WHY GEOTHERMAL?
The Value of Energy Below Your Feet
THE BASICS
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FROM DEEP WITHIN
In the center of the earth, large amounts of heat energy are generated from the radioactive decay, which then conducts from the earth’s core through several layers of rock and magma. This energy heats reservoirs of hot water in the Earth’s crust and is stored at varying depths depending on the geographical location. For example, these reservoirs are very difficult to reach in the midwest while Yellowstone National Park has hot geysers at the surface.
AT THE SURFACE
Another useful property of the Earth is that the ground maintains a constant year-round temperature below the surface, due to the radiation of the sun. The ground acts as a “thermal battery”. Below the frost line a few feet beneath the surface, the ground is at a steady temperature of 55 degrees Fahrenheit which provides an opportunity for heat exchange using a heat pump. During hot seasons, the heat from the hot air is transferred to the liquid that goes underground to a geothermal “field” (a collection of tubes filled with water or refrigerant). The field then cools the liquid in the tubes by transferring the heat from the tubes into the earth, and the fluid leaves the field at a cooler temperature. During cold seasons, the process is reversed and heat from the Earth is transferred into the liquid in the field and the liquid leaves at a hotter temperature.
THE BENEFITS
Not too good to be true
CLEAN ENERGY
These processes harness available heat that is constantly being generated from the Earth’s core or stored in the crust, which makes it a renewable resource.
EFFICIENCIES
Geothermal heat pumps are very efficient since the ground helps out with the heating and cooling for free. Compared to normal HVAC units, geothermal heat pumps can decrease energy costs by 30-70% for heating and 20-50% for cooling. On cold winter nights, the heat pumps can operate at efficiencies of 300%-600%.
PRO USA
Heat pumps can be installed anywhere in the U.S., and electricity generation and direct use can be applied in the Western U.S. Increasing geothermal technologies creates U.S. jobs as most of the equipment is made domestically. It will also increase energy stability since the systems can operate 24 hours a day, and improve U.S. energy independence.
THE EXAMPLES
ELECTRICITY AND DIRECT USE
These deep reservoirs can be accessed by drilling, and these high-temperature resources can be used to create steam for turbines and generate electricity. In the U.S., these plants only exist in the Western states. When it is not economical to use the resources for electricity, they can instead be used for direct heating in applications such as district heating, aquaculture, agricultural or industrial processes.
