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Case Study

The Potential for Superhot Rock Energy in the United States

What if there were a ubiquitous, always-on renewable energy source with the potential to replace fossil fuel power generation and meet much of the world’s future energy needs? What if that energy source could provide firm power without variability issues? What if it had a low land footprint and was available around the world, reducing the need to import energy? 

This energy source is possible. It’s called superhot rock energy.

The power of superhot rock geothermal energy

Superhot rock energy is an emerging energy source that will harness massive stores of renewable energy by pumping water deep into hot underground rocks, where it naturally heats up and then returns to the surface as steam. That steam could be used to produce carbon-free electricity, clean hydrogen, and other high-energy-intensity products. 

Traditional geothermal systems in operation today only work in regions where hot water naturally exists near the earth’s surface. By contrast, superhot rock energy systems would reach deeper into the earth and wouldn’t require underground sources of water, making them viable across the globe. With appropriate investment to overcome technological hurdles, superhot rock energy could reach commercial scale. If this is achieved, superhot rock energy could provide clean firm power at scale without the import risk and land-use footprint of other energy sources. 

Superhot rock energy’s enormous potential in the United States

First-of-a-kind modeling from Clean Air Task Force and the University of Twente in the Netherlands estimated superhot rock energy potential around the world. This modeling represents preliminary estimates of superhot rock potential, rather than confirmed resources. Nevertheless, it suggests that the United States is well endowed with superhot rock resources, as illustrated in our global map.i

CATF’s model finds superhot rock energy potential across about 20% of the United States’s land area — amounting to more than 750 thousand square miles — at depths below approximately 8 miles (12.5 km). With a concerted focus on deep drilling research and technology innovation, the United States should be able to access significant amounts of superhot rock energy.

Just 1% of the United States’s superhot rock resource has the potential to provide 4.3 terawatts of energy capacity (see Figure 2), which could generate nearly 36,000 terawatt-hours (TWh) of electricity. Though these numbers are only preliminary, their scale is enormous. To provide perspective, New York City consumed 53 TWh of electricity in 2019, so the United States’s superhot rock energy resource capacity could theoretically satisfy the annual electricity demands of nearly 680 additional cities equivalent to New York City.

Energy demand in the United States

The United States’s energy demand is projected to rise over the coming decades due to a growing population, higher per-capita energy consumption, and the electrification of additional sectors of the economy. The country will also need to adopt more energy-intensive technologies to adapt to rising temperatures and extended droughts, while shifting its energy sector away from fossil fuels.

The United States’s superhot rock energy capacity potential is significantly more than the country’s total electricity demand for 2021. If fully deployed and utilized, the United States’s superhot rock resource potential would exceed the country’s 2021 electricity demand by over 30,000 terawatt-hours. This type of excess generation potential could be exported in the form of high-electricity consuming products or zero-carbon fuels.


Environmental and health benefits

The U.S.’s Nationally Determined Contribution (NDC) under the Paris Agreement aims to reduce emissions by over 3450 megatonnes of CO2eq annually by 2030, and the country has a separate goal of 100 percent carbon pollution-free electricity by 2035. Using just 1% of the United States’s superhot rock energy endowment to replace coal and gas for in electricity generation would eliminate over 1600 megatonnes of carbon emissions – equivalent to nearly half of the U.S.’s NDC goal. While it is improbable that superhot rock energy will reach commercial scale in time to support the U.S.’s 2030 clean energy goals, this finding illustrates its potential to enable the country’s low-carbon energy strategy over time. Superhot rock energy would also provide air quality and health benefits by reducing nitrogen oxides, sulfur dioxide, particulate matter, and other toxic pollutants associated with the combustion of fossil fuels. And excess superhot rock energy could help the U.S. produce zero-carbon fuels for decarbonizing industrial and transportation sectors.

Leveraging subsurface expertise

The United States is renowned for its subsurface expertise and infrastructure. The country’s oil and gas sector is well poised to develop superhot rock on both domestic and foreign soil. U.S. oil and gas companies maintain deep expertise in many of the technical areas needed to deploy superhot rock energy quickly and a fleet of international assets, such as drilling rigs and contractual partners, that could do so at a global scale. Many of the electricians, mechanics, geoscientists, and more currently working in the U.S.’s oil and gas sector could find similar employment in the superhot rock industry, enabling a zero-carbon employment pathway. Meanwhile, an intensive drilling and resource development program by well-funded consortia that include oil and gas industry players around the country could provide the knowledge and innovation needed to develop and rapidly commercialize superhot rock energy.

Enabling a reliable and efficient grid

Superhot rock energy is available around the clock, rain or shine. An electricity system without this type of firm power requires building excess generation and transmission capacity to ensure there is always enough to meet demand. For example, a recent study of California found that an energy system that includes clean firm power would require one-third the new transmission compared to one without these resources. Finally, the 24/7 production profile of superhot rock energy makes better use of existing grid infrastructure by operating reliably and consistently, reducing reliance on demand-side shifting and expensive backup generation.

Efficient land use

Superhot rock energy is expected to be an extremely energy-dense resource, so its land requirements will be exceptionally low. Producing 1 GW of superhot rock energy is estimated to require roughly 7 sq mi of land, compared to approximately 100 sq mi of land for natural gas, 110 sq mi for solar, 325 sq mi for offshore wind, and 8,700 sq mi for biomass.ii

What will this cost?

According to preliminary modeling, electricity produced from mature superhot rock energy resources could be competitive with conventional power sources priced potentially as low as $25-40 (USD) per MWh on a global average.v Initial costs will be higher for first-of-a-kind projects but are likely to progressively decline in the same way that unconventional shale gas, solar, and wind project costs have declined after commercialization.



With the right funding and policy support, superhot rock energy could develop to its full potential: creating abundant renewable energy around the world. 

To learn more about the policy and technology innovations required to fulfill superhot rock energy’s revolutionary potential, visit our website. See more findings from CATF’s heat mapping research here. For inquiries, contact [email protected]

Endnotes

i. Methodology forthcoming

ii. Land use estimates for superhot rock energy from LucidCatalyst and Hotrock Research Organization. (2023). A Preliminary Techno-Economic Model of Superhot Rock Energy. https://www.catf.us/resource/preliminary-techno-economic-model-superhot-rock-energy/. Land use estimates for all other energy sources from Lovering, Jessica, Swain, Marian, Blomqvist, Linus, & Hernandez, Rebecca R. (2022). “Land-use intensity of electricity production and tomorrow’s energy landscape.” PLoS ONE 17(7): e0270155. https://doi.org/10.1371/journal.pone.0270155

v. The cost scenarios were developed using CATF’s SHR technoeconomic model (Herter, 2023). It is important to understand that water risk or restriction has not been considered. Furthermore, the LCOE report assumes engineering innovations in deep drilling, reservoir creation, well construction and downhole tools needed to allow the commercial development of a superhot rock geothermal project. These cost estimates do not represent the likely costs for first-of-a-kind superhot rock plants. Rather, the report estimates costs for Nth-of-a-kind plants. Furthermore, the report is considering operation conductions and knowledge present in the United States. The numbers have not been adjusted for regional cost biases.

Future state of superhot rock:
Key steps to success

Private and public investment

Investment from both private and public sources is needed to help superhot rock energy reach its full potential. It will require resources of governments, geothermal industry, academic institutions, oil and gas industry, and technology companies.

Government investment

Early government investments can jumpstart the process of commercialization by providing drilling campaign incentives, funding early-stage R&D to “de-risk” superhot rock in the public and private sector, funding pilot projects, and enhancing cooperation among international projects.

Regulatory
regime

New policies are needed to ensure that superhot rock energy development is both safe and efficient. Institutional frameworks are also required to provide the resources needed for development and scalability at a global level.

Curious to learn more?

Take a deeper dive into superhot rock

Learn more about how the superhot rock process works and explore the potential benefits this source of energy has to offer.