Background:
Geothermal energy is a renewable and diverse solution for the United States—providing reliable and flexible electricity generation and delivering unique technology solutions to America’s heating and cooling demands. Geothermal resources can be found nationwide, are “always on,” and represent vast domestic energy potential; however, only a fraction of this potential has been realized due to technical and non-technical barriers that constrain industry growth. In fact, the U.S. Department of Energy’s (DOE’s) Geothermal Technologies Office’s (GTO) recent GeoVision report concludes that with technology improvements, especially in areas relevant to enhanced geothermal systems (EGS), geothermal power generation could increase 26-fold from today, representing 60 gigawatts-electric (GWe) by 2050[1].
Enhanced Geothermal Systems (EGS) are engineered geothermal reservoirs, created where there is hot rock (175-300+°C), but little to no natural permeability and/or fluid saturation. During EGS development, subsurface permeability is enhanced via safe, well-engineered stimulation processes that re-open pre-existing fractures, create new ones, or a combination of both. These open conduits increase permeability and allow fluid to circulate throughout the rock. This fluid transports heat to the surface where electricity can be generated with current power generation technologies.
In addition to geothermal wells that have been targeted for EGS development, the hydrocarbon[2] industry also has an opportunity to contribute to the development of geothermal resources nationwide through the use of wells for power or heat production. The adaptation of hydrocarbon reservoirs, which are traditionally located in sedimentary basins, to geothermal production and utilization would expand the sector’s geographic reach outside of the Western U.S. where natural geothermal systems reside. Many hydrocarbon fields enounter temperatures high enough for geothermal energy and heat production. This unused heat, combined with the wealth of data, knowledge, workforce, and infrastructure in place in support of these fields underscores the benefits of exploring their geothermal potential. While a comprehensive nationwide resource assessment that evaluates the potential of existing hydrocarbon wells for geothermal development does not yet exist, a number of studies have looked at geographic subsets of the sedimentary basins of the U.S., where most hydrocarbon exploration and development occurs. Blackwell et al. (2006) provided a conservative estimate of 100,000 EJ of thermal energy in basins nationwide deeper than 4km[3]. A more detailed study on a subset of 15 U.S. basins by Porro et al. (2012) reported 135,000 EJ including only basins in the western United States (not including the Gulf Coast region)[4]. Finally, a study by Zafer & Cutright (2014) estimate the thermal energy resource base for the state of Texas alone to be 166,000 EJ[5].
Purpose:
Through periodic funding opportunity announcements (FOAs), GTO partners with industry, academia, national laboratories, industry experts, etc. to increase the use of domestic geothermal energy across a range of resource types by improving technologies, reducing costs, and mitigating barriers. Within GTO, the EGS Program actively pursues research, development, and demonstration projects to facilitate technology validation and deployment, reduce cost, and improve performance of EGS. Specifically, the economic viability of EGS depends on developing and improving enabling technologies and a detailed understanding of rock mass behavior and permeability enhancement. While achieving cost-competitive electricity generation from EGS is a long-term goal, in the near-term, research, development, and demonstration projects will move industry along the learning curve toward technological readiness.
Through the FY21 Wells of Opportunity (referred to as WOO going forward) FOA, GTO is soliciting geothermal and hydrocarbon well owners or operators with existing wells that are willing to partner with DOE to advance and test EGS technologies in-situ. These wells could be “idle” or currently used for injection, production, and/or monitoring. Due to the criticality of the technology prototyping and methodology testing phase of research and development in the innovation pipeline, this FOA focuses on active field testing, where the Federal government takes on the associated cost and risks.
- Topic Area 1 – Amplify (EGS Near-Field RD&D): This field validation effort will culminate in new power production, adding to the commercial viability of existing geothermal fields. The goal of Amplify is to illustrate that near-field and in-field EGS can be successfully deployed now as a result of recent technology advancements and that low permeability/underproductive wells near and in existing hydrothermal fields can be turned into valuable assets using EGS techniques.
- Topic Area 2 – ReAmplify (Geothermal production from hydrocarbon wells): The objective of this initiative is to establish the commercial viability of geothermal energy production from existing hydrocarbon fields. The goal of ReAmplify is to establish a pilot program where the production of geothermal heat from existing hydrocarbon fields can be demonstrated for electricity production or direct use applications.
Building a clean energy economy and addressing the climate crisis is a top priority of the Biden Administration. This FOA will advance the Biden Administration’s goals to achieve carbon pollution-free electricity by 2035 and “deliver an equitable, clean energy future, and put the United States on a path to achieve net-zero emissions, economy-wide, by no later than 2050“[6] to the benefit of all Americans. The Department of Energy is committed to pushing the frontiers of science and engineering, catalyzing clean energy jobs through research, development, demonstration, and deployment (RDD&D), and ensuring environmental justice and inclusion of underserved communities.
The R&D activities to be funded under this FOA will support the government-wide approach to the climate crisis by driving the innovation that can lead to the deployment of clean energy technologies, which are critical for climate protection. Specifically, this FOA focuses on critical aspects of reservoir management needed for widespread commercialization of EGS technologies which directly supports the Biden Administration’s goals for a clean energy future. In addition, this FOA provides an opportunity to reduce carbon emissions from the fossil fuel sector and facilitate clean geothermal energy/heat production from hydrocarbon wells.
[1] The GeoVision Roadmap outlines a compilation of technical, economic, and institutional actions that the entire geothermal community including DOE, other government agencies, industry, and academia must address in order for geothermal technologies to play a larger role in the Nation’s energy mix.
[2] Hydrocarbon: An organic chemical compound of hydrogen and carbon in the gaseous, liquid, or solid phase. https://www.eia.gov/tools/glossary/index.php
[3] Blackwell, D., Negraru, P., and Richards, M., 2006. Assessment of the Enhanced Geothermal System Resource Base of the United States. Natural Resources Research, Vol. 15, No. 4, December 2006. DOI: 10.1007/s11053-007-9028-7.
[4] Porro, C., Esposito, A., Augustine, C., and Roberts, B., 2012. An Estimate of the Geothermal Energy Resource in the Major Sedimentary Basins in the United States. GRC Transactions, Vol. 36, 2012.
[5] Zafar, S. and Cutright, B., 2014. Texas’ geothermal resource base: A raster-integration method for estimating in-place geothermal energy resources using ArcGIS. Geothermics, Vol. 50, April 2014.
[6] Executive Order 14008, “Tackling the Climate Crisis at Home and Abroad,” January 27, 2021.
Informational Webinar:
Please access the information webinar at: https://doe.webex.com/doe/j.php?MTID=ma57725545051bda39fd560f48a740371