The Baseload Renewable That Nobody Talks About
The energy transition conversation has been dominated by solar, wind, and battery storage for the better part of a decade. The cost trajectories of solar photovoltaic and onshore wind have been compelling: costs have fallen by ninety percent and seventy percent respectively over the past fifteen years, making them the lowest-cost sources of new electricity generation in most markets and the obvious first choice for the decarbonisation investment that climate commitments and energy security concerns are driving. This cost success is real and commercially important. It is also incomplete as an energy transition strategy because the variable generation profile of solar and wind creates the reliability challenge that battery storage at current costs and energy densities cannot fully address for industrial-scale power systems that need continuous supply. Geothermal energy generates electricity continuously, around the clock, from the heat stored within the earth. It produces zero direct emissions during operation. Its capacity factor, the proportion of its installed capacity that it delivers as electricity, typically exceeds ninety percent, compared with twenty-five to thirty-five percent for solar and wind in most locations. It occupies a small physical footprint relative to the power it produces and has no fuel cost because the heat source is inexhaustible on any commercially relevant timescale. And it has been almost entirely absent from the energy transition conversation, the policy frameworks, and the private investment flows that have transformed solar and wind over the past decade.
The reason geothermal energy has been marginalised in the energy transition is not that the technology does not work. Iceland generates the majority of its electricity from geothermal. Kenya derives over forty percent of its electricity from geothermal plants. The Philippines, El Salvador, and New Zealand all have substantial geothermal power industries. The constraint has been geographic. Conventional geothermal power development requires hydrothermal resources, naturally occurring combinations of heat, water, and permeability at accessible depths, that exist only in specific geological settings associated with volcanic activity, tectonic boundaries, and other geological features that limit commercially viable conventional geothermal to a small proportion of the earth's land surface. The technology development that is changing geothermal's commercial potential is the extension of geothermal beyond these restricted geological settings through enhanced geothermal systems that create the subsurface permeability that conventional geothermal requires naturally.
Enhanced Geothermal Systems and the Technology Inflection
Enhanced geothermal systems drill into hot dry rock formations that lack the natural permeability to circulate water, then create that permeability artificially through hydraulic stimulation techniques borrowed from the oil and gas industry. Water is injected under pressure to create a network of fractures in the hot rock, circulated through the fracture network where it absorbs heat from the rock, returned to the surface at high temperature, and used to generate electricity through conventional steam turbine or binary cycle power plant equipment. The technical concept of EGS is not new. Research programmes in the US, Europe, and Australia demonstrated the physics of EGS in the 1980s and 1990s. What has changed is the combination of oil and gas drilling technology, advanced seismic monitoring, and the engineering experience with hydraulic fracturing that the shale oil and gas industry has developed over the past two decades. The ability to drill deeper, faster, and with greater directional control, to monitor subsurface fracture development with precision, and to manage induced seismicity, has moved EGS from a research demonstration to a commercially developing technology whose first projects outside experimental settings are now in development.
Fervo Energy in the United States is the company most directly responsible for demonstrating that modern oil and gas drilling techniques applied to geothermal development can make EGS commercially viable in geological settings outside the conventional hydrothermal resource areas. Its Project Red demonstration in Nevada, drilling horizontal wells in hot granite using directional drilling technology from oil and gas, demonstrated continuous power output at commercially relevant efficiency levels that conventional geothermal development techniques could not have achieved in the same geological setting. Fervo has secured power purchase agreements with Google and Nevada utilities for its commercial project pipeline, providing the offtake certainty that geothermal project finance requires.
The Drilling Cost Problem and the Path to Resolution
The commercial constraint on geothermal energy development that technology cannot yet fully resolve is drilling cost. Geothermal wells must be drilled to depths of three to ten kilometres in rock conditions that are abrasive, high-temperature, and corrosive to conventional drill bits and equipment. The drilling cost per metre in geothermal conditions substantially exceeds drilling cost in the oil and gas formations that the equipment was designed for. For conventional geothermal wells whose power output per well is limited, this drilling cost creates a capital cost per megawatt that is difficult to compete with solar and wind in most markets. The technology investment directed at reducing geothermal drilling cost includes plasma pulse drilling systems whose energy-based rock fragmentation approach could dramatically reduce the drill bit wear that is the dominant drilling cost driver, and millimetre wave energy drilling systems whose technology is being developed by Quaise Energy with Department of Energy support.
Top 10 Companies in Geothermal Energy Globally
- Fervo Energy: Most commercially advanced EGS developer; its Project Red demonstration and subsequent commercial agreements with Google and Nevada utilities make it the reference case for modern geothermal development, and its horizontal well EGS approach is the technology template that the next generation of geothermal developers are following.
- Ormat Technologies: US-listed geothermal developer and power plant equipment manufacturer operating geothermal plants across the US, Kenya, Guatemala, and Honduras; its vertically integrated model combining plant development with equipment supply creates the economic advantage that pure-play developers cannot replicate.
- Calpine (The Geysers): Operates The Geysers, the world's largest geothermal power complex in Northern California; its decades of operational data and resource management experience at The Geysers represent the most extensive geothermal reservoir engineering knowledge base in private hands.
- Quaise Energy: MIT spin-out developing millimetre wave energy drilling technology that could vaporise rock at depths beyond conventional drill bit capability; its technology would enable access to the ubiquitous high-temperature rock at ten-kilometre depths that exists everywhere but that conventional drilling cannot access economically.
- Dandelion Energy: Residential and commercial ground source heat pump company providing geothermal heating and cooling to New England homes; its standardised drilling and installation process makes geothermal home heating accessible to the mass residential market that custom geothermal installation has always been too expensive to serve.
- Hot Rock Energy: Australian EGS developer targeting the Cooper Basin, one of the hottest sedimentary basins in the world; its proximity to the Australian gas network and its target market of industrial heat supply differentiates it from the electricity-focused EGS developers that dominate the US market.
- Reykjavik Geothermal: Icelandic geothermal developer applying Iceland's unparalleled geothermal engineering expertise to international project development; its Corbetti and Tulu Moye projects in Ethiopia represent the export of Icelandic geothermal expertise to East Africa's rift valley geothermal resource, one of the world's largest undeveloped conventional geothermal prospects.
- Eavor Technologies: Canadian company developing a closed-loop geothermal system that circulates working fluid through a sealed underground pipe network rather than through fractured rock; its technology eliminates the induced seismicity risk of EGS while providing geothermal heat access in geological settings unsuitable for both conventional and EGS development.
- Turboden (Baker Hughes): Organic Rankine cycle power plant manufacturer whose technology is used in binary cycle geothermal plants that generate electricity from lower-temperature geothermal resources; its ORC systems extend the commercially viable geothermal resource base below the temperatures at which conventional steam turbines can operate.
- SLB: Oilfield services company applying its drilling technology, well engineering, and subsurface characterisation expertise to geothermal development; its partnership with Nabors Industries on geothermal drilling automation and its investment in geothermal well design are the commercial bets that the largest oilfield services company is making on geothermal's technology transition from oil and gas drilling.