The temperature of the earth’s core is estimated to be somewhere around 6000 degrees Celsius (about 10,800 degrees Fahrenheit.) As this massive amount of thermal energy radiates out through the Earth, rocks and underground reservoirs are heated. These resources can then be tapped in order to generate electricity, bringing with it a number of advantages and disadvantages.
In this article we’ll take a look at the many different advantages and disadvantages of geothermal energy, weighing up the pros and cons to determine how beneficial geothermal energy is to the world.
Advantages of Geothermal Energy
There are numerous benefits associated with the use of geothermal energy, many of which are explained below.
1. Renewable and Sustainable
Geothermal energy is both renewable and sustainable. The thermal resources of the Earth will never run out and will be around for as long as the Earth is inhabitable.
2. Environmentally Friendly
Geothermal energy is an environmentally friendly energy source when compared with fossil fuel alternatives such as coal, oil and gas. The process of producing electricity from geothermal energy has a much lower impact on the environment than these alternatives.
3. Constant Supply
Unlike other renewable energy technologies (such as solar and wind power), geothermal power can provide a constant, uninterrupted supply of electricity. Solar panels can only produce electricity during the day and wind turbines only produce power when there is enough wind.
The benefit of constant supply makes Geothermal energy a far more predictable means of generating electricity when compared to its renewable energy rivals.
4. Small Footprint
Compared with more mainstream power plants (such as coal, oil and nuclear power plants), geothermal power plants require a relatively small amount of space. Although a geothermal power plant will reach depths where a sufficient level of geothermal energy is stored, its land footprint will be small.
Geothermal power is considered to have one of the smallest surface land footprints per kilowatt (kW) of all the power generating technologies in use today.
5. Cost Effective
Although geothermal power can only be generated in specific areas, installations in those areas are considered highly cost effective. Electricity generated by geothermal power stations is considered to be one of the cheapest power sources in use today.
6. Low Maintenance
Although the initial cost of geothermal power plants is considerably high when taking into account the investment required for exploration, drilling wells and plant installation, once these plants are built, they are considered to be very low maintenance when compared with other mainstream power plants that produce their electricity from other sources (such as coal, oil and nuclear.)
7. Low Noise
Generating electricity from geothermal energy is a relatively low noise process. Once a geothermal power plant is built, the main source of noise comes from fans contained in its cooling systems. Generator houses will often feature noise dampening materials to minimize exterior noise.
8. Reduces Fossil Fuel Dependency and Increases Energy Security
Geothermal energy cuts our dependency on fossil fuel alternatives, helping to provide stable electricity costs that are unaffected by fluctuations in the price of fossil fuel reserves. This advantage is also associated with most other renewable energy sources.
In addition to helping to reduce fossil fuel dependency, geothermal energy can also help to increase energy security for some nations. In countries where geothermal energy is a viable means of generating electricity, a significant proportion of that country’s energy demands can often be met by the use of geothermal technologies. This reduces the need to obtain electricity or natural resources from other countries, thus helping to increase energy security.
9. Job Creation
Geothermal energy not only provides a source of clean and renewable electricity, it can also provide numerous benefits to the economy of a particular country, through aspects such as job creation.
According to a 2014 report from the International Renewable Energy Agency (IRENA), the geothermal industry supported 35,000 American jobs between 2012-2013 (both direct and indirectly.)
10. Huge Potential
Although geographical limitations exist when it comes to geothermal energy technologies, this power source has massive potential. A recent study by the Geothermal Energy Association (GEA) estimated that just 6.5% of global geothermal energy potential has been tapped so far. The Intergovernmental Panel on Climate Change (IPCC) have even estimated total global geothermal power potential to be in the range of 35 gigawatts (GW) to 2 terawatts (TW.)
Disadvantages of Geothermal Energy
Although the advantages of geothermal energy are considered to greatly outweigh the disadvantages, geothermal energy still has its drawbacks, many of which are explained below.
1. Geographical Limitations
Geothermal energy is arguably the most location specific energy source known to man. Geothermal activity is at its greatest along tectonic fault lines within the earth’s crust and it is in these areas where geothermal power plants are considered to be most effective.
The United States, Iceland, Kenya, Indonesia, Philippines and Mexico have all found success in generating significant levels of electricity from geothermal energy resources.
2. Large Investment Needed
The upfront investment that is needed for a geothermal power plant is considerably high when compared with the investment required for power plants that produce electricity from other resources such as coal and oil.
A large proportion of this cost is associated with the exploration and drilling for geothermal energy resources, two processes that don’t affect traditional power stations. However, it is quite safe to say that if we take into account the exploration and mining costs of fossil fuels (required for traditional power stations to function), then geothermal power would be considered the cheaper option.
3. Environmental Impacts
When looking at the disadvantages of geothermal energy, there are various environmental impacts that should be noted.
Below the earth’s surface lies an abundance of gases that are harmful to the environment and our atmosphere. During the production of geothermal power, gases can be released into the atmosphere. These gases include; hydrogen sulfide (H2S), carbon dioxide (CO2), ammonia (NH3), methane (CH4), and boron (B), some of which can contribute to global warming.
Water quality is also considered an environmental impact of geothermal energy. Chemicals used at some geothermal power plants have the potential to pollute the water table should any leakage occur. Although technology exists for the safe, nonpolluting use of geothermal fluids, there is always the potential for leakage to occur.
Although there are numerous environmental factors to consider, when compared with fossil fuel alternatives, geothermal energy is one of the most environmentally friendly energy sources available today.
4. Sustainability Concerns
Although geothermal energy itself is considered highly sustainable, there exists a sustainability concern associated with how we use it. Studies show that without careful management of geothermal reservoirs, they can become depleted, rendering a geothermal power plant useless until the reservoir recovers.
With the advancement in geothermal energy technologies, this sustainability concern is becoming less of an issue. Efforts are now made to inject geothermal fluids back into reservoirs as soon as the thermal energy has been utilized, thus reducing the chance of a well becoming depleted.
5. Seismic Instability
Earth tremors have been linked to the use of geothermal energy technologies in various parts of the world. Although often minor, these earthquakes have been known to cause damage to buildings, as was the case in Basel, Switzerland in 2006 when a geothermal exploration project was blamed for a series of earthquakes, some measuring up to 3.4 on the Richter scale.
A further study in 2011 of earthquakes in the area around the Salton Sea geothermal field in the United States found a strong correlation between geothermal exploration and seismic activity.