Geothermal Energy Gaining Momentum

May 28, 2009 · Filed Under Geothermal

One of the lesser known renewable energy sources, but growing is geothermal energy.  Congress and the Obama administration are taking efforts to make sure that America expands its use of this “undervalued” renewable resource.

Linux Geothermal Borehole
Photo by lydur.

What is Geothermal Energy?

Many have probably heard the term geothermal being used, but may not know exactly what it is and how it is considered a renewable energy source.  The word geothermal itself literally means “earth heat” and is the energy extracted from heat stored within the earth. The earth’s crust holds in the heat within the earth and the only way to access this heat is to drill into the earth.  In order to actually get electricity from geothermal energy, it require high temperature water or steam.  There are actually three main uses of geothermal energy:

  1. Direct Use: Using host water from springs or reservoirs near the surface.
  2. Electricity Generation: Power plants require water or steam at very high temperatures.  Geothermal power plants are generally built where geothermal reservoirs are located within a mile or two fo the surface.
  3. Geothermal Heat Pumps: Use stable ground or water temperatures near the earth’s surface to control building temperatures above ground.

Geothermal is nothing new as it has been used for centuries because of how much heat is harnessed within our earth.  Hot springs are a great example of how geothermal energy is harnessed naturally with no drilling.  At the moment, geothermal meets about .3% of the total energy needs globally and is increasing every year.

Advantages

What makes geothermal power a renewable energy source is that it requires no fuel, but uses a constant flow of heat from the earth. It is a long-lasting energy source in which we already have technologies available to access the heat within our earth.  The power plants associated with generating electricity are far less expensive than coal or nuclear plants, create no pollution besides the above concern over CO2 leakage and are relatively small.  The cost will also stay down during the long run because there are very few expenses involved in running these plants.  Though there are some disadvantages to uses geothermal energy, the advantages far outweigh any negatives it may have.

Disadvantages

The biggest problem with this type of energy is the drilling and extraction process, both of which can have economical and environmental issues.  Years of research are put into surveying the particular piece of land to possibly drill and can often lead to negative results.  It also requires a large upfront cost (as much as $5 million) to drill deeply into the earth and even after a successful drill, it can be a hit-or-miss situation.  After extracting for years, a source can sometimes stop producing steam for many year, sometimes for as many as 10.  If there is a successful drill though, no additional fuel costs are required and can power an entire city off of a single plant.  There are also concerns about greenhouses gases that are emitted through the holes drilled within the earth that include CO2 and hydrogen sulfide.  These emissions are often controlled by the plant and are only a small percentage as compared to what traditional fossil fuel plants emit.

Expanding Geothermal

There are over 200 million acres of land in the West that are great candidates for geothermal drilling.   The government is doing its part by providing a $400 million bill to help generate more interest in the geothermal energy market.  The government has made a more streamlined process to allow for getting geothermal permits on federal lands much easier.  All that is required now is for the drilling to begin and it has.  There is no reason that geothermal should not be one of the top energy sources used throughout the world in the future.  It’s clean, extremely inexpensive to maintain and very little impact on the environment.  A truly renewable energy source.

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