Title 42The Public Health and WelfareRelease 119-73

§17191 Definitions

Title 42 › Chapter CHAPTER 152— - ENERGY INDEPENDENCE AND SECURITY › Subchapter SUBCHAPTER V— - ACCELERATED RESEARCH AND DEVELOPMENT › Part Part B— - Geothermal Energy › § 17191

Last updated Apr 6, 2026|Official source

Summary

Gives short, plain meanings for key words used in these rules. Engineered: made to reach heat below ground, using methods (including stimulation or other techniques) to fix problems like poor rock connectivity, too little fluid, or low heat that needs deeper drilling or other heat sources. Eligible entity: a college, a national lab, a federal or state research agency, a nonprofit research group, a private company, or a group made of two or more of these. Enhanced geothermal systems: geothermal reservoirs that are created or improved by engineering rather than being purely natural. Geofluid: any fluid used to carry heat up from underground for use or power, but not oil or natural gas. Geopressured resources: hot deposits in sedimentary rock that are under high pressure and contain gas or methane. Geothermal: heat stored in the Earth’s crust that can be used directly or to make electricity. Hydrothermal: natural underground pockets of hot water or steam. Systems approach: solving or designing by focusing on the whole system’s performance, not just one part.

Full Legal Text

Title 42, §17191

The Public Health and Welfare — Source: USLM XML via OLRC

For purposes of this part:
(1)When referring to enhanced geothermal systems, the term “engineered” means designed to access subsurface heat, including stimulation and nonstimulation technologies to address one or more of the following issues:
(A)Lack of effective permeability, porosity or open fracture connectivity within the heat reservoir.
(B)Insufficient contained geofluid in the heat reservoir.
(C)A low average geothermal gradient which necessitates deeper drilling, or the use of alternative heat sources or heat generation processes.
(2)The term “eligible entity” means any of the following entities:
(A)An institution of higher education.
(B)A National laboratory.
(C)A Federal research agency.
(D)A State research agency.
(E)A nonprofit research organization.
(F)An industrial entity.
(G)A consortium of 2 or more entities described in subparagraphs (A) through (F).
(3)The term “enhanced geothermal systems” means geothermal reservoir systems that are engineered, as opposed to occurring naturally.
(4)The term “geofluid” means any fluid used to extract thermal energy from the Earth which is transported to the surface for direct use or electric power generation, except that such term shall not include oil or natural gas.
(5)The term “geopressured resources” mean geothermal deposits found in sedimentary rocks under higher than normal pressure and saturated with gas or methane.
(6)The term “geothermal” refers to heat energy stored in the Earth’s crust that can be accessed for direct use or electric power generation.
(7)The term “hydrothermal” refers to naturally occurring subsurface reservoirs of hot water or steam.
(8)The term “systems approach” means an approach to solving problems or designing systems that attempts to optimize the performance of the overall system, rather than a particular component of the system.

Legislative History

Notes & Related Subsidiaries

Editorial Notes

Amendments

2020—Par. (1). Pub. L. 116–260, § 3002(a), amended par. (1) generally. Prior to amendment, par. (1) defined the term “engineered”. Pars. (2) to (8). Pub. L. 116–260, § 3002(a)(2), (3), added par. (2) and redesignated former pars. (2) to (7) as (3) to (8), respectively.

Statutory Notes and Related Subsidiaries

Effective Date

Section effective on the date that is 1 day after Dec. 19, 2007, see section 1601 of Pub. L. 110–140, set out as a note under section 1824 of Title 2, The Congress.

Short Title

This part known as the “Advanced Geothermal Energy Research and Development Act of 2007”, see

Short Title

note set out under section 17001 of this title.

Reference

Citations & Metadata

Citation

42 U.S.C. § 17191

Title 42The Public Health and Welfare

Last Updated

Apr 6, 2026

Release point: 119-73