Deep beneath the Earth's crust lies a virtually inexhaustible source of energy. Geothermal power, derived from the planet's internal heat, offers a steady, carbon-free electricity supply, independent of weather or daylight. Yet its potential remains largely untapped, hindered by high upfront costs and geological risks. As the world races to decarbonise, is geothermal poised to become a major player, or will it remain a niche solution?
Unlike solar and wind, geothermal energy is not intermittent. A geothermal plant can run at over 90% capacity factor, providing baseload power comparable to fossil fuels or nuclear. The technology is mature: conventional hydrothermal plants, which tap into natural reservoirs of hot water or steam, have operated for decades in places like Iceland, New Zealand, and the United States. However, these resources are geographically limited to tectonically active regions.
Enter enhanced geothermal systems (EGS), which aim to create artificial reservoirs by fracturing hot, dry rock and injecting water. This could unlock geothermal potential almost anywhere. The U.S. Department of Energy estimates that EGS could provide over 100 gigawatts of capacity by 2050, a significant contribution to the grid. But challenges remain. Drilling to depths of several kilometres is expensive, often accounting for half the project cost. And the process of fracturing rock can induce seismic activity, a concern that has stalled projects in Switzerland and South Korea.
Recent technological advances seek to address these issues. Companies like Fervo Energy are using horizontal drilling and distributed fibre-optic sensing, techniques borrowed from the oil and gas industry, to improve heat extraction and reduce costs. In Nevada, a Fervo pilot project achieved a 70% reduction in drilling time compared to traditional geothermal wells. Meanwhile, startups like Quaise Energy are developing millimetre-wave drilling technology that could vaporise rock, reaching depths of 20 kilometres where temperatures exceed 500 degrees Celsius. Such superhot rock geothermal could produce ten times the power of conventional plants.
But the economic hurdles are steep. The levelised cost of electricity (LCOE) from geothermal ranges from $60 to $100 per megawatt-hour, compared to $30-$40 for onshore wind or solar. Investors are wary of the geological risk: a dry hole can mean a total loss of capital. Government incentives, such as the U.S. Investment Tax Credit for geothermal, help, but more is needed. The European Union's Horizon Europe programme funds research into advanced geothermal systems, and Japan recently announced subsidies for deep geothermal exploration.
Environmental concerns also loom. Geothermal plants can release small amounts of greenhouse gases trapped underground, such as carbon dioxide and hydrogen sulphide, though emissions are minuscule compared to fossil fuels. Water usage is another issue; some plants consume large quantities for cooling, but closed-loop systems can minimise this. Induced seismicity, while typically minor, must be carefully managed through real-time monitoring and traffic-light protocols that halt operations if tremors exceed thresholds.
Despite these obstacles, the case for geothermal is compelling. Unlike nuclear, it offers no risk of meltdown and has a small land footprint. As the world phases out coal and gas, geothermal could provide the grid stability that renewables alone cannot. The International Energy Agency projects that geothermal could meet 3-5% of global electricity demand by 2050, up from less than 1% today. With the right policies and technological breakthroughs, that figure could be higher.
The urgency is palpable. We are in a race against time, and we need every tool at our disposal. Geothermal may not be the hero of the energy transition, but it could be a crucial supporting actor. The heat is there, waiting. We just have to find a way to tap it economically and safely.
