Geothermal Energy – Pros and Cons

February 25, 2015 | 0

Geothermal energy refers to the power produced by using the energy present in the Earth’s crust. The energy present in the planet’s interiors is harnessed as steam which is then used to generate power. It is an environment friendly and cost-efficient way to produce power, and hence is regarded as an alternative energy source that can replace the hazardous fossil fuels. A number of nations across the globe, including the US, Indonesia, Iceland, Philippines, and Kenya have begun varied projects to harness the energy present within the Earth.

Working mechanism of geothermal energy plants

Geothermal power plants use hot water present in the crust, or geothermal dry steam, to generate electricity. The water or steam are brought to the surface of the earth near the power plants via deep wells that are dug into the earth and the use of uniquely designed pipes that draw out the steam. The steam then helps rotate turbines which in turn produces electricity. In addition to generation of power, geothermal energy is also used for heating pools and homes in the US.

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Geothermal power plants are of 3 basic types, as listed below:

  • Flash steam geothermal power plants. In this, the steam is created by spraying hot water into tanks present at the plant.
  • Dry steam plants. In this, varied pipes directly bring steam to the plant to produce electricity.
  • Binary cycle plants. These plants create steam by using a mixture of certain chemicals and moderately hot water harnessed from within the earth.

Geothermal thermal energy may seem a very good source of energy; but skim the surface and it does come with several disadvantages and restrictions. Some of the major pros and cons of geothermal energy are listed below.

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Pros of geothermal energy

  • Heat is being continuously produced in the Earth’s crust. Geothermal plants are completely dependent on this energy source for power generation. Thus, unlike fossil fuels which are most likely to get exhausted in the next few centuries, the earth is most likely to keep producing heat for many millennia to come. Geothermal energy can thus be regarded as a great source of renewable energy.
  • Due to nil use of fossil fuels during power generation, geothermal energy does cause any pollution or harm the environment in any way, during or after production. It is thus one of the best environment-friendly sources of energy. Even geothermal power plants are considered to be harmless to nature and environment.
  • The cost of operating geothermal plants is quite low. Most of the cost is related to construction and establishment of the plants; operating them hardly entails any cost.
  • Wind energy production is dependent on the prevailing weather conditions, while solar energy relies on the presence of sunshine. These energy sources can thus be harnessed under certain conditions and at certain times of a year. As opposed to this, geothermal power plants can work any time of the day or night, 24 hours a day and 365 days in a year. Also, unlike its environment-friendly renewable energy counterparts, geothermal power plants require less land for operations, thereby making them more efficient and optimal users of land.
  • Geothermal heating systems are also considered to be nearly 50 percent more effective and efficient as compared to the traditional home heating systems.

Cons of geothermal energy

  • Geothermal energy is widely considered as an inexpensive energy source. However, the initial costs, which includes search for sites rich in geothermal energy as well as the cost of setting up the plant, can be ginormous. It is one of the main reasons why many countries have not gone for this energy source.
  • Geothermal energy is not available everywhere. Its full potential can be tapped only at certain places on the planet. Also, a lot of these areas are isolated and distant from human settlements. Subsequent addition of transportation costs can then increase the overall cost of production.
  • There is no guarantee that the sites that are drilled for steam or hot water will have them or provide access to them. Also, there is no guarantee about the quantity of steam or hot water available/produced or its continuous supply. Thus, the investing company is at increased risk to suffering heavy monetary losses.
  • Some geothermal plants may emit minor quantities of harmful pollutants like hydrogen sulfide, sulfur dioxide, water vapor, and nitrous oxide; such emissions are however minimal as compared to fossil fuel emissions. Another minor environmental hazard is the fact that the water used for geothermal energy production may be contaminated with mercury or arsenic if the system is improperly insulated.
  • In addition to hazardous emissions, geothermal plants can also increase the risk to earthquakes, due to the process of injection of high-pressure streams into the planet’s crust. The plants are especially known to cause low-magnitude earthquakes, which in the long run can harm the structural integrity of skyscrapers and other standing structures. In some regions, geothermal plants have been thought to cause sinking of land or subsidence.
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