What is geothermal energy?

The term “geothermal” means “Earth heat” or “heat of the Earth.”. The heat flowing from the Earth’s interior is estimated to be equivalent to 44.2 terawatts-thermal (TWth) of power (Pollack et al.1993). This is more than twice the amount needed to supply total global primary energy consumption in 2015 (Energy Information Administration [EIA] 2017a). So, why isn’t this renewable energy source more widely deployed?

Clean sustainable energy source.

In times of climate change this type of sustainable energy source is vital for all humankind. It is known to be robust, economic and the most reliable energy source, which can provide baseload power to the grid, complementing the unsteadiness of solar and wind.  Further in a droughts situation and when hydro is not available, then geothermal is available and stable. To reach this energy you require drilling deep wells into the earth.  The most common depth of a geothermal well is from 2000-3000 meters. Heat pumps using low temperature near the surface are not the subject in this short description.

The amount of usable energy from geothermal sources varies between locations, with depth and by extraction method.  The most common extraction approach is when the hydrothermal fluid or steam are brought to the surface.  The hot water or steam then powers a turbine that generates electricity.  There are mainly three types of geothermal power plants.  Those are, dry steam plants, flash steam plants and binary cycle power plants. Flash system is the most widely selected configuration for high temperature resources.

The geothermal energy is not only used to produce electricity.  It can be used directly as heat (direct use), such as space heating and bathing, and even for air conditioning in summertime or in warmer countries. There is enormous potential to use geothermal heat directly. Agriculture and industries can benefit too. The cascaded use of the energy can for example provide heat for food dehydration (drying), heat for greenhouses, and milk pasturing just to mention few out of many options.

If you like to watch a video explaining geothermal click here

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