With emerging technologies and techniques, heaps of deep underground heat can be harnessed as a constant, reliable source of electricity around the world.

The geothermal energy sector has been a solid provider of clean, baseload electricity worldwide for over a century. Today, despite its proven track record, with 16 GW installed globally, geothermal only accounts for 0.5% of the world's total installed renewable electricity capacity. This limited penetration can be attributed to the geographical constraints of geothermal energy, which requires specific underground conditions—a trifecta of Heat, Water, and Porosity.

The technology required to access this energy source requires tapping into the heat emanating from sedimentary and volcanic rocks lying at depths of up to 3 km beneath the Earth's crust, where temperatures can reach up to 250°C.

That’s hot, but what if wells were drilled deeper and better to tap into even hotter and conductive rocks?

Alejandro Solé, Chief Investment Officer at TechEnergy Ventures, from Tecpetrol’s energy transition division, discussed this issue and the challenges involved at CERAWeek by S&P Global, an energy conference in Houston.

“The discussion today is about the next step, it’s about progress, it’s about terawatt, it’s about having a massive impact on the decarbonization of the world,” he said. “Geothermal 2.0 is the opportunity to reach higher temperatures, lower the cost, enter factory mode, and deliver highly competitive costs. Geothermal 3.0 is how we get to 500 degrees, how we reach supercritical depths, and how we start developing wells that have 50 MW per well.”

The answer is that the potential is huge. If you go 10 km below ground, the so-called supercritical steam of 500°C is available in 70% of the Earth, while at 20 km down, it’s everywhere. Harnessing this would massify a reliable source of clean energy that is now limited by the location of shallower heat sources in more permeable rocks

How deep (hot) do we need to go?

Logic tells us that we should go deep enough to be able to reach 500°C at the surface and thus unlock supercritical steam conditions; this could deliver 4-10x the enthalpy than, say, 200°C steam. But while this is the case, the challenges of drilling deeper and hotter with today´s technology are also exponential.

“Incredible progress is happening with geothermal technology that we could call 2.0,” Solé said in his presentation on March 19 during the conference. “This is reflected by the latest Department of Energy (DOE) take-off plan which includes the ambition of reaching 90GW of baseload power, it shows that progress is real with companies like Fervo now entering well construction Factory mode”

Geothermal 2.0 means going as deep as 200-300°C (3-5 km), with existing/upgraded technologies focusing on improving drilling performances.

The U.S. Department of Energy’s Frontier Observatory for Research in Geothermal Energy, (FORGE), is developing new drilling and stimulation techniques to make it commercially viable to drill to depths of up to 5 km at a large scale. They’re testing enhanced geothermal stimulation techniques to make it easier to reach and improve permeability in reservoir rock that’s harder to penetrate that far down.

Solé said that this was just the first step, as even more should be done to scale up geothermal to the terawatt scale.

Techint Group, the parent company of TechEnergy Ventures, is supporting these efforts with investment, technical support and business development, drawing on the knowledge from its different units in engineering and construction, steelmaking, and the production of oil and gas.

Start-ups will play an important role as well. Two of them, both supported by TechEnergy Ventures, joined Solé in the presentation.

Carlos Araque, CEO of Quaise Energy, explained how his firm is developing drilling technology that uses millimeter-wave electromagnetic beams for ultra-deep drilling at lower costs to harness the heat at depths of between 10 km and 20 km.

He emphasized the need to achieve geothermal heat grades consistent with existing generation and industrial infrastructure currently running on fossil fuels.

“We live in a world powered by steam,” Araque said. “We have terawatts of power plants that are all steam driven, and we have terawatts of heat-based processes. Imagine if you were able to take any single one of those and convert it by accessing steam at the right heat temperature. If we can reach 300 to 500°C, consistent with that fossil-fuel fired infrastructure, we can access that temperature at 5 km down in about 5% to 10% of the world. By the time we get to 10 km, we are at 50% of the world population, and by the time we are at 15 to 20 km, we can have pretty much all of humanity on geothermal.”

Paris Smalls, CEO of Eden GeoPower, shared how his Massachusetts-based start-up is developing groundbreaking electro-hydraulic fracturing technology to increase fluid permeability to harvest heat more efficiently from rock formations by mitigating the fluid short-circuiting that has long hampered geothermal well productivity.

Smalls said the fracking methods for developing oil and natural gas from shale formations are not the best option for geothermal because of the hotter and different kinds of rocks—mostly granite—that lie farther underground. Instead of pumping in large amounts of water to create fracks, Eden uses high-voltage electricity to minimize water injection and make fracking more effective.

“Once we can figure out how to get deep into these reservoirs and better stimulate them so that you can start maximizing the heat harvested from them, we’ll make a lot of progress in reaching this supercritical state of geothermal production.”

These are the advances needed to develop the vast stores of deep, underground, accessible heat to make geothermal a driver of the energy transition to net-zero greenhouse gas emissions. We believe that this is what’s needed to see our Geothermal 3.0 grow to terawatt scale.

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