Geothermal energy is one of the most popular alternative energy sources available, despite the fact that you may not have heard much about it. It is a clean, sustainable energy source that will endure for a very long time. The source of geothermal energy, however, is unknown.
The earth itself holds the key. The term “geothermal” is derived from the Greek words “geo” and “therme,” which both mean “heat.” Geothermal energy basically heats energy that is drawn from the Earth itself.
The source of geothermal energy will be discussed in this article. Please keep reading.
Where Does the Heat for Geothermal Energy Come From?
The Earth’s core itself generates geothermal heat. You might not think that energy, when compared to the sun, is much, but you would be mistaken in some ways. It is 11,000 degrees just at the Earth’s core.
That is warmer than the sun’s surface. The decay of radioactive materials in the Earth’s core and in the rock layers that surround it produces geothermal energy.
But this still doesn’t explain how this energy can be accessed. Even with the most advanced technology, 11 km is about as deep as mankind can go.
Plate tectonics is the answer. The boundaries and faults are cracks in which magma rises close to or to the surface of the Earth’s crust. This fact is utilized by geothermal plants, which use the heated water generated by volcanic activity to generate electricity.
Further Reading: Fun Facts About Geothermal Energy You Don’t Know
Why Do We Use Geothermal Energy?
- It is renewable — With the right management, the rate of energy extraction and the rate of natural heat recharge from a reservoir can be balanced. Read Is Geothermal Energy Renewable Or Nonrenewable?
- It is reliable — No matter the weather, geothermal power plants reliably generate electricity while operating around the clock, seven days a week. Additionally, compared to coal, natural gas, nuclear power, or large hydro stations, it has the capacity to produce more electricity over the same time period.
- It has a small footprint—Geothermal power plants are small and require less land per GWh (404 m2) than coal, wind, or solar PV with the center station (3642 m2, 1335 m2, or 3237 m2, respectively).*
- It is clean — There are no greenhouse gases released by current closed-loop geothermal power plants. In comparison to the majority of conventional generation technologies, geothermal power plants use less water overall over their lifetime energy output.
- It is versatile – You can drill for heat directly or integrate the useful byproduct heat produced by geothermal power plants with greenhouses, fish farms, and food processing.
Here are the Pros And Cons of Geothermal Energy.
How Geothermal Energy is Captured?
Geothermal Springs for Power Plants
Currently, the most common way of capturing the energy from geothermal sources is to tap into naturally occurring “hydrothermal convection” systems, where cooler water seeps into The heated crust of the Earth and rises to the surface.
It is relatively easy to capture that steam and use it to power electric generators once this heated water has been forced to the surface. For better steam capture, geothermal power plants create their own holes in the rock.
The three main types of geothermal power plants all draw hot water and steam from the earth, use it, and then recirculate it as warm water to extend the life of the heat source.
The simplest configuration, known as dry steam, involves passing steam straight through the turbine before it enters a condenser to be converted to water. In a second approach, very hot water is depressurized or “flashed” into steam which can then be used to drive the turbine.
The third method, known as a binary cycle system, involves passing hot water through a heat exchanger to heat a second liquid, like isobutane, in a closed loop.
Since isobutane more readily turns into steam to power the turbine and boils at a lower temperature than water, it is preferred. The following diagrams display these three systems.
The resource determines which design should be used. It can be used immediately, as in the first design, if the water emerges from the well as steam. A flash system can be used if the hot water is hot enough.
It must pass through a heat exchanger if not. There is more room for growth in the binary cycle, heat exchanger design because there are more hot water resources available than pure steam or high-temperature water sources.
Direct Use of Geothermal Heat
Additionally, geothermal springs can be used directly for heating. Geothermal hot water is used for a variety of purposes, including heating buildings, growing plants in greenhouses, drying fish and crops, de-icing roads, enhancing oil recovery, assisting in industrial processes like pasteurizing milk, and heating spas and water at fish farms.
The geothermal water has been used to heat homes and structures for more than a century in Boise, Idaho, and Klamath Falls, Oregon. Warm Springs, Virginia, a town on the east coast, uses springs to heat one of the community resorts and also gets its heat directly from the water.
Almost all of Iceland’s buildings use hot spring water to heat them. In actuality, geothermal sources provide more than 50% of Iceland’s primary energy.
For instance, in Reykjavik (population 118,000), hot water is piped in from a distance of 25 kilometers, and locals use it for heating and hot tap water.
Ground-source Heat Pumps
Geothermal heat pumps are a much more traditional way to use geothermal energy to heat and cool buildings. They utilize the constant year-round temperature of about 50°F that is only a few feet below the ground’s surface, also known as ground-source heat pumps.
Pumped through underground pipes and circulated back into the building is either air or antifreeze liquid. The liquid transfers heat from the structure to the ground in the summer. In the winter, it performs the opposite, supplying the building’s heating system with pre-warmed air and water.
The simplest form of ground-source heating and cooling involves a tube that enters a building’s ventilation system from the ground and the outside air. Compressors and pumps, like in electric air conditioning systems, are used in more complex but more efficient systems to maximize heat transfer.
Further Reading: How Efficient Is Geothermal Energy?
Conclusion: The Future of Geothermal Energy
Finally, geothermal energy is still among the world’s top sources of clean energy. More homes will be able to use this renewable energy source as access to it becomes easier thanks to advancements in technology.
Geothermal energy has the potential to significantly contribute to the transition of the United States (and other nations) to a cleaner, more sustainable energy system. One of the few renewable energy technologies that can deliver baseload power on a constant basis.
Furthermore, unlike nuclear and coal-fired power plants, binary geothermal plants can be used as a flexible source of energy to balance the erratic output of renewable resources like wind and solar.