Geothermal Power As Renewable Energy
The Earth itself can be thought of as a giant battery. All the solar radiation that is absorbed by the planet as short wave solar energy is then radiated back out to space every night as long wave radiation. In most areas, the sub soil is kept at a constant 50F/10C, no matter the time of year.
Geothermal Renewable Energy
In a few hot spots, the Earth’s crust is very thin with fingers of magma that lies close to the surface. This causes the ground to be much, much warmer – enough to reliably generate steam that can be put to work.
The most commonly used geothermal device is the heat pump. This snakes a long pipe, filled with water or anti-freeze through the earth or plunged into a lake or pond. The fluid is then circulated under the floor of a building or into a heat exchange unit where a current is created with any excess energy.
Geothermal As Passive Renewable Energy
A very small number of heat pumps are used for heating only, but the vast majorities are passive units used for both heating and cooling assistance. Most often the heat pump is used to lower heating costs in the winter by taking the “chill off” so only about 20F of heat needs to be generated.
Iceland, the Philippines, Mexico and Italy all have large active geothermal facilities, with smaller ones in several other countries and many more in the planning stages. However, this only supplies about 1% of the world’s energy needs for now.
Geothermal For Large Scale Renewable Energy
Ideally these are found in areas where there is also submerged groundwater. Therefore, steam plant operations also use a very great amount of freshwater. Some still-hot fissures that have run out of water have been able to be recharged with sea water or even municipal sewage, as is done in California.
Large scale geothermal renewable energy installations have been on line for many years, but are limited to areas where there are already deep, heated fissures. The Geysers geothermal installation in California has produced a steady 750MW supply – enough to power over 56,000 typical homes, by some estimates.
