What is Geothermal Energy?
Geothermal energy is thermal energy (heat) that is generated and stored within the Earth's crust. The term 'geothermal' originates from the Greek words 'geo,' meaning earth, and 'therme,' meaning heat. This heat is a result of the planet's formation and the radioactive decay of minerals in the Earth's core.
Section 2: How Geothermal Energy is Harnessed
This energy is harnessed by drilling wells deep into underground reservoirs to access steam and hot water. This steam or hot water can then be used directly for heating applications or, more commonly, to drive turbines connected to electricity generators. The method used depends on the temperature and pressure of the resource.
Section 3: A Practical Example
A common example is a flash steam power plant. These plants pump high-pressure hot water from deep underground into a lower-pressure tank at the surface. This sudden pressure change causes the water to rapidly 'flash' into steam, which then spins a turbine to generate electricity. Iceland famously derives a significant portion of its electricity and heating from such geothermal sources.
Section 4: Importance and Applications
Geothermal energy is important because it is a reliable, renewable, and clean energy source. Unlike solar and wind power, it is available 24 hours a day, 365 days a year. It has a small physical footprint on land and produces significantly lower greenhouse gas emissions than fossil fuels, making it a key tool in combating climate change.