The USGS conducted assessments of domestic geothermal resources in 1970, 1971, 1975, 1979, and 2008, according to the CRS, which adds that the Energy Act of 2020 directed the USGS to update its 2008 assessment and consider potential resources using other geothermal technologies. Furthermore, the report cites the Department of Energy’s Office of Geothermal which supports innovations in technology to reduce the risks and costs of geothermal energy development.

Among the technologies that foster access to geothermal resources is drilling, specifically drilling on public land, which is governed by the Bureau of Land Management (BLM), and which also regulates water and geothermal drilling reserve pits. For such drilling to commerce, a permit is needed with the process requiring operators to submit a “geothermal drilling permit” (GDP) along with an operations plan detailing well pad design, water sources, and environmental protection procedures before construction, BLM says.

Furthermore, a BLM “Geothermal Guidance” document directs and monitors the operation of drilling reserve pits—also known as “sumps”—with the document designed to protect groundwater, surface resources, and wildlife. The areas covered by the guidance document include exploratory operations; drilling, completion and spacing of geothermal wells; plugging and abandonment of wells; general environmental protection requirements; plans of operation, permits, reports, records, and forms; pipelines and surface production facilities; and production and royalty measurement, equipment, and testing procedures.

The BLM says reserve pit design, the need for environmental compliance measures, and reclamation approaches vary depending on site-specific conditions. Of those, the impact on groundwater and wildlife are the most common environmental considerations, with some cases—such as adherence to regulations, or groundwater or soil conditions—necessitating the use of a synthetic liner.

Protecting Water Supplies, Pit Liners and Wildlife

Water supplies such as rivers, creeks, springs, lakes, ponds, and wells for use in drilling a proposed well are required to be identified on a map or plat, or may be described in writing, BLM says. Furthermore, an operator must indicate if there are plans to drill a water supply well on the leased land and, if so, the operator must describe the location, construction details, and expected production requirements in drilling a proposed well, with a description of how water will be transported and procedures for well abandonment. Operators must also identify access routes, and transportation method for all water anticipated for use in drilling a proposed well, with any newly constructed or reconstructed access roads crossing federal or tribal lands.

However, the chemical composition of most geothermal drilling fluids and muds, completion fluids, and produced fluids that are discharged to reserve pits does not warrant pit liners, says BLM. Pit liners are required only when specific groundwater, soil conditions, or local regulations make them necessary; most standard geothermal drilling muds and fluids do not automatically mandate liners based on chemical composition alone, according to BLM.

Directly related to operators’ accessing water supplies “are concerns for wildlife” including the “potential for hazardous fluids, high water temperatures, and entrapment,” which can all impact wildlife, says BLM. Methods listed by BLM to reduce, or avoid, impacting wildlife include fencing, netting, and escape ramps with the need for each method dependent on localized site and environmental conditions.

Project Timelines

BLM monitors and tracks projects to ensure that project timelines are being met (to help operators stay on track, the BLM offers timeframe templates for GDP processing), the BLM directs each serving deputy state director (DSD) for minerals management and the division of minerals management to review all information required for permitting of NOIs and GDPs utilizing the “geothermal resources automated support system” database.

In cases where the processing time frames are not met, the first action will be for the BLM’s state geothermal program lead (SGPL) to follow up with staff from the appropriate field office (FO) to determine if the delay is reasonable. In cases where the SGPL determines that any delays are not reasonable, they will be referred to the DSD minerals management who is to consult with the FO management.

Those are basic requirements to drill for geothermal resources, as well as to reclaim reserve pits following geothermal drilling operations, according to BLM, with reserve pits often remaining in place to accommodate multiple phases of drilling and well testing, with those drilling pits eventually backfilled and decommissioned.

Want More Geothermal Insights?
Explore the inaugural Ground2Grid Thermal Energy Summit, launching in 2027, and connect with the ideas shaping the future of geothermal energy. Learn more.