Sunset over a U.S. Department of Energy geothermal test site (Naval Air Station Fallon in Nevada). ... [+] Photo credit: Dick Benoit
The Biden Administration – due to take office January 20th, 2021 – is expected to turn political rhetoric into political action when it comes to the nation’s resource use and energy management. Central to this will be decarbonizing the US electricity sector through renewable power sources as part of the much-touted green energy transition.
Yet, it needs to be done responsibly and rationally. Wind and solar power are the global rock stars of the clean energy stage. While market forces are a major driver of renewable adoption in the US, state, local, and federal policies such as mandated Renewable Portfolio Standards (RPS) and green subsidies are also boosting the proliferation of these carbon-free technologies. In fact, the power generated from renewables surpassed that of coal in 2019. And in 2021, investment in new renewables projects will outpace their hydrocarbon competitors. But amidst this green growth in the power sector, there are other low-emission renewable energy sources (RES) that should not be overlooked. Geothermal energy is one of these viable technologies.
Geothermal energy extracts heat from the earth’s crust to turn water into steam. It is one of the renewable energy sources that can provide clean electricity as well as heat for ‘direct use.’ Geothermal energy has the advantage of a high capacity factor compared to intermittent RES, and thus is a good source of affordable and clean baseload electricity.
There is a catch, however. Geothermal plants must be constructed in specific tectonic hotspots to be financially viable.
Countries like Iceland, Kenya, Indonesia, El Salvador, Turkey, and New Zealand are well suited for this technology due to their favorable seismic zones and continental rifts. The United States is also home to a number of geothermal ‘hotspots.’ In fact, this country boasts the largest geothermal installed capacity in the world with 3.7 Gigawatts. But that’s not enough.
The majority of the US geothermal energy is located in the Mayacamas Mountains and Imperial Valley of California, as well as in Western Nevada. In power generation, geothermal energy has four conventional forms of production: dry steam plants, flash plants, binary cycle plants, and combined cycle plants – all of which are dependent on the heat, fluid, and permeable substrate that are naturally available in the earth’s surface. This form of power generation is also called hydrothermal electricity generation.
In addition to conventional geothermal energy, the field is preparing for a new technology that is expected to be more commercially viable and less location specific: Enhanced Geothermal System (EGS). The Department of Energy (DOE) describes EGS as a “man-made reservoir, created where there is hot rock but insufficient or little natural permeability or fluid saturation. In an EGS, fluid is injected into the subsurface under carefully controlled conditions, which cause pre-existing fractures to re-open, creating permeability.” The ability to tap into sub-surface heat from virtually any location is the Holy Grail of geothermal technology.
DOE
For the US, conventional geothermal energy currently makes up 0.4% of net electricity generation. The DOE projections suggest that with the use of EGS, there may be over 100 Gigawatts of geothermal electric capacity in the continental US, which would account for nearly 10% of current US electricity capacity and be 40 times the current installed geothermal capacity. The downside of this technology, and in fact any geothermal energy project, however, is that they require advanced engineering expertise and have high capital costs during the development phase (risks and costs generally increasing with depth and temperature). Additionally, similar to fracking, the application of EGS involves risks related to ‘induced seismicity’, or manmade earthquakes.
Geothermal energy could play a much larger role under the Biden Administration.
A study published by the U.S. Department of Energy last year highlights the “enormous untapped potential of geothermal” for the United States. The report, titled GeoVision: Harnessing the Heat Beneath Our Feet was also recently discussed at a virtual panel organized by the Atlantic Council this week, where the Department’s Assistant Secretary Daniel R. Simmons, from the Office of Energy Efficiency and Renewable Energy, underlined that “there is so much opportunity with the geothermal energy” and that in the next Administration, the DOE is seeking to continue the dialogue between the U.S. and other pioneering countries like Iceland and New Zealand to succeed in this field.
Indeed, geothermal has been on the DOE radar since the Obama years. In 2016, the Department announced a $29 million funding prize under the Frontier Observatory for Research in Geothermal Energy (FORGE) program for multiple EGS research projects at Sandia National Laboratories and the University of Utah.
In October of this year, FORGE Utah began drilling its first experimental EGS well using techniques similar to those seen in hydraulic fracturing. Per Joseph Moore, PhD, the Principal Investigator of Utah FORGE:
“The upper part of the well will be drilled vertically through approximately 4,700 feet of sediments at which point it will penetrate into hard crystalline granite. At about 6,000 feet (around 1,800 meters), the well will be gradually steered at a 5º angle for each 100 feet (30 meters) until it reaches an inclination of 65º from its vertical point. The total length of the well will be approximately 11,000 feet with the “toe” – or the end of the well – reaching a vertical depth of 8,500 feet (2,600 meters). The temperature at this depth will be 440 degrees F (around 270 degrees Celsius).”
Like the breakthrough hydraulic fracturing technology that was initially funded by the US government, EGS techniques require advanced engineering that – once developed – could have huge ramifications for the US energy industry, much like the Shale Revolution of the past decade. In the meantime, geothermal could create an opportunity for the now-debt-ridden shale industry to use its technical expertise in an area where it is “cool” to frack. Industrial leaders admit that a great deal of overlap exists in technical aspects between the O&G and geothermal sectors. With encouragement from an administration dead set on decarbonization, geothermal may bring good prospects to the gloomy US oil and gas sector.
With assistance from Talya Yuzucu