In the 1970s, the United States focused on the potential of geothermal energy. Accordingly, we have several excellent publications on geothermal energy development. Following Congress’s passage of the Bipartisan Infrastructure Law in 2021, we see another potential geothermal renaissance in the United States. In 2023, the U.S. Department of Energy published an announcement to support $74 million to support enhanced geothermal systems pilot demonstration projects. According to the IEA 2020 U.S. Geothermal Report, the Bipartisan Infrastructure Law authorized the “DOE to support up to seven competitively selected pilot projects that collectively demonstrate EGS (enhanced geothermal systems) in different geologic settings, using a variety of development techniques and well orientations.”
As we enter this potential geothermal renaissance, we should revisit how the applicable law in the various U.S. jurisdictions determines who owns the heat and fluids in geothermal reservoirs.
US Geothermal Potential
With current technology, we can utilize geothermal energy as a critical part of the energy addition in the United States. The International Energy Association highlighted the 2050 geothermal energy potential of the United States in the aforementioned report:
- The United States remains the world’s leader “in installed geothermal capacity with approximately 3.673 gigawatts; this represents nearly 25 percent of the world’s total online capacity.”
- Geothermal energy only contributes less than 1 percent to U.S. energy capacity, with the potential to reach 8 percent by 2050.
- Geothermal heat pump installations increased at a 3-percent annual growth rate, and total facilities exceeded 1.7 million units in 2020, with 40 percent residential and 60 percent commercial or institutional installations with the most growth in the central and eastern states.
- The United States has a total installed capacity of 485 megawatts thermal for geothermal direct use and 20.7 gigawatts of installed capacity for geothermal heat pumps.
- The total estimated “U.S. geothermal power resource potential is approximately 530 gigawatts; estimated potential for direct use is 231 by 2050, including as many as 17,500 district heating and cooling systems.”
Geothermal Energy Benefits
Enthalpy, as defined by Merriam-Webster, is “the sum of the internal energy of a body or system and the product of its volume multiplied by the pressure.”
According to the Geothermal Energy Factsheet published by the University of Michigan’s Center for Sustainable systems, the Earth’s geothermal energy “exists in both high enthalpy (volcanoes, geysers) and low enthalpy forms (heat stored in rocks in the Earth’s crust).” High-enthalpy geothermal systems can generate electricity and low-enthalpy geothermal systems have the potential for heating/cooling residences in commercial, industrial and institutional facilities.
Geothermal energy provides a predictable and stable energy source. According to Geothermal Energy 101, Resources for the Future, Resources Magazine, “this quality renders geothermal energy a valuable baseload source of renewable power. A baseload power source can generate a set amount of electricity at any given time rather than producing varying amounts of electricity depending on external factors like the availability of wind and sun. At the same time, geothermal power plants offer more flexibility than some other types of baseload power sources, as it is relatively easy to ramp their power production up and down depending on need.”
Geothermal energy constitutes a low-emission renewable energy source. Some industrial processes could use geothermal energy as a viable substitute for higher-emission energy sources, and some industrial processes would require more effort to electrify.
Geothermal energy systems often maintain long operational lifespans. For example, geothermal heat pump equipment, generally, has a very long operating life for these heating and cooling systems. As stated in Geothermal Energy 101. the U.S. Department of Energy estimates that heat pumps generally operate for more than 20-year life spans and the associated “underground infrastructure can last up to 50 years.”
Geothermal Energy Challenges
There are, of course – as with any energy source – limitations, risks and challenges.
Geothermal energy utilization depends on the heat-generating potential of the Earth’s subsurface in a specific location. As a result, most of the electrical power generation potential in the United States has traditionally been in the higher-temperature subsurface regions found in the western United States. Newer technologies might open new geothermal energy opportunities in other parts of the United States.
Geothermal energy systems also pose a potential geohazard risk. Significantly enhanced geothermal systems utilizing large amounts of water in the subsurface geologic formations might spawn seismic events. Geothermal Energy 101 highlighted “the most recent illustration of this caution came in 2017 when the development of an EGS system in South Korea catalyzed a magnitude 5.5 earthquake. The risk of earthquakes can be diminished by strict standards; in the United States, where a well-established regulatory regime and a robust induced seismicity management protocol apply to geothermal development, earthquakes have not historically been a problem.”
And, there is the cost to consider. Geothermal Energy 101 emphasized that geothermal systems “are relatively costly to develop; capital cost estimates typically hover around $2,500 per installed kilowatt for larger facilities. For comparison, a simple natural-gas-fired plant hovers around $1,000 per kilowatt.”
However, the objective of recent federal legislation – the Infrastructure Investment and Jobs Act of 2021 and the Inflation Reduction Act of 2022 – is to lower the cost of geothermal energy systems by reducing regulatory costs and offering geothermal tax credits, thus making them more competitive with other traditional and renewable energy sources.
Likewise, the current geothermal energy renaissance in the United States might only reach the full potential envisioned by energy professionals, regulators, legislators, and stakeholders if the parties work together to enhance the benefits and overcome the challenges facing geothermal energy.