Geothermal Energy Pros and Cons

While geothermal energy is being pitched as an apt replacement for fossil fuels, there are some people who are still skeptical about its efficiency. In such a situation, our best bet is to evaluate its pros and cons to see whether it has a bright future, or not.

According to the Geothermal Energy Association, the United States produces a whopping 15 billion kilowatt hours of power every year; that's equivalent to the amount of power produced by burning approximately 25 million barrels of oil.

Geothermal energy is the energy derived from the interior of the Earth, which is harnessed in the form of steam and used to generate power. Being cost-effective and environment friendly, it is being looked upon as an alternative source to replace the harmful fossil fuels, which are expected to exhaust sometime in the near future.

Several countries, including the United States, Philippines, Indonesia, Kenya, and Iceland have initiated projects to tap this energy stored beneath the Earth's crust. In fact, geothermal energy accounts for one-third of the total energy production in Iceland; a target which many other countries have their eyes on.

Geothermal power plants produce electricity by using geothermal dry steam, or hot water derived from the Earth. This steam, or water is accessed by a digging well and brought to the plant at the surface using specially designed pipes, where it is eventually used to rotate the turbines to generate electricity.

Basically, there are three types of geothermal power plants -
✦ Dry steam geothermal power plants, wherein the steam is directly brought to the plant through a pipe.
✦ Flash steam plants, wherein hot water is brought to the plant and sprayed into a tank in order to create steam.

✦ Binary cycle plants, which use moderately hot water derived from the Earth and mix it with some chemicals to form steam that is required to produce electricity.

Other than power generation, geothermal energy is also used for heating homes and backyard swimming pools in the United States.

As beneficial as it may seem, even geothermal energy has its share of restrictions, which have to be compared with its benefits to see whether it is actually as good as it is believed to be.

★ After it is produced, geothermal energy is absolutely non-polluting and therefore, is considered an environment friendly source of energy. Not just the energy, but even geothermal power plants are known to be environment friendly in nature.

A large part of the credit for this goes to the exclusion of fossil fuels from the process of generating electricity in these power plants.

★ Geothermal energy is a source of renewable energy, as it is entirely dependent on heat, which is produced within the Earth continuously. Unlike fossil fuels, which are expected to exhaust sometime in the near future, this source of energy will continue for a long time ... as long as the Earth's core continues to radiate heat to be precise.

★ Geothermal power plants are baseload, i.e., they work continuously for 24 hours a day and 365 days a year.

This gives it an edge over solar energy, which only works for a part of the day, or year, and wind energy, which is dependent on weather. These power plants also make optimal use of land, which is not the case with solar, or wind energy, wherein vast area is required.

★ Geothermal power plants have a low operational cost, i.e., they don't require much funding for operations once they are established. Even geothermal heating systems are considered 45 percent more efficient than their traditional counterparts. If geothermal energy is pitched as an apt replacement for harmful fossil fuels today, it is because of all these pros that it boasts of.

★ While these positive points look quite impressive, one can't ignore the negatives of this source of energy. To start with, one of the major problems with geothermal energy is that of availability. Geothermal energy can only be tapped -- to its full potential -- in certain regions on the Earth.

More importantly, most of these regions are located away from the human settlements, which in turn, adds to the overall expenditure in the form of transportation cost.

★ Though it is widely promoted as a cheap source of energy, the initial cost of setting up a geothermal plant can be enormous. It is because of this high expenditure in the initial phase that most of the countries have refrained from opting for it.

★ More importantly, there is no guarantee that the site being drilled will facilitate access to steam, or hot water forever, or that the site in which one has invested will continue to provide steam, or water in desired amounts.

If the site runs out of steam, which can and has happened in several places in the past, it will result in heavy loss for the company.

★ Then there are more serious issues, like that of harmful emissions and earthquakes. In fact, geothermal plants have been long associated with low-magnitude earthquakes, which can damage standing structures in the long run. 

Such seismic activity is usually attributed to the process of injecting high-pressure streams in the Earth's crust. In some regions, the process has also been linked to subsidence, i.e., sinking of land.

★ As for harmful emissions, some plants are known to emit very small amounts of sulfur dioxide, hydrogen sulfide, and nitrous oxides, alongside water vapor (which is a greenhouse gas), though the amount is negligent as compared to emissions by fossil fuels.

Similarly, the water used in the process can be polluted by arsenic, or mercury if the system is not insulated properly; again not a serious issue, but worth giving a thought.

Now that it has been proved that it is feasible to generate electricity by harnessing geothermal energy, we have to put in some efforts to optimize the initial investment and make it an economically viable option. Success in these efforts will help us combine it with other alternative energy sources. This will put an end to use of fossil fuels and the pollution caused by them.