Geothermal Energy: Harnessing the Earth’s Heat for Sustainability

Geothermal energy captures the heat stored beneath the Earth’s surface to produce electricity or provide heating. This is made possible through geothermal reservoirs, underground areas where heat accumulates in rocks and fluids.

Geothermal plants are specifically designed to capture and transform this energy. In large-scale power plants, engineers drill up to 3,000 meters deep in areas with abundant geothermal resources. There, heat appears as steam or high-pressure hot water, which rises through wells and drives turbines to generate electricity.

Beyond electricity production, geothermal energy is widely used for direct heating. Whether from high- or low-enthalpy resources, heat can be distributed through thermal exchange systems connected to district heating networks. This makes it possible to ensure efficient, constant heating year-round with minimal environmental impact.

The environmental and economic benefits of geothermal energy

Geothermal energy provides major advantages both for the planet and the economy. It is a renewable, clean, and always available resource, regardless of weather conditions. This makes it invaluable for decarbonization and energy security.

From an environmental perspective, geothermal power stands out for its low CO₂ emissions and minimal impact on the landscape. Unlike fossil fuels, geothermal systems do not involve combustion and release no harmful emissions. Many operate in closed-loop circuits, where thermal fluids are re-injected underground, preventing contamination and preserving resources.

Economically, geothermal systems are a smart long-term investment. While installation costs may vary depending on depth and plant size, operational costs are very low. For example, geothermal heat pumps consume electricity to function, but they generate far more thermal energy than they use, dramatically lowering utility bills.

Geothermal systems also require minimal maintenance, can last decades (over 25 years for heat pumps and up to 50 years for geothermal probes), and even increase property value thanks to their energy efficiency.

Another key advantage: geothermal is stable and reliable, unlike solar and wind energy, which depend on weather conditions.

Low- and high-enthalpy geothermal energy: the differences

Low-enthalpy geothermal energy is ideal for residential use, relying on temperatures below 90°C. Domestic systems use shallow probes combined with a geothermal heat pump to heat or cool buildings.

High-enthalpy geothermal energy is used in power plants to generate electricity. It requires deeper drilling, where temperatures exceed 150°C.

Both solutions are sustainable, but they serve different applications: low-enthalpy for residential and local needs, high-enthalpy for industrial and large-scale power generation.

The role of geothermal energy in the energy transition

Geothermal energy plays a strategic role in the ecological transition toward a sustainable energy system. Thanks to its continuous availability and low environmental footprint, it complements other renewables such as solar and wind.

By investing in geothermal plants—whether domestic or industrial—we can decarbonize energy consumption, improve building efficiency, and support climate neutrality goals.

In the long run, geothermal energy represents a concrete, reliable, and sustainable choice for reducing environmental impact and ensuring clean and secure energy for all.

Renewable sources: https://www.italgas.it/en/what-we-do/gas/renewable-gas/

Energy efficiency: https://www.italgas.it/en/what-we-do/energy-efficiency/

Ecological transition : https://www.italgas.it/en/about-us/italgas-for-transition/