A geothermal power plant uses its geothermal activity to generate power. This type of natural energy production is extremely environmentally friendly and used in many geothermal hot spots around the globe.
To harness the energy, deep holes are drilled into the earth (much like when drilling for oil) until a significant geothermal hot spot is found. When the heat source has been discovered, a pipe is attached deep down inside the hole which allows hot steam from deep within the earth’s crust to rise up to the surface.
The pressurized steam is then channeled into a turbine which begins to turn under the large force of the steam. This turbine is linked to the generator and so the generator also begins to turn, generating electricity. We then pump cold water down a new pipe which is heated by the earth and then sent back up the first pipe to repeat the process.
The main problems with geothermal energy is that first, you must not pump too much cold water into the earth, as this could cool the rocks too much, resulting in your geothermal heat source cooling down too fast. Secondly, geothermal power plants must be wary of escaping toxic gases from deep within the earth.
A very good way of thinking about geothermal energy is remembering that all our continents lie on molten rock deep within the earth; this rock produces tremendous levels of heat that we are able to extract, just think of your nation lying on a bed of fire. Geothermal power is one of the most renewable energy sources that exist on our planet today; the earth will contain this heat for our lifetime. If this heat disappears, our planet will become too cold to survive on.
You can purchase small scale geothermal equipment for your home yet this works in a different manner to geothermal power stations. The power stations extract the heat directly from deep within the earth, whereas home geothermal hot water equipment absorbs heat over a lengthy period of time from a few meters beneath your feet.
Here we shall discuss the different disadvantages of geothermal energy.
Geothermal heat is extracted from deep within the earth’s surface, and this is the main disadvantage concerning finding a suitable build location, so, the main disadvantage of building a geothermal energy plant mainly lays in the exploration stage. During exploration, researchers will do a land survey (which may take several years to complete) and then provide their findings to the company that contracted the survey.
Many companies who order surveys are often disappointed, as quite often the land they were interested in cannot support a geothermal energy plant. To extract the heat we have to find certain hot spots within the earth’s crust, these are very common around volcanoes and fault lines, but who wants to build their geothermal energy plant next to a volcano?
Some areas of land may have the sufficient hot rocks to supply hot water to a power station, but what if these areas are contained in harsh areas of the world (near the poles) or high up in mountains. Some very good proven spots have been found in New Zealand, Iceland, Norway and Sweden.
The questions that are usually asked during a survey are; is the rock soft enough to drill through, do the rocks deep down contain sufficient heat, will this heat be sustainable for a significant amount of time, is the environment fit for a power plant. If the answer to these basic questions is yes, a more in depth survey should go ahead.
Another big disadvantage of geothermal energy extraction is that in many cases, a site that has happily been extracting steam and turning it into power for many years may suddenly stop producing steam. This can happen and last for around 10 years in some cases.
Developers of such sites must be careful and aware that in some cases, harmful gases can escape from deep within the earth, through the holes drilled by the constructors. The plant must be able to contain any leaked gases, but disposing of the gas can be very tricky to do safely.
Theodore Sumrall is a former Professor of Engineering and is the Chief Scientist for The Institute for Energy Independence