A new era in renewable energy: Incredible drilling technology promises to revolutionize geothermal energy, reaching 20 km deep to extract 10 times more energy

The crazy plan to extract 10 times more energy from super-hot rocks at 373 degrees: a millimeter-wave driller

When we think about renewable and sustainable energy, we usually think about wind energy and, especially, solar energy. The latter is the one who is starring in a increased demand for photovoltaic panels due to China's efforts to undercut competition by selling its cards at prices below cost (something that already has consequences for companies). However, it is also important to remember that a good asset for decarbonization is geothermal energy.

There is a company that wants to dig wells more than ten kilometers deep to take advantage of the heat in the ground. He already has several projects in mind, but the problem is that it is a puzzle of considerable dimensions.

Geothermal Energy: The Power of Earth's Heat

Geothermal energy consists of harnessing the Earth's natural heat. Digging to a great depth, geothermal plants can generate electricity in a continuous and stable manner 24 hours a day, 365 days a year, as it does not depend on water currents, the Sun, or gusts of wind. It is very efficient energy and, although the initial investment is high, the operational and maintenance cost is low.

It is not perfect, as geothermal resources are not available everywhere and implies a risk as it could cause geological instability. Furthermore, although it is cleaner than energy sources that involve fossil fuels and does not emit greenhouse gases, when digging, gases and minerals can be released that can contaminate the subsoil.

A superwell. It is, however, an energy source that is attracting attention due to this unlimited flow and the fact that it can produce energy regardless of the weather situation. In 2006, an MIT research group claimed that by harnessing just 2% of the geothermal energy stored in rocks at a depth of between three and ten kilometers, it could provide more than 2.000 times the annual energy consumption of the United States.

A company called Queme Energy wants to go all in on geothermal. It was born from research projects at MIT and, two years ago, surprised by presenting a drilling system that, according to them, allowed digging to a greater depth than anything we have used so far. Considering that the deepest hole excavated is 12 kilometers, its technology would allow it to reach up to 20 kilometers.

Superhot Rocks and Advanced Drills

super hot rocks. One of the keys to geothermal energy is digging as much as possible. This way, as we go deeper and deeper into the Earth, there will be more heat and it will be possible to extract a greater amount of energy. Furthermore, by digging deeper, what Queme wants to achieve is that we can create geothermal energy plants anywhere, not just in the most indicated spaces (like active tectonic faults).

This way, and with the company's calculations, we will reach areas where the temperature is up to 450º Celsius. Trenton Cladouhos, Vice President of Geothermal Resource Development at Quale Energy, commented that “if we really want geothermal energy to be a step-changer, we have to operate at super-hot temperatures in excess of 375ºC.”

Three models. The company showed its intentions two years ago, but hadn't really shown its model... until now. In a recent statement, Queme presented three concepts for geothermal systems with three very different approaches in execution and effectiveness, with 'permeability clouds' being the most ambitious and the one they want to develop.

The first of them is a closed circuit that would work like a boiler: cold water is injected, which, due to the 170ºC temperature underground, heats up and rises in the form of hot water to the surface. Once there, steam techniques from geothermal plants can be applied. The second model is that of flat hydraulic fractures through which water is injected at high pressure into a well, it heats up at the bottom when creating great pressure and is extracted. And, finally, the Queme model, that of permeability clouds.

Revolutionizing geothermal. This model shows the formation of microscopic cracks that create a so-called permeability cloud around the rocks. By digging at great depth using millimeter waves, cold water would be injected, which would generate these microfractures in the hot rock and exit through another well in the form of steam.

According to their simulations, “a superhot system can provide five to ten times more energy than is normally produced from conventional systems.”

The challenge. The problem is… we haven't had contact with these depths and we don't know how the rocks will react. Cladouhos comments that water filtered through these wells would become supercritical. “This steam-like phase carries between 3 and 4 times more energy than normal hot water and, when piped to turbines on the surface, is converted into electricity with an efficiency of between two and three times greater.”

The problem is twofold. The first is simply to reach that depth. Current drills are not designed to withstand either the temperatures or the extreme pressures that occur at these depths. Quale is working on a new millimeter wave drill to melt and vaporize rock. The second challenge is, directly, extracting the heat. There are some very resistant underground radiator systems or heat exchangers, but none have worked at temperatures above 200ºC.

Test volcano. Furthermore, the company points out that we know very little about what happens when a super-hot rock located at great depth is exposed to cold water pumped at high pressures. Therefore, they will develop field tests using the Newberry volcano in central Oregon as a vehicle to prove their model. It's something they will do in 2025 or 2026, and they say their permeability cloud plan may not be the only approach.

In fact, they point to the coexistence of hybrid techniques such as plane fractures, natural fractures and microfractures of the most ambitious model in order to harness all possible energy.