5 Disadvantages of Geothermal Energy Explained
Disadvantages of geothermal energy are; capital cost, geographic limitation, hazard risk, low mobility, and gaseous emissions.
This article discusses the disadvantages of geothermal energy, as follows;
1). Capital Cost (as one of the Disadvantages of Geothermal Energy)
The cost to produce geothermal energy is about US$ 1377 per kW, based on a range of US$ 1062-1692 /kW installed [5].
This means that several millions of dollars will be required for the installation of any functional geothermal power plant with usable capacity.
Capital costs within this range can be difficult to provide, for many aspiring users of geothermal energy, especially when it involves private or local installation schemes.
The cost of geothermal energy development comes mainly from preliminary activities like prospecting to locate hydrothermal resources, drilling, design and installation of geothermal pumps, among others.
At the point of use however, geothermal energy is low cost, compared to fossil fuels, nuclear and some renewable energy resources.
The cost effectiveness of geothermal energy makes it a fairly good investment, as geothermal heat is more consistent than solar and wind.
Difficulties of affordability for geothermal energy come at the point of system installation.
Also, hydrothermal energy resources that often act as carriers of geothermal energy, can decrease in volume and become depleted, so that although geothermal energy is renewable, its carriers can pose the risk of resource depletion.
To address the issue mentioned above, water from the surface is often circulated through geothermal reservoirs, and this further adds to the operational cost.
2). Geographic Limitation
Geothermal energy is limited to geographic locations where there is significant presence of geothermal activity and fluids at shallow depth in the subsurface.
This is a major disadvantage, caused by the fact that while geothermal activity is universal on Earth, the feasibility of geothermal energy extraction by humans is dependent on depth.
All countries cannot use geothermal energy because viable geothermal sites for installation of power plants are not available in all countries.
3). Hazard Risk (as one of the Disadvantages of Geothermal Energy)
Geothermal energy development increases the risk of both anthropogenic and natural hazards
Natural hazards that are associated with geothermal energy development are mainly seismic, such as earthquakes.
Alongside earthquakes, geothermal energy development can cause ecosystem damage, and pose risks to human health [2].
Geothermal fluids often contain brine, and may include traces of nuclear materials, which can increase the risk of skin cancer and other ailments in humans.
Chemicals used in drilling geothermal wells can also be hazardous and increase the risk of pollution [4].
These factors all reduce the appeal of geothermal energy and its sustainability.
4). Low Mobility
After it has been extracted from the subsurface, geothermal energy needs to be transported to the point where it is harnessed, either directly as heat, or to a turbine for electricity generation.
Because it is usually stored in fluids, transport of geothermal energy is very susceptible to problems like energy loss, which make its mobility inefficient.
Although geothermal energy can be used for multiple purposes, its low mobility reduces its prospects as a choice for these purposes under various circumstances. It also further worsens the geographic limitations faced by this type of energy, since geothermal power plants should ideally be located within proximity of the point(s) of end-use.
5). Gaseous Emissions (as one of the Disadvantages of Geothermal Energy)
Geothermal energy is linked to greenhouse emissions that comprise mainly of carbon and water vapor.
When it is being used to generate electricity, steam from geothermal wells can be released alongside other gases like hydrogen, hydrogen sulfide, nitrogen and methane [1] [3].
The main type of pollution that can be caused by geothermal energy utilization is air pollution, while anhydrous gases like CO2 and H2S can contribute to the formation of acid rain.
Although the carbon footprint of geothermal energy is smaller than that of fossil fuels, the fact that it has gaseous emissions implies that it is not absolutely clean and might require additional measures to reduce its environmental impact while it is being used. Such additional measures can increase total cost of utilization.
Conclusion
Disadvantages of geothermal energy are;
1. Capital Cost
2. Geographic Limitation
3. Hazard Risk
4. Low Mobility
5. Gaseous Emissions
References
1). Axtmann, R. C. (1975). "Emission control of gas effluents from geothermal power plants." Environ Lett. 1975;8(2):135-46. Available at: https://doi.org/10.1080/00139307509437427. (Accessed 28 January 2023).
2). Chen, S.; Zhang, Q.; Andrews-Speed, P.; Mclellan, B. (2020). "Quantitative assessment of the environmental risks of geothermal energy: A review." J Environ Manage. 2020 Dec 15;276:111287. Available at: https://doi.org/10.1016/j.jenvman.2020.111287. (Accessed 28 January 2023).
3). Kristmannsdóttir, H.; Sigurgeirssona, M.; Armannssona, H.; Hiartarsonb, H.; Olafssona, M. (2000). "Sulfur gas emissions from geothermal power plants in Iceland." Geothermics 29(4). Available at: https://doi.org/10.1016/S0375-6505(00)00020-1. (Accessed 28 January 2023).
4). Spada, M.; Sutra, E.; Burgherr, P. (2021). "Comparative accident risk assessment with focus on deep geothermal energy systems in the Organization for Economic Co-operation and Development (OECD) countries." Geothermics 95(1–2):102142. Available at: https://doi.org/10.1016/j.geothermics.2021.102142. (Accessed 28 January 2023).
5). Stefánsson, V. (2002). "Investment cost for geothermal power plants." Geothermics 31(2):263-272. Available at: https://doi.org/10.1016/S0375-6505(01)00018-9. (Accessed 28 January 2023).
