Geothermal energy: power from the depths of the earth

By ENGIE - 13 July 2022 - 14:45

A local, sustainable resource, geothermal energy produces heat, refrigeration, and electricity. Here are five things to deepen your knowledge about geothermal energy, a precious resource from the depths of the earth.


1. Heat production, refrigeration, and electricity: geothermal energy does it all!

Indeed, geothermal energy is not limited to heating buildings! It harnesses the energy that is found in the ground to provide heat… and cold, too. In the summer, underground coolness can help lower building temperatures more virtuously than traditional air conditioning systems, which tend to be energy intensive. Ground heat can also be transformed into electricity, as is the case in Iceland, Italy, and French overseas departments and regions. The goal? High-temperature water is collected from great depths and transformed into steam as it rises to the surface. The steam is then used to turn a turbine to power an alternator that produces alternating current. Geologically, 100% of the French territory lends itself to at least one type of geothermal technology which could be used for multiple purposes. 

>> More on the uses and advantages of geothermal energy <<


2. Geothermal energy is super ecological!

By nature, geothermal resources are available 24/7, independently of weather and seasonal conditions. They are capable of directly providing renewable coolness or heat, without releasing heat back into the atmosphere, and can even provide thermal energy storage throughout the year. Locally sourced, transport and carbon-free, inexhaustible energy! For example, it is being used at the ENGIE campus, the Group’s future headquarters


3. Geothermal energy, a locally sourced energy

This energy is especially interesting when used locally: establishing plants near natural water reservoirs helps avoid long-distance transport and in so doing, better conserve and use its heat. Geothermal energy is available everywhere in different forms, by drilling from several metres to two kilometres deep. Similarly, while the depth and multitude of geothermal drilling have an impact on the initial investment, this renewable has the lowest long-term cost, since facilities have low maintenance costs. 

>> Find out about a city supplied with geothermal energy <<


4. Innovation that serves geothermal energy

Geothermal energy is a continually changing energy. More and more innovations are being explored, much like multi-drain geothermal drilling technology which is being developed in Europe for the first time by ENGIE. It makes it possible to penetrate a geothermal reservoir several times and give plants the greatest energy production capacity. Branded as Solar Impulse, the innovation received the 2021 Ruggero Bertani European Geothermal Innovation Award, from the European Geothermal Energy Council (EGEC).


5. Geothermal energy is also found in our oceans 

Hot water on the surface and cold water from sea beds are delivered to an onshore plant to produce heat or coolness. This is the case of the Thassalia project, developed in Marseille. This innovative plant is the first in France and in Europe to use ocean thermal energy to heat and cool buildings. Going forward, 500,000 m² will be connected to it!


>> Find out more about geothermal energy <<