The U.S. Department of Energy’s (DOE) Geothermal Technologies Office (GTO) collaborates on and develops several publications each year to inform and educate about advances in geothermal technology. Explore below for important analyses, planning documents, technical reports, and more, and check out the Office of Scientific and Technical Information for even more Office of Energy Efficiency and Renewable Energy publications on geothermal technologies and energy.


This analysis from Oak Ridge National Laboratory and the National Renewable Energy Laboratory (NREL) assesses the potential impacts of national-scale mass deployment of geothermal heat pumps (GHPs). The study concludes that, coupled with building envelope improvements, retrofitting around 70% of U.S. buildings with GHPs could reduce electricity demand by as much as 13% by 2050 versus decarbonizing without GHPs. This reduction in demand would avoid as much as 24,500 miles of new grid transmission lines by 2050—enough to cross the continental United States eight times.

This analysis from Lawrence Berkeley National Laboratory quantifies and characterizes the lithium resource in California’s Salton Sea region, including current and future amounts of lithium that may be recovered in geothermal brines, preliminary estimates of the effects of extraction on lithium concentrations, and potential environmental impacts of expanding lithium extraction operations in the Salton Sea Known Geothermal Resource Area (KGRA). The analysis concludes that total lithium resources in the region could produce more than 3,400 kilotons of lithium, enough to support over 375 million batteries for electric vehicles—more than the total number of vehicles currently on U.S. roads.  

Other Geothermal Publications of Interest

GTO contributes to many reports and other publications beyond those that it funds directly. Explore some of those resources:

WGA's Heat Beneath Our Feet Initiative Report

IEA Geothermal's Annual Reports

View the fact sheet highlighting the key findings from the GTO-funded analysis, "Characterizing the Geothermal Lithium Resource at the Salton Sea."

In 2019, GTO with support from NREL released the GeoVision analysis and the associated Non-Technical Barriers Task Force report, the latter of which identified states in the eastern and southern United States that did not then have geothermal regulations for power production or direct-use applications. The intent of this document is to provide information that states might find valuable when developing geothermal regulations that would be inclusive of all geothermal power and heating technologies (e.g., conventional and nonconventional power production and direct-use applications) with applicability in all states. As part of this project, the NREL project team reviewed and catalogued existing state and Federal geothermal regulations, compiled best practices from geothermal and other extractive industries, and established a Geothermal Regulatory Stakeholder Working Group to advise and review the geothermal regulatory synthesis.

Fact Sheet Cover for What is Geothermal Energy?

Wondering what geothermal energy is all about? Get fast facts about this renewable, reliable, and clean energy source that’s right under your feet, including a peek at its role in the natural world, home heating and cooling, and power production.


Data sheet cover for What are Geothermal Heat Pumps?

Geothermal heat pumps (GHPs) are clean, efficient systems for heating and cooling that can be installed in all 50 states. Learn how GHPs work, what types of GHP systems are available for use in homes and other buildings in the United States, and seven reasons why GHPs might be a perfect solution for your heating and cooling needs. 


In 2022, DOE's NREL brought together federal and state regulators, geothermal industry representatives, environmental non-governmental organizations, and Indian Tribes for multiple GTO-supported meetings/forums to discuss challenges and opportunities related to geothermal regulatory approvals and permitting. This report synthesizes the views expressed during those discussions.

Report cover for Enhanced Geothermal Shot Analysis for the Geothermal Technologies Office developed by NREL.

This analysis, prepared by NREL, quantifies the potential of enhanced geothermal systems as a widespread renewable energy option in the United States. It finds that the Enhanced Geothermal Shot™ goal of significantly expanding enhanced geothermal systems deployment by cutting costs 90% to $45 per megawatt-hour by 2035 is ambitious but achievable with technology advances.


Salton Sea Geothermal Development: Nontechnical Barriers to Entry—Analysis and Perspectives (2022)

This report analyzes the viability of and provides recommendations for streamlining geothermal development at the Salton Sea in Imperial County, California. Primary findings are that certain nontechnical barriers such as permitting costs play only a minor role in determining the viability of geothermal development in this location. Other barriers such as permitting timelines, government/agency coordination, and the potential colocation of lithium extraction with a geothermal plant may result in much larger impacts on project viability.

Non-Technical Barriers to Geothermal Development in California and Nevada (2022)

This report presents the study results on non-technical barriers that may influence geothermal project development in California and Nevada, including 1) an analysis of federal, state, and local geothermal regulatory and permitting processes and considerations; 2) case studies analyzing attributes at specific project locations; 3) an analysis of cost and timeline implications for geothermal project development; and 4) a qualitative analysis conducted through a series of semi-structured interviews with regulatory agencies and geothermal project developers in California and Nevada.

Economic Impact of Permitting Timelines on Geothermal Power in California, Nevada, and Utah (2022)

This study demonstrates how geothermal permitting timelines can vary from six months to several years, depending on the presence or absence of biological resources, cultural resources, and sensitive environmental issues at the project site. It also analyzes how the potential impacts of these permit barriers can range from investors abandoning geothermal development to making the product (i.e., electricity) more expensive and uncompetitive.

Graphic of a mountain scene in the distance, with a road leading to the mountains, and the words "MYPP: Multi Year Program Plan."

The GTO Fiscal Year 2022–2026 Multi-Year Program Plan (MYPP) outlines GTO’s vision and mission, presenting a high-level technology structure for key areas of GTO research to support the growth and long-term contribution of geothermal energy to the U.S. electricity grid and American homes and buildings.

2022 Peer Review Report (2022)

GTO regularly conducts peer reviews to obtain robust, documented feedback for program planning, during which qualified independent experts assess the progress and contributions of projects in GTO’s portfolio and provide high-level, strategic feedback. The findings help GTO identify strategies that will enhance existing efforts and shape future work for GTO-funded projects. Read all GTO peer review reports on the Geothermal Technologies Office Peer Review page.

The Influence of Geothermal Patents Funded by the U.S. Department of Energy's Geothermal Energy Technologies Office and Other DOE Offices (2021)

This report describes the results of an analysis tracing the technological influence of geothermal energy research funded by GTO and its precursor programs, as well as geothermal energy research funded by other offices in DOE.

NREL 2021 U.S. Geothermal Power Production and District Heating Market Report cover showing geothermal drilling site.

This NREL and Geothermal Rising report provides policymakers, regulators, developers, researchers, engineers, financiers, and other stakeholders with information and data reflecting the 2019 geothermal power production and district heating markets, technologies, and trends in the United States. The report also evaluates the impact of state and federal policy, presents current research on geothermal development, and describes future opportunities for the U.S. geothermal market and industry.

GeoVision (2019)

Harnessing the Heat Beneath Our Feet report cover

To evaluate the potential for geothermal energy to contribute to America’s energy future, GTO initiated the GeoVision analysis—a detailed research effort to explore opportunities for increased geothermal deployment and the pathways necessary to overcome technical and non-technical barriers to such deployment. The GeoVision analysis evaluated opportunities for successful geothermal deployment based on three key objectives, and used rigorous quantitative models to assess geothermal deployment potential under scenarios that considered a range of technologies, market conditions, and barriers.

Frontier Observatory for Research in Geothermal Energy: A Roadmap (2019)

The Frontier Observatory for Research in Geothermal Energy (FORGE) Roadmap provides technical research recommendations to the Geothermal Technologies Office, FORGE’s Science and Technology Analysis Team, and the broader research community for FORGE’s operation as an enhanced geothermal systems (EGS) research site. It describes discrete actions that could be carried out at FORGE to overcome key technical challenges necessary for EGS to be reliable and reproducible, addressed in three sections: critical research areas, enabling research and development, and implementation principles. 

FORGE Technical Reports

The Frontier Observatory for Research in Geothermal Energy (FORGE) initiative is currently in phase three and has developed a number of technical reports including informational flyers and the FORGE roadmap. The roadmap activities discuss how to build a future large-scale enhanced geothermal system beyond the FORGE site.

Map of the Geothermal Resources of the United States

The Lawrence Livermore National Laboratory's (LLNL) Tom Edmunds and Pedro Sotorrio created this GTO-commissioned study to explore economic incentives that would motivate geothermal plant operators to consider a more flexible geothermal energy supply. The report showcases innovative research that contributes to the geothermal industry’s understanding of future energy markets and demonstrates the benefits of geothermal within the broader context of renewable energy sources.

Report cover of Geothermal Power and Interconnection: The Economics of Getting to Market

This report provides a baseline description of the transmission issues affecting geothermal technologies, intended for geothermal experts in either the private or public sector who are less familiar with how the electricity system operates beyond the geothermal plant. The report provides a comprehensive overview of the grid—how it is planned, used, and paid for—and then overlays onto this "big picture" three types of geothermal technologies: conventional hydrothermal systems, emerging technologies such as enhanced engineered geothermal systems and geopressured geothermal, and geothermal coproduction with existing oil and gas wells.

Geothermal History Reports (2010)

Report cover of A History of Geothermal Energy Research and Development in the United States-Exploration, Volume 1

GTO’s series of four history reports on Geothermal Energy Research and Development in the United States highlight the history and significant accomplishments of major research programs and projects in geothermal energy exploration, drilling, reservoir engineering and energy conversion in the United States from 1976-2006.

Download A History of Geothermal Energy Research and Development in the United States, 1976-2006:

Volume 1: Exploration
Volume 2: Drilling
Volume 3: Reservoir Engineering
Volume 4: Energy Conversion