Besides the Sun, the Earth's interior provides heat energy that can be effectively used for generating electricity. Yes, geothermal energy has been in existence since hundreds of years; however, extensive research has led to the possibility of tapping this renewable source of energy. The word geothermal is derived from two words, "geo" and "thermal." Geo stands for "Earth" and thermal is related to heat energy. So, it is the energy that is generated inside the layers of the Earth's surface.
One of the most interesting facts about this energy source is that it is generated deep within the Earth's surface. The Earth has three layers: the crust, the mantle, and the inner core. Crust is the outermost part of the Earth's surface, and it is this part that forms the continents and ocean floors. The thickness of this layer is usually between 3 and 5 miles under the oceans and between 15 and 35 miles on the continents. The mantle or the middle part surrounds the core and is nearly 1800 miles in thickness. Magma and rocks are the major constituents of this layer. The innermost layer or the inner core is divided into two cores, one is called the solid iron core and the other, hot melted rock or magma.
The Earth's crust is broken into a large number of pieces called plates. The hot melted rock or magma comes close to the edges of these plates and forms the volcanoes. The lava that comes out from a volcano is nothing but the magma. The deepest part of inner core contains magma at temperatures higher than the Sun's surface. The rocks and water found in the deep underground parts of the Earth's surface absorb heat from the magma. The temperature increases with an increase in the depth of the Earth's surface.
Where it is Found
Geothermal energy is hidden in the depths of the Earth's surface; however, it often finds its way out to the surface in the form of volcanoes, geysers, and hot water springs. Generally, its major sources are the areas close to the major plate boundaries of volcanoes and earthquakes. The area called a "ring of fire," encircling the gigantic Pacific ocean, is a very popular region for a lot of geothermal geysers and water springs. In the United States, geothermal reservoirs are found in the western states of Hawaii, Utah, Nevada, etc. California holds the distinction for producing most electricity from this energy. The US government has strict laws regarding the misuse of the lands in the Yellowstone National Park, where geysers and similar features are found.
Some more interesting facts about this energy source are as follows:
- Geologists test the presence of a geothermal reservoir by drilling a well and recording the temperature deep beneath that place.
- The entire resource of geothermal energy has been found to be more than that of coal, gas, and uranium combined.
- Philippines produce 27% of the nation's electricity consumption by this energy source. It is the world leader in its production.
- Sites where this energy is tapped are called geothermal springs and in these places, water seeps into the Earth's surface and resurfaces as hot water; the planet's interior heats it up.
- No fuel is consumed in producing geothermal electricity and the heating and cooling systems, so it is absolutely emission free.
- The US government provides "geothermal tax credit" that is a form of incentives to people saving electricity by installing such heating and cooling systems.
- Geothermal plants emit 97% less acid content than fossil fuel plants.
Geothermal energy is considered to be a viable option for generating electricity, cooling and heating homes, and is used in almost 20 countries of the world. Except for the high initial cost and space for installation, it is an excellent alternative energy source.