l'energie de la terre

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Frequently Asked Questions



What are the different types of geothermal energy?
>> Very low-temperature geothermal energy
  • Shallow aquifer
  • Temperature lower than 30°C
  • Used for heating or air conditioning by way of a heat pump

>> Low-temperature geothermal energy (low temperature, low enthalpy)

  • Extracting water at less than 90°C
  • Reservoirs between 1500 and 2000 meters
  • Used for heating and some industrial applications

 >> Medium-temperature geothermal energy (average temperature or enthalpy)

  • Hot water or wet steam between 90 and 150°C
  • Geothermally favorable zones at a depth of less than 1000 meters and in sedimentary basins from 2000 to 4000 meters
  • Used for some industrial applications and electricity production using a binary fluid cycle
>> Geothermal high energy (high temperature or enthalpy)
  • Fluids hotter than 150°C
  • Reservoirs between 1500 and 3000 meters below the surface in high-gradient zones
  • Fluids are recovered in the form of wet or dry steam

How would you describe sustainable development in just a few words ?

>> The history of sustainable development, step by step
1971 : A meeting of economists from the northern and southern hemispheres (Founex, Switzerland).The first discussions of a way to link the economy, resources and the environment while taking into consideration the social factors.
1972 : “The Limits of Growth” report (the Club of Rome). The beginning of an understanding of the limits of natural resources, especially the fossil fuels which powered post-war economic development.
June 1972 : A United Nations conference about the environment in Stockholm. In the wake of the first large-scale industrial disasters on an international scale, the first global conference was the first time environmental issues entered into mainstream politics.
1987 : “Our Common Future” report (Brundtland Commission, UN). This laid out the concept of “Sustainable Development”. The paper gains popularity; it is translated into several foreign languages.
June 1992 : A UN conference on the environment and development in Rio de Janeiro
2002 : Johannesburg: A UN conference on the environment and development
2012 : The Earth Summit, July 2012, known as “Rio+20”
>> Tools :
Development is sustainable when it guarantees economic efficiency, social justice and ecological viability, following these principles:
  • Solidarity in time and space
  • Cross-sector approach
  • Participation
  • Precaution
  • Subsidiarity
  • Responsibility
>> Values
  • Respect
  • Empathy towards living things
  • Reciprocity
  • Responsibility
  • Foresight
  • Knowledge of our limits
  • Creativity and knowledge
  • Humility, or wisdom