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Graphic by Jill Bergman.
Between local initiatives to implement clean energy in the Yampa Valley and a statewide initiative to increase use of geothermal run by the Governor’s office, geothermal energy has been in the news a lot lately.
But what exactly is it, and why do climate advocates support it?
The first thing to know is that geothermal is a safe and reliable clean energy source that makes sense for our region of Colorado. The word geothermal derives from the Greek words geo, for earth, and therme, for heat. This source of energy is renewable because heat is continuously produced within the earth.
Read on to learn the answers to some common questions about geothermal.
Is geothermal a reliable technology?
Geothermal for heating buildings has actually been in use since 1890. Geothermal used for electricity generation began in the 1960s in California. Originally, this technology had to be situated in the perfect place to take advantage of naturally occurring heated water and steam.
Diagram courtesy of the US Department of Energy. To learn more about geothermal, check out their guide at energy.gov/eere/geothermal/geothermal-heat-pumps.
Now, with technology developed for oil and gas extraction, we have the ability to drill to reliable heat sources underground that can generate consistent, clean energy. In addition to deep drilling, geothermal energy is now taking advantage of limited hydraulic fracturing, or fracking, but not to extract fossil fuels. This technique makes more porous space within rock underground. Water is injected, heated by the earth, and then pumped up to be used for electricity generation. The water can be used repeatedly with minimal loss.
Using the trained workforce and technologies developed by the oil and gas industry to instead increase the effectiveness of hydrothermal energy makes these enhanced geothermal systems very reliable.
Isn’t geothermal just used for heating?
Geothermal energy is used for heating buildings, but it can also be used to cool them in the summer. It is also used on a utility scale to generate electricity.
Geothermal heat pumps use the temperature of the ground (at 30 feet down it is usually between 50°F and 59°F) to adjust the temperature of circulating water. In the summer it is cooler underground than the air outside, and in the winter, it is warmer underground than the air outside, so heat pumps can work to heat or cool. In the winter, warmth from the collector’s fluids heated underground is concentrated and used to warm air that is then distributed through ducts to the rooms.
Diagram courtesy of the US Department of Energy. To learn more about geothermal, check out their guide at energy.gov/eere/geothermal/geothermal-heat-pumps.
In addition to heating and cooling buildings without using natural gas, heat underground can become the source for pressurized water or steam driving turbines to generate electricity without burning fossil fuels. Geothermal power plants can be situated in so many different places because of modern drilling technology, which makes them an excellent source of dependable, 24/7, clean, renewable electricity.
Can geothermal energy only be developed in limited places with hot water sources directly underground?
Geothermal energy can be accessed using different techniques in a wide range of areas. Natural reservoirs of hot water that travel through fractures in rock to come to the surface and create hot springs or vent steam are called natural hydrothermal resources. These areas are great places to locate hydrothermal power, but are limited and mostly located in the Western states.
“Now is a critical time to share your support for clean energy at Hayden Station, because the Colorado Public Utilities Commission (PUC) is hearing public comments on how a just transition plan from Xcel Energy can best honor our region’s history as an energy producer. Click here to learn how to make a comment to the PUC.
Enhanced geothermal systems to be used for electricity generation can be located almost anywhere by creating man-made reservoirs underground. Water is injected to heat among the hot rocks under the earth’s surface. For electricity generation, the hot water is drawn up through a well and pressure or steam drives a turbine and produces electricity.
For a geothermal heat pump in a building, water cycles through an underground pipe system to exchange heated or cooled water with a heat pump water source. This water then heats or cools the air of a building to be distributed through ductwork. It can also be sent through hydronic piping, a type of plastic pipe that can safely contain hot or cold liquid. This system doesn’t need the deep wells used for electricity generation, and the fluid remains contained, so it’s not dependent on natural hydrothermal locations. For these reasons, geothermal heat pumps aren’t restricted to certain locations.
Geothermal in Hayden
Here in Routt County, as Hayden Station transitions away from the use of coal as an energy source, geothermal could play a vital role in providing clean energy and economic development in the region.
Hayden Station. Photo by Jeffrey Beall, Wikimedia Commons.
Yampa Valley Sustainability Council (YVSC) supports the implementation of geothermal energy at Hayden Station to assure continued benefits to workforce and community needs. To learn more about YVSC’s stance, read the column from Michelle Stewart, Ph.D., YVSC’s executive director, here.
Now is a critical time to share your support for clean energy at Hayden Station, because the Colorado Public Utilities Commission (PUC) is hearing public comments on how a just transition plan from Xcel Energy can best honor our region’s history as an energy producer. Click here to learn how to make a comment to the PUC.
