Enhanced Geothermal Systems (EGS) could soon make clean energy from Earth’s natural heat cost-competitive with grid power, potentially revolutionising the energy landscape by 2027
The quest for reliable, clean energy may soon find a powerful ally beneath our feet. Researchers at Stanford University have revealed that enhanced geothermal systems (EGS), which harness the Earth’s natural underground heat, could become cost-competitive with traditional grid power by 2027.
This breakthrough, driven by advancements in drilling technology and a deeper understanding of subsurface dynamics, promises to unlock a vast, untapped energy resource. However, the potential for induced seismicity requires careful mitigation strategies to ensure the safe and sustainable deployment of this technology.
Overcoming location limitations: The rise of EGS
Historically, geothermal energy production has been confined to regions with specific geological characteristics: volcanic activity, permeable rocks, and abundant underground fluids. This limited its application to a handful of locations worldwide. However, the development of EGS, a technique adapted from the oil and gas industry, has dramatically expanded the potential reach of geothermal power.
EGS involves injecting fluids at high pressure into deep rock formations to create or enhance fractures, allowing hot water to be extracted and used to generate electricity.
“There is a lot of excitement about enhanced geothermal energy,” states Roland Horne, a professor of energy science and engineering at Stanford, highlighting the growing global interest in this technology.
Drilling innovations drive down costs
A key factor in the projected cost reduction of enhanced geothermal systems is the adoption of advanced drilling techniques. Innovations from the shale gas boom, such as horizontal drilling and hydraulic fracturing, have been adapted to improve efficiency and reduce costs. The use of synthetic diamond drill bits has also significantly accelerated drilling times, enabling the completion of wells in weeks rather than months.
“Drilling faster makes an enormous difference to the whole economics of EGS,” emphasizes Horne. These advancements, combined with the ability to drill multiple wells from a single pad, are driving down the capital expenditure associated with EGS projects.
Economic viability and grid integration
Modelling conducted by Horne and his colleagues suggests that these technological advancements could make EGS cost-competitive with average electricity prices in the United States by 2027, at approximately $80 per megawatt-hour. In California, a state already leveraging geothermal energy, enhanced geothermal systems could potentially increase capacity tenfold by 2045, reaching 40 gigawatts.
This significant expansion would not only replace fossil fuel-based baseload power but also provide a stable, reliable energy source to complement the intermittent nature of solar and wind power. “With EGS, we can meet the load,” Horne explains, underscoring the potential for geothermal to play a pivotal role in a decarbonised energy grid.
Addressing seismic risks: A prudent approach
While EGS offers immense potential, the risk of induced seismicity remains a crucial concern. Fracturing deep rocks to access geothermal reservoirs can trigger earthquakes, necessitating careful mitigation strategies. One fundamental approach is to avoid drilling in seismically active areas. Beyond location selection, implementing a robust monitoring system, known as a traffic-light protocol, is essential. This system involves slowing down or halting drilling operations based on the magnitude of seismic events.
Furthermore, a novel strategy for minimising seismicity involves creating numerous smaller fractures rather than a few large ones. This “drip-drip-drip” approach, as Horne describes it, reduces the likelihood of activating existing faults and triggering larger earthquakes. “A drip-drip-drip instead of a fire hose approach can significantly reduce the risk and size of induced seismicity,” he asserts.
A game changer for clean energy
The potential of enhanced geothermal systems to provide a reliable and sustainable energy source is undeniable. By overcoming the limitations of conventional geothermal systems and addressing the associated risks, EGS could revolutionise the global energy landscape. The research conducted at Stanford University provides a roadmap for the safe and efficient deployment of this technology.
“EGS could be a game changer for green energy production not just in California but across the U.S. and worldwide,” Horne concludes. “Safely harnessing Earth’s internal heat could substantially contribute to powering our future.” As the world transitions towards a cleaner energy future, enhanced geothermal systems stands poised to play a pivotal role in meeting the growing demand for reliable and sustainable power.
