Geothermal energy is heat harvested from the Earth’s core. Conventional geothermal power generation relies on specific, naturally occurring hydrothermal reservoirs where hot water or steam rises close to the surface, typically near tectonic plate boundaries. The current global use of this resource is limited by this geographical necessity, restricting deployment to a small fraction of the world’s landmass. The outlook for future geothermal energy sources focuses on emerging technologies designed to move beyond these geological constraints. This technological shift aims to transform geothermal from a niche local resource into a globally viable, foundational power source by unlocking the Earth’s widespread heat potential almost anywhere.
New Methods for Harnessing Earth’s Heat
The next generation of geothermal technology involves innovations that engineer the subsurface to extract heat from non-traditional locations. One primary method is the Enhanced Geothermal System (EGS), which targets deep, hot dry rock formations that naturally lack fluid or permeability. The EGS process involves injecting fluid, usually water, deep underground at controlled pressures to create or re-open a network of tiny fractures in the hot rock. This process, known as hydroshearing, creates an artificial reservoir that allows the circulating fluid to absorb the rock’s heat before generating power at the surface.
This technique allows for geothermal power generation in areas previously considered unsuitable, potentially increasing the exploitable resource base tenfold. While EGS shares similarities with hydraulic fracturing, it uses moderate pressures to create small, interconnected cracks for heat transfer and generally uses only water. However, the use of subsurface stimulation requires meticulous site selection and monitoring to mitigate the risk of inducing minor seismic events. EGS projects require deep drilling, often between three and five kilometers, to reach commercially viable temperatures.
An alternative approach is the development of Closed-Loop Systems, often termed Advanced Geothermal Systems (AGS). These systems function like sealed U-tube heat exchangers embedded deep in the hot rock. A working fluid is continuously circulated through a closed pipe system, absorbing heat via conduction from the surrounding rock. Because the fluid is contained within the pipes, AGS eliminates concerns of induced seismicity and water management.
The closed-loop design also reduces the risk of corrosion and scaling common in traditional systems. While the heat extraction rate from a single closed-loop well is lower than a fracture-based system, the technology can be deployed almost anywhere with sufficient heat at depth.
Supercritical Geothermal
Researchers are also exploring Supercritical Geothermal, which taps into extremely hot reservoirs. Here, water reaches a supercritical state above 374°C and 221 bars of pressure. In this state, the fluid acts as neither a liquid nor a gas, possessing a dramatically higher energy content. This can yield five to ten times more power per well than conventional systems.
Global Expansion and Resource Availability
The advancements in EGS and closed-loop systems fundamentally shift geothermal’s potential market size. By creating artificial reservoirs or using sealed boreholes, these methods eliminate the need for naturally occurring permeable rock and hot water. This expansion means next-generation geothermal can be pursued in over 90% of the globe, transforming it into a widespread, accessible option. The full technical potential of these systems is considered second only to solar energy in terms of global resource availability.
The lifting of geographical limitations is coupled with economic drivers that promise to make geothermal cost-competitive with other renewables. Drilling technology for deep geothermal projects is being adapted from the mature oil and gas industry, leading to advancements in speed and efficiency. Increased standardization and drilling improvements are projected to drive down the Levelized Cost of Electricity (LCOE) for next-generation projects. Some projections suggest costs could fall by as much as 80% by 2035, potentially reaching around $50 per megawatt-hour.
At this cost level, geothermal would be highly competitive with other low-emissions dispatchable sources like hydro and nuclear, and competitive with solar and wind paired with battery storage. Such cost reductions are expected to spur massive investment, potentially reaching $2.5 trillion by 2050, resulting in an estimated 800 GW of global power capacity. This expansion is not limited to electricity generation, as the vast heat resource can be used directly for industrial processes, district heating, and agricultural applications.
Geothermal’s Role as Reliable Baseload Power
The future value of expanded geothermal capacity lies in its unique ability to provide continuous, high-output power to the electrical grid. Unlike intermittent solar and wind power, geothermal plants operate consistently throughout the day and year, giving them a high capacity factor. In 2023, global geothermal capacity had a utilization rate over 75%, significantly higher than typical rates for wind (less than 30%) or solar (less than 15%).
This characteristic makes geothermal power an invaluable source of baseload power. As electrical grids integrate increasing amounts of variable renewable energy from solar and wind, the need for stable baseload sources to maintain grid balance becomes more pressing. Geothermal plants provide this stability, ensuring that power demand can be met even when intermittent sources are unavailable.
Future geothermal plants are expected to play a more flexible and dynamic role in grid management. Newer designs are being developed that can operate flexibly, adjusting their output as needed to support the integration of intermittent sources. This potential for flexible output, or dispatchability, means geothermal facilities could stabilize the grid by ramping production up or down. Furthermore, underground thermal resources could be utilized as large-scale thermal batteries, storing heat until needed for power generation.