Energy and water have always been closely linked – and geothermal is no exception. As Enhanced Geothermal Systems (EGS) continues to scale, one of the most common questions we receive at Fervo is: How much water does geothermal use? In this post, we take a closer look at the connection between geothermal energy and water.

Overview

• Water plays a pivotal role in geothermal drilling, site construction, and power plant operations.
• EGS technology has a comparably lower impact on water consumption and use than those of traditional hydrocarbon production or power generation facilities.
• Fervo’s projects do not require freshwater. Instead, we use degraded or brackish water – eliminating any potential competition with agriculture, communities, or ecosystems for vital water sources. One hundred percent of Fervo’s operations to date have been completed with degraded water.
• Although the arid regions of the western US where Fervo operates are often thought of as “water scarce,” US Geological Survey studies show that degraded and brackish water resources are actually abundant throughout the west. US Department of Energy estimates show that over 90% of future EGS growth can leverage degraded water, without impacting freshwater resources.

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Fervo’s Technology Use and Innovation

All power generation facilities require water, which can have varying degrees of impact on the surrounding water system. Even within the geothermal industry, water use varies by technology type.

Geothermal power plants generate electricity from hot subsurface brine, often reinjected underground after the power conversion process. Geothermal power conversion technologies can be divided into three distinct categories: dry steam, flash steam, and binary cycle (most often Organic Rankine Cycle), and each has different impacts on water use.

In a dry steam or flash steam power plant, geothermal steam is sent directly to power a turbine and then goes through an evaporative cooling process. Dry steam and flash plants can therefore have significant loss of reservoir fluid due to evaporation to the atmosphere.

By contrast, a binary plant utilizes dry cooling technology. In this system the brine remains a liquid and instead vaporizes a secondary working fluid, which then powers a turbine. The geothermal brine is then reinjected into the geothermal reservoir in a fully closed-loop process. All the fluid that is brought up from the reservoir is entirely reinjected into the formation where it came from.

Fervo’s future development pipeline will only use dry cooling technology – the most environmentally friendly combination for geothermal development. The remainder of this post will summarize Fervo’s approach.

Deployment: Water Sourcing and Use in Fervo’s Projects

Water Quality

None of Fervo’s operations requires freshwater. Instead, we prioritize degraded water sources, typically defined as water with a Total Dissolved Solids content of more than 1000 mg/l. Degraded water includes contaminated groundwater, treated municipal effluent, industrial process water or wastewater, irrigation return water, storm water runoff, brackish water, and other types of water impacted by human activity. To date, Fervo’s Project Red in Nevada and Project Cape in Utah have exclusively used degraded water in all field operations without competing for freshwater sources. Based on analysis from the Department of Energy in the 2019 GeoVision Study, over 90% of future EGS deployment could occur in areas that exclusively use non-freshwater.

The US Environmental Protection Agency sets a secondary standard of a maximum of 500 ppm TDS for freshwater drinking quality, whereas water with 3,000-5,000 ppm TDS is considered “poor” for agricultural use.

Water sourced for drilling, stimulation, and well testing at Project Red has a TDS content ranging from 3,000 to 4,000 ppm. Similarly, Project Cape has a TDS content of approximately 4,680 ppm, drawn from wells between 650 and 1,500 feet deep – consistent with findings from the Utah FORGE site, where groundwater TDS ranges from 4,000 to 6,000 mg/L. Future wells are currently designed to reach depths of ~2,500 feet to allow Fervo to make use of lower quality water and to mitigate any potential impacts with other users (mostly agricultural) that may be sourcing from shallower depths.

Fervo’s water use is also non-consumptive because water is reinjected into the geothermal formation after use and remains in the same hydrogeologic basin.

Water Availability

While the Western Desert is often considered a water-scarce region, it holds vast subsurface formations saturated with water, the quality of which generally decreases as depths increase. In many basins across Nevada, Utah, Idaho, Oregon, and New Mexico, thousands of feet of sedimentary formations exist before reaching the low-permeability basement rocks targeted for EGS projects, providing an opportunity for Fervo to utilize degraded water from these deeper saline formations without affecting high-quality freshwater sources.

Fervo’s approach to water sourcing has a minimal impact on fresh water sources and users and actively promotes and improves water sustainability and conservation. By utilizing degraded water from deep saline formations, Fervo helps alleviate pressure on scarce freshwater resources. This strategy ensures that high-quality water remains available for communities and ecosystems while enabling reliable, carbon-free energy production.

The next two sections go into detail on water use in the Development Phase and Operations Phase. During development, water is used for drilling, well stimulation, and power plant construction. During operations, water is used for power generation and project maintenance. It is important to remember throughout these sections that the water quantities described are non-freshwater sources and that many applications are non-consumptive.

Developing the Project

Drilling and stimulation are typically seen as water-intensive processes; however, the volumes required are minimal on a gallon per MWh basis. EGS employs well stimulation technology similar to that/those used for hydraulic fracturing in the oil and gas industry, to create permeability in reservoirs that would otherwise not be accessible or able to produce commercially viable quantities of geothermal brine. To date, Fervo’s stimulation operations have required approximately 300,000 barrels of degraded water per well. Based on Fervo’s recent well performance data¹, which demonstrates 8-10 MWnet per production well, and standard assumptions for power generation, the long-term water consumption rate is approximately 14 gallons of degraded water per MWh over a 30-year well life. This is a negligible amount of water use when compared to full life cycle water consumption of traditional power generation technologies such as coal, nuclear or natural gas which ranges from 238-845 gal/MWh². Even though the water used in well stimulation receives significant attention, because EGS-based power output is so productive per well, it has a negligible impact on water use in the power system.

Drilling an EGS well has even less of an impact on water consumption. Fervo’s wells are typically 12,000 to 15,000 feet deep and use approximately 8,000 barrels of water, primarily to maintain the drilling fluid system that plays an important role in cooling the tools used for drilling and transporting drill cuttings out of the well. Using the same calculations applicable to well stimulation, EGS drilling uses less than 1 gallon of water per MWh over a 30-year well life. Additionally, a large portion of this water is left in the subsurface, replenishing the formation, often more than the original use of the water right.

Construction activities to build the power plant use far less water than drilling or well stimulation and the overall contribution to water use in EGS is negligible on a per MWh basis.

Operations

In EGS operations, heat is brought to the surface by circulating geothermal brine through the reservoir through injection wells and production wells. The injected water circulates through fractures in the rock, absorbing heat before traveling through the production well to the surface, where it is used to generate electricity. As this fluid is injected into the injection well, some non-recaptured water naturally travels away from the primary flow path into the reservoir’s porous rock and remains in the groundwater column or reservoir instead of immediately returning to the surface through the production well. Despite deviating from the primary flow path, this “leak off” fluid results in a non-consumptive system, as it is not consumed or lost, but stays in groundwater column or reservoir for future use.

Previous studies have shown circulation recapture rates ranging from 80% to 99%, depending on reservoir design and geology³. Fervo reported an 80–90% recapture rate during an initial 37-day production test at the Project Red site⁴, while the Utah FORGE project observed an 86% recapture rate during a 30-day test, with rates continuing to improve⁵. Similarly, the Fenton Hill EGS project demonstrated a 93% recapture rate in a 1993 test⁶. Fervo’s and the Utah FORGE recapture rates can be expected to increase over time as the reservoir pressurizes and saturates due to continued water circulation and retention of leak-off fluid.

Additionally, those earlier tests were conducted using a doublet well system, an older well design that is less effective at recapturing fluid and the circulation recapture rates can be considered to reflect lower estimates. At scale, EGS development should yield higher recapture rates through Fervo’s proprietary and strategically-designed well patterns, utilizing repeated sequences of injectors and producers to minimize water loss.

During operations, Fervo anticipates cycling a non-consumptive volume of water of approximately 50–200 gallons per MWh, exclusively sourced from degraded water in deep saline formations. Long-term modeling, calibrated to early field data, predicts high circulation recapture rates, consistent with findings from Argonne National Laboratory.

Fervo is developing new technologies and advancing existing technologies that are over time expected to eliminate even this modest sourcing requirement. These innovations include drilling drainage wells to recapture water at the field boundaries and utilizing artificial lift solutions – such as downhole pumps – to reduce reservoir pressure near production wells, thereby strengthening the pressure sink and minimizing or eliminating water outflows and loss.

Looking Ahead: Opportunities for Future Innovation

Maximizing Water Resource Efficiency through Co-location

Co-locating EGS projects with data centers also offers significant benefits, particularly in water conservation and cooling efficiency. EGS enhances the capability of data centers to adopt dry cooling and zero-water cooling technologies, eliminating the need for water consumption in cooling operations. Additionally, the integration of advanced cooling technologies, such as absorption chillers that utilize low-grade geothermal heat, can further improve data center efficiency without substantial cost increases and provides a positive environmental impact. Moreover, because EGS relies on degraded water sources rather than fresh water, its development helps alleviate water scarcity, preserving high-quality and fresh water for other critical uses. This synergy between EGS and data centers offers a sustainable, resource-efficient solution to meet the growing energy and cooling demands of large-scale, AI-driven and AI-generating facilities.

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1. https://eartharxiv.org/repository/view/7665/ ↩︎
2. https://iopscience.iop.org/article/10.1088/1748-9326/6/3/034023/pdf ↩︎
3. https://www.osti.gov/biblio/1117360 ↩︎
4. https://eartharxiv.org/repository/view/5704/ ↩︎
5. https://gdr.openei.org/submissions/1683  ↩︎
6. Brown et al. (2012). Mining the Earth’s Heat: Hot Dry Rock Geothermal Energy. Springer.  ↩︎