Geothermal energy is not new. In a very strong sense, prehistoric people who used caves or dug their homes into hillsides were using geothermal energy. Once you are below the frost line, which will vary by location, the Earth tends to maintain a stable temperature between 50 to 70 degrees Fahrenheit.
For example, if you enter a natural cave in central Missouri, in the United States, the temperature will be a steady 65 degrees Fahrenheit. This makes “spelunking”, the amateur version of speleology, a popular sport with many college students, in spite of the inherent dangers of underground activity.
With the exception of wet or rainy seasons, you can count on a consistent environment for learning about the Earth, endangered species, and just testing your physical prowess.
Geothermal energy is considered to be one of the cleanest, most environmentally friendly ways to heat and cool homes, as well as to produce electrical energy. But, in the words of the younger generation, it might be best to consider geothermal as “clean-ish” and “friendly-ish”.
There are good reasons why geology instructors sometimes encourage students to take part in official, well-run speleology clubs. The world beneath the Earth’s crust is more delicate than we realize.
Geothermal Energy Pros and Cons
Looking at the Good Stuff
- Nature’s Bounty
For communities that live near hot springs and other naturally occurring outpourings of geothermal energy, harnessing that free energy makes good sense.
Steam or water can be captured at the natural site, and put to work turning steam turbines that create electricity or that provide natural hot water. For centuries, the Japanese have capitalized on natural hot springs for healthful mineral soaks, as have other locations where naturally heated water bubbles to the surface.
- Making it Work
You don’t have to live near old Faithful or settle on the side of a volcano to use solar energy. Just as our ancestors used the steady underground temperatures to preserve food, our modern engineers have discovered how to use those temperature differences to our advantage.
By drilling down into the Earth or by digging a deep trench, pipes can be laid that will carry liquid through that steady temperature zone. By using heat-pump technology, the warmed liquid can be pulled up from the Earth, have pressure added to increase the temperature, and then the resultant cooled liquid returned to the Earth.
In summer, the process can be reversed and used to cool and area. This same process can be used on an industrial level to power turbines that make electricity.
- No burning of fossil fuels
- Minimal waste
- Almost no pollution
- Extremely cost-effective
- Minimal maintenance
And…the Not So Good Stuff
- It Costs a Lot
It has often been said that “there ain’t no such thing as a free lunch.” This is definitely true when it comes to geothermal energy, whether using it actively or passively. Unless you have the good fortune to live near a steam vent or on top of a cave, excavation is going to be essential. In addition to hiring earthmovers, geothermal is an equipment-heavy process. A simple home system begins at around $30,000.
- It Affects Aquifers
Drilling into the Earth often means encountering water reservoirs. In many active geothermal systems, water is pumped up out of the Earth and then pumped back in. If not carefully managed, this process can deplete important water reserves. It also carries the potential for polluting the water if the system is not well maintained.
- Pollutants Are Sometimes Released
There are a lot of different things underground, and not all of them are sweet and friendly like cave crickets or blind salamanders. Sometimes drilling can release sulfur, heavy metals (not to be confused with the band) and similar things. The good news here is that the contaminants released through geothermal energy activities are infinitesimal compared to the burning of fossil fuels.
- The Earth Moves
Poorly planned, extensive geothermal systems have the potential to destabilize the Earth. This can result in subsidence, mudslides, and even earthquakes if the operation is not well-planned.
Vertical vs. Horizontal
As previously noted, there is a lot of digging or drilling involved with setting up a geothermal system. As far as your local ecosystem is concerned, a horizontal system is probably the easiest and most economical to set up. It minimizes deep disturbance of the Earth. It can even be set up with an existing body of surface water, such as a pond or small lake.
The disadvantage to a horizontal setup is that it requires quite a bit of land and it will definitely disturb any established landscaping. Therefore, it is best done when building new construction. However, that doesn’t mean that you can’t retrofit an older home. Just be prepared for portions of your area to look like a lunar landscape for a while.
Drilling down avoids some of the landscape disturbance and takes up less horizontal space. It requires a good engineer who understands your environment and is dedicated to helping you make sure that everything will run smoothly with minimum impact on the earth below your establishment. It is actually an easier choice for older homes because it requires less digging.
It also works well for homes that are in subdivisions or similar areas where existing substructures might need to be considered. Going with geothermal gives whole new meaning to “call before you dig.”
Correctly set up, geothermal energy or heating/cooling is highly efficient and cost-effective. It can easily cut 30% off most electric bills. However, you will want a good engineer who plans carefully because low impact doesn’t mean no impact on the environment. Furthermore, you will want a company that is going to be around for a while because low maintenance doesn’t mean no maintenance. Keeping your equipment in good shape is essential to efficiency.
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