WHAT DOES THE WORD “GEOTHERMAL” MEAN?
“Geothermal” comes from the Greek words geo (earth) and therme (heat). So, geothermal means earth heat.
WHAT IS GEOTHERMAL ENERGY?
Our earth’s interior – like the sun – provides heat energy from nature. This heat – geothermal energy – yields warmth and power that we can use without polluting the environment.
Geothermal heat originates from Earth’s fiery consolidation of dust and gas over 4 billion years ago. At earth’s core – 4,000 miles deep – temperatures may reach over 9,000 degrees F.
HOW DOES GEOTHERMAL HEAT GET UP TO EARTH’S SURFACE?
The heat from the earth’s core continuously flows outward. It transfers (conducts) to the surrounding layer of rock, the mantle. When temperatures and pressures become high enough, some mantle rock melts, becoming magma. Then, because it is lighter (less dense) than the surrounding rock, the magma rises (convects), moving slowly up toward the earth’s crust, carrying the heat from below.
Sometimes the hot magma reaches all the way to the surface, where we know it as lava. But most often the magma remains below earth’s crust, heating nearby rock and water (rainwater that has seeped deep into the earth) – sometimes as hot as 700 degrees F. Some of this hot geothermal water travels back up through faults and cracks and reaches the earth’s surface as hot springs or geysers, but most of it stays deep underground, trapped in cracks and porous rock. This natural collection of hot water is called a geothermal reservoir.
A great extend of details available from Geothermal Education Office website about how the geothermal energy has been used in the past and which countries using this clean energy at the present and how we can explore the geothermal energy in the future can be found here at Geothermal Energy Facts