What is Geothermal Energy?

Clean, Sustainable Energy for the benefit of Humanity and the Environment

Geothermal energy - heat from the earth - is an important energy source having environmental and economic advantages over fossil and nuclear energy sources. Electricity generated from geothermal steam supplies power without polluting our atmosphere or water, or creating radioactive waste. Clean heat from geothermal water dries vegetables, heats greenhouses, and warms clusters of homes and buildings in district heating systems. Geothermal heat pumps provide highly efficient heating, cooling, and hot water for homes and schools.

Only a small fraction of our available geothermal resources are being used today. Improvements in technology and widening recognition of geothermal energy's true value will lead to a greatly increased amount of this clean, reliable resource being developed in essentially all countries of the world. Geothermal energy is a vital part of a sustainable future.

Types of Geothermal Systems

Hydrothermal System:

Geothermal aquifers exploit heat from the earth’s crust through naturally occurring ground waters in deep porous rocks. The exploitation of these aquifers as a source of energy requires a production borehole to extract the water and an injection hole to dispose of the cooled water. An alternative single hole configuration can be used where, instead of using an injection well the used water is simply discharged to the sea or some other convenient sink. Because of the poor thermal conductivity of rock and low-fluid recharge rates, heat is usually extracted at a greater rate than it is replenished from the surrounding rock mass. Geothermal aquifers are, therefore, not ‘renewable’ resources in the strict sense of the word, but are usually grouped along with renewable.

Enhanced Geothermal System:

Enhanced Geothermal System (EGS or Engineered Geothermal System (EGS) or Hot Dry Rock (HDR), or Hot Fractured Rock (HFR) are different acronyms used for technology developed to extract earth natural heat by artificial injection of cold water into crystalline plutonic rocks or metamorphic ‘basement’ complexes. Water is pumped down one well to induce hydraulic fracturing to create a reservoir. Water is then circulated under pressure through these fractures, absorbing heat before returning to the surface via one or more production wells.

This system derives its names from the fact that a Hydrothermal reservoir is artificially created. The power generation threshold from these systems has the ability to exceed the total present and future energy demands.