EDITOR’S NOTE: This is Part 1 in a three-part series on geothermal energy, its availability in the West and the implications in Greater Yellowstone.
As the land of fire and ice, Iceland is an arctic nation characterized by dynamic duality. With snowcapped mountain peaks stretching to an elevation of nearly 7,000 feet and ice flow-laden seas, Iceland, which measures roughly the size of Kentucky, holds a geologically rich power source: geothermal energy.
Today, the government of Iceland reports that geothermal power facilities generate 25 percent of the country’s electricity and nearly all of its domestic hot water.
Jason Kaiser, an associate professor of geology at Southern Utah University, notes that Iceland is a global leader in harnessing power and hot water through geothermal energy, partly due to its readily available resources. But in the United States, geothermal energy is concentrated in the West, where it is primarily located. And significant geothermal features exist in protected areas, such as Yellowstone National Park.
Large-scale geothermal energy harnesses power by taking advantage of natural heat sources found deep within the Earth’s crust, where hot water warms and seeps into underground reservoirs. When this water is hot enough, it can break through the Earth’s surface crust at specific regions, often where tectonic plates shift, producing hydrothermal features such as hot springs and geysers like Yellowstone’s Old Faithful.
Conventional geothermal energy has three key features: permeability in the bedrock, access to water, and shallow heat, all of which constrain where heat can be utilized from the Earth as a power source. Historically, geothermal energy was limited to areas of hot surface water, but now we can access this superheated water.
Modern technological advances today allow energy producers to drill as far as two miles below the Earth’s surface to access deep heat, which flashes hot water to steam at the surface, driving turbines and powering generators.
With low emissions, a small physical footprint, and around-the-clock power generation, experts like Kaiser say geothermal energy provides an opportunity to strengthen America’s energy grid, and while the number fluctuates “since new plants are being built all the time,” he estimates there are only around 31 geothermal power plants in the U.S.
Angela Seligman, senior geoscientist at the nonprofit environmental organization Clean Air Task Force, says geothermal energy in the U.S. is underutilized and underprioritized.
“It has not been put at the forefront for a long time in terms of an important source of electricity because, until recently, the focus has been on conventional geothermal energy,” Seligman said, referring to the latest advances in technology.
To date, most electricity from geothermal energy has come from conventional geothermal systems that rely on a shallow heat source, the permeability of the bedrock, and the ability to access and move water through the rock.
“When we have those three things together, we typically think of it as a conventional geothermal system, but there aren’t very many regions around the world that have those three features available and readily accessible,” she said.
In enhanced geothermal systems, drillers are now able to use advanced technologies to create fractures in hot, dry rock that may have previously been impermeable with older equipment, Seligman said, and pipe water into otherwise dry rock. The rock heats the fluid, generating electricity or to heat homes and businesses.
So, why isn’t the western U.S. producing more electricity through geothermal energy? Unlike Iceland, which has historically invested in infrastructure to support geothermal energy production, the U.S. power grid largely relies on natural resource extraction. According to the U.S. Energy Information Administration, fossil fuels generate 60 percent of U.S. electricity, whereas geothermal energy comprises just .4 percent. But that door may have recently cracked open.
It just might not be that easy.
Because America’s energy grid is based on fossil fuels, Kaiser says that to prioritize geothermal energy, new infrastructure would need to be built and existing infrastructure would need to be retrofitted.
“It’s pretty hard to retrofit, though not impossible, and it’s being done but [outdated infrastructure] is certainly a barrier we must overcome,” said Kaiser, adding that accessibility to geothermal features in places like the Rocky Mountains is complex and limited due to road access, weather conditions and proximity to the bigger electrical grid.
Most geothermal energy in the U.S. isare located in the western states, particularly in remote regions that are sparsely populated, such as the Greater Yellowstone Ecosystem. Compared to fossil fuels, geothermal energy resources are isolated by environmental conditions such as the inaccessible terrain of the Rocky Mountains. Coal and oil, conversely, can be mined from the ground and transported by truck or train to a power station that’s already connected to the power grid.
John Metesh, director of the Montana Bureau of Geology and Mines, has been working in the field for three decades and notes that over the last few years, the western U.S. has experienced significant growth in the geothermal sector.
“It’s always been there, but it really comes down to the economics,” he said. “Just like any other energy source, there has to be a market for it. But as the cost of energy goes up, the interest in green energy is, of course, increasing.”
The other part of the issue, however, is the generation. For geothermal energy to be commercially successful, it must generate electricity. Unlike fossil fuels, which can be transported to plants and converted into energy, geothermal requires electricity to be generated at the site, restricted to where it can be created.
“With geothermal, we have to produce the energy in situ,” Kaiser said. “The power plant has to be right where the heat source is, which means transmitting that energy could be a long way to the grid, and there is energy loss with transmission. So we don’t want to transmit [the power] very far to get it on the grid. That means updating the grid itself [and] adding a lot of infrastructure.”
Water access may also be a barrier. In the western U.S., many geothermal heat sources exist, but water is limited. To protect both, Kaiser warns developers to be careful if they’re disrupting the water systems and their aquifers.
“We have to make sure there’s heat there, but also that whatever aquifer we’re drilling into, we’re not disturbing it,” Kaiser said, adding that geothermal power companies must ensure enough usable, uncontaminated water in nearby aquifers to maintain equilibrium.
“For as much as we’re exploring alternative, renewable or green energy, we also have to be very, very careful with how we’re using our water in the western U.S.,” Kaiser said.
In interconnected environments like the Greater Yellowstone Ecosystem, the potential impacts of geothermal energy production may extend beyond the boundaries of a power production plant.
Click here to read Part 2 in our geothermal energy series, a historical look at how geothermal power extraction could impact surrounding features.
