How Geothermal Energy Is Found

A number of energy types are used for residential and commercial purposes these days. Some are increasingly becoming popular because of their green attributes. One of these green energy types is geothermal energy.

What is Geothermal Energy?

Geothermal energy refers to the heat energy that naturally occurs in the Earth’s subsurface.  This heat is contained in rocks and undergoround fluids. In some parts of the world, it can be tapped as a store of energy.

Exploring for and Developing Geothermal Resources

The search for usable geothermal energy is referred to as geothermal exploration. A number of techniques are used including field and office analysis, geotechnical drilling, and geochemical evaluation.

Geochemical techniques are widely utilized. Elemental and isotopic analyses are often made. Geothermometers and other technologically advanced instruments measure the subsurface temperatures and other attributes of the subsurface.

Magnetic techniques are also widely used. Some components of the subsurface are more magnetic than others. Identification of the Curie Point, the temperature at which certain magnetic minerals such as magnetite undergo a sharp change in their magnetic properties, helps geologists make accurate models of the subsurface.  

Most heat in the subsurface is transported naturally by the movement of hot or warm fluids. Subsurface fluid flows are often zones of low electrical resistance. Therefore, electrical resistivity and conductivity studies are also important in the assessment of geothermal resource potential.

Gravity studies are also very important in the exploration for geothermal energy. In fact, gravity surveys are often one of the first methods used, because they can identify large subsurface anomalies that may be conducive to geothermal development. Many of these gravity surveys are conducted by aircraft, including drones.

Finally, many geothermal areas are associated with significant naturally-occurring seismic activity. Understanding the general nature of this seismicity, particularly how strong these earthquakes might be, are important when developing the infrastructure associated with geothermal installations.