Case Study
The Potential for Superhot Rock Energy in Africa
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.
Figure 1: Animation of a superhot rock energy system
Superhot rock energy’s enormous potential in Africa
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 Africa is well endowed with superhot rock resources, as illustrated in our global map.i
CATF’s model finds superhot rock energy potential across about 18% of Africa’s land area — amounting to more than 5.3 million square kilometers — at depths below 12.5 km. With a concerted focus on deep drilling research and technology innovation, Africa should be able to access superhot rock nearly anywhere.
Just 1% of Africa’s superhot rock resource has the potential to provide 12.4 terawatts of energy capacity, which could generate over 100,000 terawatt-hours (TWh) of electricity. Though these numbers are only preliminary, their scale is enormous. To provide perspective, global electric capacity in 2021 was 8.5 terawatts, so just 1% of Africa’s superhot rock energy resource represents a 1.5x increase over the entire world’s current electric capacity. The country of Ethiopia consumed 15.5 TWh in 2022, so Africa’s superhot rock energy resource capacity could theoretically satisfy the annual electricity demands of about 6,500 additional countries equivalent to Ethiopia.
Energy access and development
Africa’s energy demand is projected to rise over the coming decades due to a growing population, economic development, and higher per-capita energy consumption. African countries will also need to adopt more energy-intensive technologies to adapt to rising temperatures and extended droughts, while shifting their energy sectors away from fossil fuels.
The immense capacity of superhot rock energy could also play a crucial role in fostering sustainable development across Africa. Superhot rock energy projects can increase the overall capacity of the electrical grid, providing more reliable and consistent power to homes, businesses, and industries. Improved access to electricity is crucial for economic development.
The development of superhot rock energy projects also requires a workforce, creating job opportunities in various fields such as engineering, geology, and maintenance, which can reduce unemployment and poverty rates across Africa. Finally, the development of superhot rock energy projects may attract foreign investment and expertise. Collaborating with international partners can bring in funding, technology, and knowledge, fostering a supportive environment for sustainable development.
If fully deployed and utilized, Africa’s superhot rock resource potential could help meet the region’s growing energy demand, reduce energy poverty, and spur economic growth.
Figure 2: The total capacity potential of superhot rock energy if fully developed across countries with available heat in Africa
Environmental and health benefits
The combined Nationally Determined Contributions (NDCs) under the Paris Agreement for all African countries that have significant superhot rock energy resourcesii aim to reduce emissions by about 850 megatonnes of CO2eq annually by 2030. Additionally, some countries in the region have adopted zero-carbon or climate neutrality goals.iii Africa’s superhot rock energy endowment could replace fossil-based energy sources and their associated carbon emissions. While it is improbable that superhot rock energy will reach commercial scale in time to support 2030 climate goals, it does have the potential to enable low-carbon energy development 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 Africa produce zero-carbon fuels for decarbonizing industrial and transportation sectors.
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 12 km2 of land, compared to approximately 160 km2 of land for natural gas, 180 km2 for solar, 520 km2 for offshore wind, and 14,000 km2 for biomass.iv
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.
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.
Figure 3: Illustrative graph shows how electricity produced from superhot rock is expected to be competitive for Nth-of-a-kind plants (NOAK) based on estimated levelized cost of electricity after full 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. Angola, Cameroon, Chad, Djibouti, Eritrea, Ethiopia, Kenya, Niger, Nigeria, Somalia, South Sudan, Sudan, Mozambique, Rwanda, and Tanzania
iii. Ethiopia and Nigeria
iv. 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.