It is widely known that the energy transition from conventional energy sources to renewable sources represents a critical challenge that governments must address, while consumers themselves must also become more aware of their personal environmental footprint. Undoubtedly, a key ally in achieving the “shift” from the use of fossil fuels to cleaner and more sustainable energy alternatives is citizen awareness. For this reason, this article explores the relationship between the environmental impacts and the costs of utilizing geothermal energy compared to natural gas, given that both energy sources can be used for residential heating, cooling, and hot water production.
To delve deeper, it is first important to discuss the environmental impacts resulting from the extraction and processing of natural gas up to its consumption in a broader context. Specifically, during the drilling process to recover available natural gas reserves, high energy consumption is required, and toxic gases are released, while phenomena such as soil erosion and excessive noise are observed. Furthermore, groundwater contamination due to possible leaks from the reservoir and the occurrence of minor seismic tremors are common problems associated with the use of hydraulic fracturing to extract natural gas. Additionally, the construction of complex infrastructures for the processing and transportation of recovered reserves is accompanied by the fragmentation of local ecosystems and the potential for unpredictable incidents such as ignition and leaks, which can contribute to environmental disasters. It is worth noting that the liquefaction of one ton of natural gas releases 0.4 tons of carbon dioxide. Although power plants generate 50%-60% fewer pollutant emissions compared to other fossil fuels, the combustion of natural gas remains a significant factor in air quality degradation and contributes to the greenhouse effect.
On the other hand, regarding the utilization of geothermal energy, the production of materials required for the construction of geothermal installations and piping, as well as the use of heavy
machinery for drilling geothermal wells, is associated with moderate energy consumption and the release of air pollutants compared to similar projects in the exploitation of natural gas. For example, in the process of production, transport, and installation of geothermal heat exchangers for a low-enthalpy geothermal well, an average of 160 kilograms of carbon dioxide is emitted. In contrast, for the production, transport, and construction of a natural gas distribution pipeline of the same size as the geothermal project described above, an average of 16 tons of carbon dioxide is emitted.
It is also important to refer to the life cycle of each energy source. Geothermal energy is a renewable and practically inexhaustible energy source, ensuring the long-term sustainability of the systems that utilize it. In contrast, dependence on natural gas as a finite fossil fuel inevitably leads to its depletion, rendering associated facilities inactive and requiring their full replacement with other energy sources.
Regarding the investment in a geothermal project to meet the energy needs of a household, it is essential to compare the two energy sources from an economic perspective. Clarifying, although the installation of a geothermal system is associated with a significantly higher initial construction cost compared to a natural gas system, the operating costs are much lower, resulting in an estimated payback period ranging from 5 to 7 years. Additionally, the low maintenance needs extend the lifespan of a geothermal pump (20-25 years), which is significantly longer than that of a natural gas boiler (10-15 years).
In summary, after comparing the two energy sources mentioned above, it becomes clear that the utilization of geothermal energy, although characterized by a high initial construction cost, significantly reduces during the operation phase, and the overall environmental footprint is almost negligible, in contrast to the use of natural gas, which entails a high footprint from extraction to combustion, without the possibility of payback. Furthermore, considering that global natural gas reserves are estimated to last for about 50 more years, it becomes evident that geothermal energy is the superior long-term solution for achieving a greener future.