Drilling deeper and hotter: that is, according to Quaise Energy and its CEO Carlos Araque, the key to the future of deep geothermal energy. From the United States to Europe via Switzerland, geothermal initiatives are multiplying, driven by new technological advances.
On September 4th, in a quarry located near Marble Falls, Texas, the young company Quaise Energy achieved a true technological feat. Its engineers demonstrated the effectiveness of an innovative process: the use of a concentrated energy beam capable of transforming rock into mineral vapor. Thanks to a gyrotron — a device emitting millimeter waves — integrated into the center of the drill bit, they succeeded in melting the rock by bombarding it with high-frequency waves. Result: 118 meters of granite drilled with remarkable precision, as evidenced by the smooth, polished walls of the borehole during this operation.
Added to this feat is an unprecedented drilling speed. Quaise Energy's teams recorded penetration rates reaching five meters per hour in granite — nearly fifty times faster than conventional methods. And this is just the beginning: during previous tests, the company had already reached a record speed of twelve meters per hour, suggesting considerable room for improvement.
But perfecting the technique is only a means, not an end in itself for Quaise Energy. Its objective remains very clear: to revolutionize deep geothermal energy. According to its CEO, Carlos Araque, the company intends to drill to great depths to capture the heat of the Earth's subsurface and turn this nearly inexhaustible resource into a sustainable pillar of the global energy transition.
“Our analysis shows that the growth of geothermal energy could generate $1 trillion in investments by 2035,” explains Fatih Birol, executive director of the International Energy Agency (IEA).
At a time when the planet is going through a critical phase climatically, exploiting the heat buried in the Earth's interior increasingly appears unavoidable. From the United States to Europe and Switzerland, geothermal initiatives are multiplying, driven by new technological advances.
“New technologies are opening up new horizons for geothermal energy around the world, offering the possibility of safely and cleanly meeting a significant share of the rapidly growing global demand for electricity. Our analysis shows that the growth of geothermal energy could generate $1 trillion in investments by 2035,” said Fatih Birol, executive director of the International Energy Agency (IEA).
“In Switzerland, generally speaking, the temperature in the ground increases by about 30°C per kilometer of depth. The temperature at 5,000 meters deep is around 160°C,” says the Federal Office of Energy (FOEN). It is precisely this heat that the company SwissDGS aims to exploit.
Founded last year by EAPOSYS, in partnership with the Amberg and Basler & Hofmann groups, the company is developing an innovative approach called AGS (Advanced Geothermal Systems), as opposed to the more traditional methods based on hydraulic fracturing (fracking). “These AGS systems consist of collecting heat simply by circulating water in deep deviated wells connected to each other at depth, like an inverted radiator. There is therefore no overpressurization of the formation, which eliminates the risk of inducing earthquakes,” explained Naomi Vouillamoz, co-founder of EAPOSYS, in our pages.
A few days ago, EAPOSYS announced the signing of an agreement with Halliburton to carry out a subsurface feasibility study aimed at accelerating the deployment of AGS systems. “This study will contribute to the industrialization of EAPOSYS's well engineering and design, while integrating geothermal and stratigraphic considerations specific to the sites in order to minimize drilling risks and optimize the evolutionary design of the wells,” the company said in a statement.
Whatever technology is used or whatever depth is targeted, one thing is now certain: geothermal energy intends to exploit the abundant heat of the Earth's interior to support the energy transition. O.W.
In its report titled “The future of geothermal energy,” the IEA estimates that this energy source could cover up to 15% of the growth in global electricity demand by 2050, provided development costs continue to fall. “Such an expansion would represent the deployment of nearly 800 gigawatts of geothermal capacity worldwide — equivalent to annual generation today of the combined electricity demand of the United States and India.”
This potential is naturally being watched closely in Switzerland. “Our country has very significant geothermal potential. The prospects offered by this clean, inexhaustible and constant energy source are attractive,” says the Federal Office of Energy. A view shared by Patrick Scherrer, president and co-founder of EAPOSYS, who believes that unconventional deep geothermal — notably EGS (Enhanced Geothermal Systems) and AGS (Advanced Geothermal Systems) — holds colossal potential: “The vast majority of the heat beneath our feet, about 99%, is stored in the rock, compared with only 1% in conventional geothermal resources.”
Just a few kilometers below the Earth's surface, temperatures reach between 400 and 500 °C. Thanks to recent technological advances, it is now possible to convert this heat into electricity, thus providing access to clean, local energy available continuously. Yet, despite this potential, deep geothermal remains underexploited. According to the latest statistics from the International Energy Agency (IEA), it currently represents only about 1% of global electricity generation.
“If one considers the entire planet, the maximum depth required to exploit geothermal energy would be around 12 miles, or about 19 km,” estimates Carlos Araque, CEO of Quaise Energy.
“The oil industry commonly drills to depths of 3 to 5 kilometers, reaching temperatures of 65 to 93 °C at most. To exploit the appropriate geothermal resource, these depths will have to be doubled, or even tripled,” explained Carlos Araque, CEO of Quaise Energy, in an interview with CNBC.
Drilling deeper and hotter: this is, according to him, the key to the future of deep geothermal. “In Iceland, one can reach the necessary conditions at about 3 miles (i.e. 4.8 km). In New York, one would probably have to drill down to 8 miles (nearly 13 km). If one considers the entire planet, the maximum depth required to exploit geothermal energy would be around 12 miles, or about 19 km. We absolutely want to be able to reach that depth so that the world can have access to geothermal electricity,” he also told Energy Monitor.
In a few years, Quaise Energy thus aims to commission the world's very first “superhot” — or supercritical — geothermal plant, a facility capable of producing near-unlimited energy from the heat of the Earth's subsurface.
Quaise Energy’s ambitions are undeniably promising, but their technology raises as much enthusiasm as questions. Can one really drill to such depths with sufficient efficiency, stability and without risks? At this stage, many questions remain with very few answers.
Patrick Scherrer, co-founder of EAPOSYS, describes a technology with significant disruptive potential. “The main advantage of this approach lies in its non-contact nature, which avoids 'tripping' operations, those repeated pull-outs of the drill bit required in conventional methods when it wears out due to contact with the hard rock found at great depth. This could considerably reduce drilling times and therefore also the associated costs,” he explains.
However, several technical uncertainties remain. “This technology is primarily suited to hard rocks, where conventional mechanical methods reach their limits. Conversely, in the sedimentary cover, conventional approaches will remain essential, notably to ensure casing integrity and to prevent any ingress of fluids or gases that may be present in the layers crossed,” specifies Patrick Scherrer.
Moreover, absorption efficiency is also likely to vary depending on lithology and rock composition, and the stability of the vitrified walls remains to be demonstrated at great depth. As for the management of particles or ash resulting from the ablation process, it represents a major challenge to maintain circulation and the cleanliness of the well.
The use of the gyrotron also presents certain environmental risks. First, the localized release of hot gases or particles could affect surrounding vegetation. A failure of the vitrified lining could also cause contamination of the underground aquifer, requiring particular vigilance during the design and operation of the system. As for waste from refractory metals and cooling liquids, they will need to be treated carefully to avoid any source of pollution.
According to the co-founder of EAPOSYS, these challenges do not diminish the enormous potential of deep geothermal. “Conventional drilling methods already offer considerable potential in Switzerland, at depths of 3,000 to 6,000 meters, notably for heat production. The technological advances under development, such as those of Quaise Energy, open the way to safe local continuous geothermal electricity generation at very competitive costs.”
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