Geothermal Energy–Earth’s Sustainable Heat Source

Did you know that below the earth’s crust is a powerful, renewable source of heat energy? Way down in the earth’s core, 4,000 miles below the crust, temperatures rise higher than the surface of the sun. Geothermal comes from two greek words: geo (earth), and therme (heat). It makes sense that geothermal energy is simply heat generated within the earth. You can see evidence of geothermal energy rising to the surface if you visit an active volcano, geyser, hot spring, or fumarole.

Harnessing this source of heat energy is as easy as drilling a well to reach hot water and steam for use in producing energy. Like any energy source, there may be advantages and disadvantages, but the use of geothermal energy dates back to antiquity. Many ancient cultures have used hot springs for bathing, cooking, or heating, such as the ancient Romans, Native Americans, and the Chinese.

Today, there are two general applications to make use of geothermal heat. The first, geothermal heat pumps, need only reach to the first 10 feet under the Earth’s crust. What’s advantageous of the temperature here is that it is consistent, rarely wavering from a range of 50 to 60 degrees Fahrenheit. During winter months, heat from underground, which is warmer, can be pumped to a building. In summer months, the same technology can be utilized to pump in cooler air. All that is required for this geothermal application is a heat pump, pipes, and duct work.

The second application involves wells to hot water or steam below the Earth’s surface. By drilling into hard rock, steam or heat is generated that can provide power. This is also a way to reach hot water near the surface that pools beneath the crust, which can be pumped to nearby buildings for heat.

The greatest benefit of geothermal energy is its environmental impact, or lack thereof. There is little or no impact, because the Earth never stops heating. This makes the energy renewable and sustainable. After water and steam from geothermal reservoirs has been used, it can be injected back into the earth for reuse.

Geothermal power plants give off relatively low emissions because no fuel is burned to generate electricity. In fact, compared to a fossil fuel plant, geothermal plants release less than 1 percent less carbon dioxide emissions and 97 percent less acid rain. Although hydrogen sulfide is found naturally in the hot water and steam, scrubber systems are utilized in geothermal plants to clean the air of this compound.

There are also a few disadvantages. One is the corrosiveness of the fluid itself. In comparison to steam boilers, the temperature reached by geothermal power is lower. This means that the power needs to be used quickly and efficiently. Also, toxic metals or chemicals such as mercury or arsenic can be found in trace quantities in geothermal water. For this reason, it can never be disposed of in natural waterways.

Despite the few disadvantages, geothermal power plants are becoming more widespread. There are 33 areas in California and 14 in Nevada utilizing geothermal energy. Direct use heating applications and power plants run by geothermal power are efficient and eco-friendly, and usage in the future may grow exponentially with no adverse impact to our planet.