AltaRock has always been focused on developing technologies to help scale geothermal resources everywhere. We started in 2007 focused on moderate EGS targets of 200-250 °C at Newberry. While successful in developing EGS methods, technologies and tools, by 2014 it became clear that moderate-temperature EGS could not compete on price with solar, wind, or natural gas. EGS with greater energy density, by tapping into higher temperature rock, would make it price competitive the US. AltaRock has determined that SuperHot Rock (SHR) resources, which exploit supercritical water in the reservoir, could produce 5x -10x energy of a typical geothermal well, and allow geothermal energy to reach utility scale globally.

Slowing climate change requires creating widespread multi-terawatt scale carbon-free energy sources by 2050. With adequate investment in needed technologies, AltaRock believes that SHR geothermal can meet that challenge—provide very low cost, low carbon energy everywhere, without the need for large-scale transmission and storage. AltaRock plans to demonstrate the first SuperHot Rock resource at its Newberry, Oregon site by 2025, followed closely by the first SHR power plant and large-scale commercial power development.


SuperHot Rock are reservoirs where water is in a supercritical state. Supercritical water is >375°C (707°F) and has a pressure greater than 220 atm (22 MPa), which is 220 times the pressure of our atmosphere. The reason we want supercritical water in the reservoir is that is has characteristics which make it an ideal heat mining fluid. Supercritical water is more dense than steam, ~300kg/m3, has a high specific enthalpy, >2,000 KJ/kg, and has 1/10th the viscosity of liquid water. Compared to a traditional geothermal reservoir, a SHR reservoir will need half the heat transfer area to produce >2.5x the energy.
AltaRock has coined the term SuperHot Rock (SHR) as opposed to supercritical geothermal primarily to distinguish between natural hydrothermal geothermal system that produce supercritical resources, such as those being produced in Iceland and New Zealand. SHR is an engineered reservoir specifically designed at conditions to produce a supercritical fluid at depth.

Economic analysis conducted by AltaRock and reservoir modeling conducted by Baker Hughes have found that SuperHot Rock resources can achieve a competitive Levelized Cost of Electricity (LCOE) of <$0.05/kWh. In comparison, a conventional Engineered Geothermal System (EGS) target of 200-230 °C resource will ─ with the same net power output ─ produce power at an LCOE >$0.10/kWh. Conventional geothermal in the US, primarily low enthalpy resources utilizing binary turbines, produce power at $0.065-$0.075/kWh

The significant cost difference between SHR and conventional systems results from a greater energy density, 5-10x energy per well. In addition to being cheaper, SHR is environmentally friendlier, with 1/10th the water requirements and surface area footprint compared to conventional EGS or conventional geothermal. Only in places where steam can be directly produced from the ground, such as Iceland, can typical geothermal resources produce power <$0.05kWh, and these resources are exceedingly rare.

Many of the technologies needed to develop SHR resources exist today, but key technology challenges must be overcome. For context, 27 wells have reached SHR conditions already, some on purpose and some by accident, which shows that we can reach SHR conditions with current technology. But it is expensive, and innovation is needed to drive costs down. Additionally, coal and nuclear already create electricity with supercritical water or high pressure and temperature steam, technology that can be optimized for SHR resources to get comparable conversion efficiencies.
SHR development is challenged by well completion and reservoir stimulation. New tools to compete robust wells at SHR conditions are being developed around the world, and in some cases they are already seeing limited use in places like the Salton Sea. Further investment to develop and scale up these tools will solve the engineering challenges. Reservoir characterization and creation is even more challenging because empirical data on the behavior of crystalline rock at SHR conditions is very limited. Significant effort is required to develop the downhole instrumentation and stimulation tools for SHR reservoir creation. This is where AltaRock is putting most of its current development effort, and significant progress has already been made. AltaRock will be ready to develop the first SHR system soon, on the order of 3-5 years.

The key to creating a robust alternative to fossil fuels is developing a dispatchable power source, with zero emissions, at an affordable price. Dispatchable power means it is predictable, where the consumer knows when the power will be produced or can call on the power to be produced when needed. This contrasts with solar or wind, which, while affordable, are intermittent. They both need firming and massive infrastructure for utility scale development. When comparing the cost of intermittent solar or wind to geothermal (or any baseload resource) one must also include the costs of the storage and infrastructure needed to make these resources available 24/7, an issue too often ignored in power plant and system economics.
Non-hydrocarbon baseload power sources (e.g., nuclear fission and hydropower) all have limitations and challenges. On par, SHR geothermal can out compete all of these options on cost, environmental footprint, and infrastructure required. There is no waste, no fuel, and the primary energy source is unlimited. Fusion would come the closest to SHR in term of benefits, but SHR has far less engineering challenges, and SHR can be developed and scaled to meet the current global energy challenges with a fraction of the investment that has gone into fusion.

Yes, but primarily overseas. Academic and government/private partnerships have invested in SHR research in the EU, Japan, China, and New Zealand. Some of our favorite drilling projects are the Iceland Deep Drilling Project and the DESCRAMBLE project in Larderello, Italy (home of the world’s first geothermal power plant). GNS Science in New Zealand is doing some incredible research on natural supercritical systems. The Japan Beyond Brittle Project (JBBP) is another amazing source of information on rock mechanics at SHR conditions, and they have published multiple papers outlining their findings. In the US, technology development at supercritical conditions is occurring at Pacific Northwest National Laboratory, Ozark Integrated Circuits, and Quaise Energy, all of whom AltaRock has partnered with. AltaRock funding helped get Quaise Energy started, and they are developing a directed energy drilling technology which can vaporize rock to enable very deep geothermal wells for a reasonable cost. This technology is critical to scaling SHR globally.

AltaRock is developing the necessary tools and methods to create reservoirs in SuperHot Rock. We are also pursuing partnerships with drilling companies, power plant engineering and manufacturing firms, and other specialists. We plan to deploy our proprietary technologies at Newberry Volcano, Oregon, and develop the world’s first SHR power plant. From there, we will begin the journey of deploying our technology around the world. There is still a lot of development work to be done, but research is already under way and announcement and white papers are pending. We plan on publishing the results of our research, if it is not proprietary, for the public to review and engage with. We are excited to start sharing our ideas with the rest of the geothermal community and work on some of these challenges together.