The United States has a renewable, 24/7 clean energy resource right beneath its feet that can be used for electricity generation and direct heating and cooling.
Geothermal energy is harnessed in geothermal power plants that run consistently no matter the weather conditions that typically restrict the use of solar or wind power. The lifecycle emissions of modern closed-loop geothermal plants are four times less than emissions from solar photovoltaic (PV) plants and six to 20 times less than natural gas, the U.S. Department of Energy says.
Despite these low-emission and 24/7 generation benefits, geothermal energy in the United States is an oft-overlooked resource by legislators and policy makers.
At the same time, research suggests that geothermal energy could be crucial to meeting the U.S. electricity needs with renewable energy only, one day, Grist’s Nathanael Johnson writes.
Yet, experts, think-tanks, and the U.S. government admit that there are both technical and non-technical barriers to wider industry adoption of geothermal energy resources.
Technical barriers include unlocking heat and very hot water from deep underground, often by taking a leaf out of the oil and gas fracking sector’s book, which leads to concerns about the hydraulic fracturing techniques and the risk that fracking rocks harder than the soft shale oil rocks could induce earthquakes.
On the other hand, lengthy permitting timelines have been identified as the primary non-technical barriers to geothermal project development.
No wonder then that despite its theoretically huge potential, geothermal energy is not a key energy resource in the United States.
Geothermal energy had one of the smallest shares of the U.S. electricity generation last year—just 0.4 percent in a fossil-fuel dominated electricity mix, where renewables including hydropower generated 17.1 percent of America’s electricity.
There are examples in the world that geothermal energy can make up much more of the energy mix.
In Iceland—a country with a population of just over 300,000 residents—geothermal power generates 25 percent of total electricity production, while nine out of ten households are heated with direct use of geothermal energy in district heating.
“Geothermal resources can be found nationwide, are “always on,” and represent vast domestic energy potential. Only a fraction of this potential has been realized due to technical and non-technical barriers that constrain industry growth,” the Department of Energy said in its new report ‘GeoVision: Harnessing the Heat Beneath Our Feet’ published last month.
According to the multiyear research collaboration that resulted in this report, technology improvements could reduce costs and risks associated with geothermal developments, potentially increasing U.S. geothermal power generation 26 times from today, to 60 gigawatts-electric (GWe) of always-on, flexible electricity generation capacity by 2050. This capacity would represent 3.7 percent of total U.S. installed capacity in 2050, and potentially generate 8.5 percent of all U.S. electricity, the report says.
Streamlining regulations and permitting would shorten development timelines, for example by “placing geothermal regulatory and permitting requirements on a level similar to that of oil and gas and other energy industries,” the analysis showed. Optimizing permitting alone could lead to more than double geothermal electricity generation compared to the ‘business as usual scenario’, according to the report.
A 2017 paper from the National Renewable Energy Laboratory argues that shortening the timeline by four years—for example by creating a centralized federal geothermal permitting office and using state permit coordination offices—could result in additional 2,529 MW of geothermal capacity by 2030 and 6,917 MW of geothermal capacity by 2050. This would be up by 116 percent compared to the expected geothermal capacity in the ‘business as usual’ scenario.
In the technical barriers to geothermal development, there is one common issue with the shale development in the U.S.—the seismic risks from fracking. In the so-called enhanced geothermal systems (EGS), fluid is injected to reach the abundant but stranded heat source. This can lead to earthquakes, as it happened in 2017 in South Korea, where a geothermal project triggered a 5.5 magnitude earthquake.
Discussing the earthquake in South Korea, Stanford geophysicist William Ellsworth said last month that “The potential for a runaway or triggered earthquake always has to be considered.” Yet, Ellsworth added that “if we can figure out how to safely develop power plants based on enhanced geothermal systems technology, it’s going to have huge benefits for all of us as a low-carbon option for electricity and space heating.”
By Tsvetana Paraskova for Oilprice.com
