Is Geothermal Energy Environmentally Friendly?
Discover why geothermal energy is a sustainable solution for the energy transition. Explore its environmental benefits and its key role in responsible energy development.
The geothermal industry has continuously improved its environmental performance over the decades. A striking example: since 1976, geothermal power plants have reduced their hydrogen sulfide (H₂S) emissions by more than 89%, a gas naturally present in underground reservoirs and recognizable by its rotten egg odor [1]. This spectacular reduction was accomplished while quadrupling geothermal electricity production, demonstrating that it is possible to grow while being more environmentally respectful.
Faced with current climate challenges, identifying renewable and low-emission energy sources has become crucial for a successful energy transition. Geothermal energy positions itself not only as one of the most promising solutions, but also as one of the most environmentally friendly, offering a truly sustainable alternative to traditional fossil fuels.
This article examines in detail why geothermal energy deserves its reputation as clean energy. We will explore its unique environmental benefits, from its remarkable capacity to sequester carbon to its responsible management of natural resources. We will also discover how modern technological innovations have transformed this energy source into a truly sustainable solution for our energy future.
Minimal Environmental Impact of Geothermal Energy
Exceptionally Low Greenhouse Gas Emissions
Geothermal energy produces remarkably low carbon emissions compared to all other energy sources. Geothermal power plants emit 97% fewer sulfur compounds causing acid rain and approximately 99% less carbon dioxide than similarly sized fossil fuel power plants [2]. This exceptional performance positions geothermal energy as a major player in the fight against climate change.
To put these figures in perspective, an average coal-fired power plant in the United States emits approximately 35 times more carbon dioxide (CO₂) per kWh than geothermal power plants [4]. This massive difference means that an average family could reduce its indirect CO₂ emissions by 97% by opting for geothermal electricity rather than that produced by coal.
Revolutionary Carbon Sequestration
The most promising innovation in the geothermal sector concerns the ability of certain facilities to become carbon-negative. The CarbFix project in Iceland perfectly illustrates this revolutionary approach: the Hellisheiði power plant captures approximately 34% of its CO₂ emissions, and more than 95% of the injected CO₂ is transformed into stable carbonates through mineralization in less than two years [3].
This mineralization process consists of injecting captured CO₂ into basaltic formations where it chemically reacts with minerals to form stable carbonates [3]. This transformation guarantees secure carbon storage for millennia, eliminating any risk of future leakage and opening extraordinary prospects for transforming geothermal energy into an atmospheric CO₂ capture technology.
Comparison with Other Renewable Energies
Unlike intermittent energy sources like wind or solar, geothermal energy provides baseload energy available continuously with high capacity factors reaching 82% in 2023 [1]. This consistency avoids the need for energy storage systems or backup power plants running on fossil fuels, further reducing the overall carbon footprint of the energy system.
The land footprint of geothermal energy also surpasses that of other renewable energies. A geothermal power plant uses 404 m² of land per GWh, while a coal-fired power plant uses 3,632 m² per GWh [1], thus preserving natural ecosystems and agricultural lands.
Sustainable Management of Natural Resources
Responsible Water Use
Water management in modern geothermal facilities demonstrates an exemplary level of environmental responsibility. Reinjection is now considered a vital practice in geothermal development because it provides environmentally responsible disposal of wastewater and a sustainable reservoir management tool [5]. This closed-loop practice not only preserves the quality of groundwater but also maintains the pressure of the geothermal reservoir, ensuring sustainable long-term exploitation.
Binary and flash geothermal power plants consume approximately 0.24-4.21 gallons and 1.59-2.84 gallons of water per kWh respectively, compared to 15 gallons of water per kWh used by conventional thermoelectric power plants in 2015 [4]. This remarkable water efficiency positions geothermal energy as an energy solution particularly suited to regions facing water stress.
Geothermal reinjection also has the potential to improve local water quality. So-called "wastewater injection" projects serve the dual purpose of disposing of wastewater, which would otherwise be discharged into local waterways, and rejuvenating geothermal reservoirs with new water sources [5].
Protection of Ecosystems and Biodiversity
Geothermal features in national parks are protected by law [2], ensuring that energy development does not threaten critical ecosystems. This legal protection establishes a delicate balance between energy exploitation and environmental conservation, demonstrating that sustainable development and preservation can coexist harmoniously.
Modern geothermal facilities integrate environmental protection measures from their design. Appropriate management measures can minimize subsidence risks. One of the main environmental challenges associated with geothermal energy is the potential for subsidence due to the withdrawal of hot water and steam from geothermal reservoirs. However, measures can be taken to mitigate subsidence, such as reducing the fluid extraction rate or injecting return water into the reservoirs.
Green Technologies and Environmental Innovations
Cutting-Edge Emissions Abatement Systems
The geothermal industry has developed sophisticated technologies to minimize its already reduced environmental impact. Geothermal power plants use scrubbers to remove hydrogen sulfide naturally present in geothermal reservoirs [2]. Mercury abatement equipment reduces emissions by 90% or more, while H₂S abatement converts more than 99.9% of hydrogen sulfide into elemental sulfur [1].
These remarkable performances transform potentially problematic emissions into valuable byproducts. The recovered elemental sulfur finds commercial applications in the chemical and pharmaceutical industries [1], perfectly illustrating the principles of the circular economy.
Quebec's Geothermal Potential: An Environmental Opportunity
A Largely Untapped Potential
The United States has exploited less than 0.7% of its geothermal potential [4], and Canada presents a similar situation despite its considerable resources. This massive underutilization represents an extraordinary opportunity for Quebec to develop a clean and local energy source, reducing its dependence on imported fossil fuels.
Enhanced geothermal systems (EGS) exponentially multiply this potential by enabling the exploitation of geothermal resources in traditionally less geologically favorable areas [4]. This technology could revolutionize access to geothermal energy in Quebec, transforming the province into a pioneer of geothermal energy in Canada.
Positive Environmental Impact for Quebec
Geothermal development in Quebec could contribute significantly to provincial climate objectives. Each year, American geothermal energy offsets the emission of 22 million tons of CO₂, 200,000 tons of nitrogen oxides, and 110,000 tons of particulates from coal-fired power plants [4]. Proportional development in Quebec would generate substantial environmental benefits for the province.
The integration of geothermal energy into Quebec's energy mix, already largely decarbonized thanks to hydroelectricity, would allow energy diversification while maintaining environmental excellence. This complementarity between hydroelectricity and geothermal energy would position Quebec as a global leader in clean energy.
Geothermal Energy: A Pillar of Our Energy Future
Geothermal energy proves to be a truly exceptional energy source from an environmental standpoint, even surpassing other renewable energies in several key areas. Its negligible emissions, its unique carbon sequestration capacity, its responsible management of natural resources, and its remarkable energy efficiency make it an essential pillar of the sustainable energy transition.
Continuous technological innovations, from perfected emissions abatement to revolutionary CO₂ sequestration, position geothermal energy not only as an alternative to fossil fuels, but as a technology capable of actively contributing to the reduction of atmospheric CO₂.
For Quebec, the development of this clean and local resource represents a unique opportunity to strengthen its environmental leadership while diversifying its energy portfolio. By exploiting its considerable geothermal potential, the province could demonstrate that economic excellence and environmental responsibility can perfectly converge toward a truly sustainable energy future.
References
[1] Geonardo. "Environmental Impacts of Geothermal Energy." 2020. Geonardo, 2020, https://geocom.geonardo.com/assets/elearning/8.1.GE%20vs%20Environment.pdf.
[2] U.S. Energy Information Administration (EIA). "Geothermal Energy and the Environment." 2022, https://www.eia.gov/energyexplained/geothermal/geothermal-energy-and-the-environment.php.
[3] BKV Energy. "Environmental Impact of Geothermal Energy." 2025. BKV Energy, https://bkvenergy.com/learning-center/environmental-impact-of-geothermal-energy/.
[4] Center for Sustainable Systems, University of Michigan. "Geothermal Energy Factsheet." 2022, https://css.umich.edu/publications/factsheets/energy/geothermal-energy-factsheet.
[5] Kamila, Z., et al. "Reinjection in geothermal fields: An updated worldwide review 2020." Geothermics, vol. 89, 2021, https://www.sciencedirect.com/science/article/abs/pii/S0375650520302625.