Posted on June 7, 2023 by Landon Stevens
Earlier this year, Houston-based geothermal energy developer Fervo announced an important new project to use its next-generation geothermal systems to power a direct air capture (DAC) facility. The announcement marks another milestone in the path towards a decarbonized economy and the expanded use of both geothermal and DAC technologies.
Geothermal + DAC = CO2 Reduction
The Need for Direct Air Capture of CO2
Deploying DAC technologies offer an exciting opportunity to add another tool to the toolbox for lowering global carbon dioxide (CO2) emissions by removing CO2 from the atmosphere.
Most decarbonization efforts focus on two areas. The first is keeping CO2 from going up into the atmosphere by generating electricity from technologies that don’t emit CO2 at all — think nuclear or renewables like hydropower and geothermal. The second effort is to use technology to capture the CO2 that would have been emitted from power plants and put it back underground – often referred to as carbon capture and storage (CCS).
The problem, unfortunately, is that there is already a heck of a lot of extra CO2 up in the atmosphere. DAC technologies offer a third option for decarbonizing by removing this CO2 from the air around us. If you have not heard of DAC, think of it as a massive vacuum cleaner that literally sucks carbon dioxide molecules out of the open air.
With recent Congressional action to pass bills with clean energy incentives, DAC technology is poised to see major growth moving forward. Last year, the U.S. Department of Energy (DOE) granted a series of awards to universities, utilities, and private businesses to study a variety of potential implementation models for DAC technologies ranging from use on nuclear and geothermal power plants to retrofitting steel and fertilizer plant operations.
Additionally, the Bipartisan Infrastructure Law (BIL), called for $3.5 billion in DOE funding to be used to establish four regional DAC hubs to, “demonstrate processing, transport, secure geologic storage, and/or conversion of CO2 captured from the atmosphere with DAC technology and accelerate commercialization of those technologies.” Project selections are expected later this summer and will provide another set of R&D opportunities for this technology.
Finally, under the tax package passed last year, the 45Q tax credit for CCS technologies included a special rule for DAC projects to expand tax incentives with the hope of enabling the industry to scale and export innovations on a global scale.
Geothermal energy is heat that radiates from the core of the Earth to the subsurface, produced by the decay of radioactive materials and residual heat from the planet’s formation. Geysers, hot springs, volcanoes, and fumaroles are all locations where geothermal energy reaches all the way to the Earth’s surface. It is easier to access geothermal resources in these locations, but geothermal resources are actually available anywhere if one drills deep enough. Geothermal energy, like wind and solar energy, is an inexhaustible natural resource.
Enhanced or engineered geothermal systems (EGS) create opportunities to use hot, dry rock by enhancing the permeability of a specific geology or by adding water. EGS developers drill wells and inject water at high pressures to crack rock. After permeability has been improved to increase fluid circulation, hot water can be drawn to the surface through a production well and used for electricity generation.
U.S. Potential for Enhanced Geothermal Systems
Dots Indicate Existing Hydrothermal Sites
Shaded Regions Are Potentially Suitable for EGS
Similar to recent policies adopted to support DAC, Congress has taken steps to support the geothermal industry in an effort to spur growth and innovation and to expand the map in facilitating its use in projects outside just the Western U.S. In addition to support in the tax package, the BIL set aside funding for the DOE to fund EGS demonstration projects. In February of this year, the DOE’s Geothermal Technology Office announced they would fund up to seven EGS projects with applications due this summer.
As of late 2022, there were 18 DAC plants in operation around the globe. Most of these are still smaller demonstration projects, but newly planned facilities like Occidental Petroleum’s in West Texas will be much larger, with the potential to remove up to 1 megaton (MT) of CO2 annually. To meet its net-zero goals, the U.S. could require 60 MT of CO2 removal each year by 2030, which would necessitate the buildout of an additional 60 plants similar in size to Occidental’s. Of note, Occidental has said that they could build up to 70 DAC projects globally by 2035 under current market conditions.
To result in a net carbon removal, DAC plants need electricity supplied by a 24/7 zero-emissions power source. Many DAC technologies also require access to a constant heat source, like that resulting from a geothermal plant, meaning EGS fits the bill perfectly.
Add to that the fact that the captured CO2 will need to be stored somewhere, usually in large underground geologic formations, and geothermal plant developers are uniquely qualified to pair with DAC plants. Companies like Fervo use next-generation technologies to survey the earth for their operations, and this same technology can be leveraged to help identify high-quality CO2 storage locations for DAC operations.
Today, the combo of geothermal and DAC is being used in Iceland, where Climeworks’ Orca plant has been removing CO2 from the atmosphere since 2021. Its system of fans, filters, and heaters are all powered by geothermal energy, and plans are underway to expand across the globe everywhere from Scotland to Texas.
As the U.S. market continues to take shape, recognizing the complementary nature of these technologies and their massive potential is producing a true ‘win-win’ for decarbonization. Not only will innovations in geothermal power allow for reliable, affordable, firm electricity generation, but when paired with energy intensive DAC projects, the impact will not just be ‘carbon neutral’ but could, in fact, be ‘carbon negative,’ offsetting past historical emissions.
This latest announcement is illustrative of the types of technological innovations that will be needed for the U.S. and the world to effectively decarbonize the economy in the future. Addressing climate change will necessitate an ‘all of the above’ approach to not only limit future emissions from reaching the atmosphere by expanding the use of technologies like hydropower, nuclear, geothermal, and renewables, but will also require cleaning up the current atmosphere. Continuing to prioritize support for innovative technologies like EGS and DAC and pairing these industries is not only promising for reducing emissions, but could also usher in a whole new innovative industry segment with global potential.