating on the hole wall, but that coating is not proven to be a safe replacement for steel casing. The hole must turn toward the right rock. The sensors must keep working in heat that destroys ordinary electronics.
I also see two ideas worth testing in the lab, not selling in a pitch deck. One puts the energy-making machine near the bottom of the hole, which could reduce losses on the way down. The other uses sound waves to keep rock dust moving. Both could help. Both could easily fail under real heat, pressure, vibration, and tight space.
Reaching hot rock is not the same thing as making electricity from it.
07 · The proof before a power plant
HOT IS NOT ENOUGH
One very hot hole in the ground is exciting. It is not a power business.
I need a loop. Fluid goes down, flows through hot rock, picks up heat, and comes back up at a useful temperature and rate. That loop must keep working for years, not minutes.
This is where the rock fights back. Deep rock can slowly squeeze shut the cracks we need. Water can leak away. Water can take the shortest route through the rock and come back before it is hot enough. Minerals can build up inside pipes. Hot salty water can corrode metal. Changing pressures underground can trigger small earthquakes. The materials have to survive all of that.
The Iceland Deep Drilling Project showed both why this is exciting and why it is hard: it reached extreme conditions, but also faced damaged pipes, lost fluid, and materials problems. IDDP
Before I would fund a power plant, I need four answers: can we reach the heat, move enough fluid, keep the loop working, and do it cheaply enough to beat the alternatives?
08 · The path of attack
MAKE THE NUMBERS WORK
The goal is not the hottest measurement on a slide. The goal is clean electricity at a price a buyer will sign up for.
I would begin with the site. Measure the heat, the rock, the water, the chemical risks, the permits, and the grid connection. If there is no believable path to a working loop, stop.
Next, drill one test hole and measure the real cost of reaching the target: time, energy, lost material, damaged casing, and lost signal from the sensors. If we cannot reach the heat safely and predictably, stop.
Then build and test the water loop. Measure how hot it is, how much fluid comes back, how quickly it weakens, and whether scaling, corrosion, or earthquakes make it unsafe or too expensive. If it cannot last, stop.
Only after those tests would I build a power plant and ask big infrastructure investors to fund it. Fervo’s $421M Cape Station financing shows that lenders will fund better-understood geothermal projects. It does not mean lenders have already accepted first-of-a-kind superhot risk. Fervo financing
09 · Why this company can win
LEARNING BEATS HYPE
Fervo shows that modern geothermal drilling can work. Quaise is testing a new way to reach deeper rock. Mazama and the Newberry test site are helping the field understand very hot rock. Many companies, universities, and suppliers will build important pieces.
I do not think one winner has to own every tool. I think the winner has to learn fastest from the real world.
Every hole teaches us more about the rock. Every water test teaches us which cracks stay open, which materials fail, and which sites are worth another dollar. Every good site makes choosing the next one less of a guess.
Over time, that learning can become hard to copy: rights to the best sites, data from real wells, practical knowledge of materials, trusted local partners, and a track record of knowing when to go and when to stop.
In this business, the field is where you learn how to build the factory. The field becomes the factory.
10 · The founder decision
EARN THE RIGHT TO SCALE
This opportunity excites me because the resource is huge and the useful product is rare. The heat below us does not need fuel trucks, sunshine, or wind. We just do not yet know how to turn it into repeatable, affordable electricity at the places that matter.
That is the company.
I would pursue it only with an exceptional site, people who understand drilling, underground rock, high-temperature materials, and power projects, and investors who accept that a careful no can be a valuable result.
I would walk away if drilling damages the well too badly; if the underground water loop cannot carry enough heat; if chemical problems or earthquakes make it unsafe; or if the cost stays too high even when the science works.
The near-term ambition is one site and one loop that lasts. The long-term ambition is much larger: clean electricity is there when people need it, in far more places than it is today.
I do not need geothermal to be literally limitless to believe it may be one of the most important energy sources we learn to use.