Geothermal energy/power uses the heat that is generated and stored in the earth’s crust. It taps into underground reservoirs of steam and hot water, and harnesses that heat to generate electricity. Since this renewable energy source requires drilling underground wells up to a mile deep, it leaves a very small ecological footprint but, this energy is naturally replenished by the earth so will not deplete in the long term.
The three types of geothermal power plants are dry steam, flash steam plants, and binary cycle. An open loop system pumps water from a well, pond, or lake and returns it to surface water. An electric heat pump is used to concentrate the energy in the fluid from the earth and is then used to heat or cool a building.
A closed loop system uses a grid of pipes to pump heat fluid. This process can produce 3-4.5kW of heat for every kW of electricity used and consumes 50-70 percent less electricity than conventional heating systems.
A geothermal heat pump is a two-in-one HVAC system that can be used for both heating and cooling. Geothermal heating works by moving the fluid in an underground loop of pipes and collecting the thermal energy deposited. For the cooling system or AC, as air circulates inside the area, the heat pump removes heat from the air and transfers it to the fluid that is circulating underground. This system can reduce electricity use by 25 to 50 percent and though they have large upfront costs, they are much more affordable than conventional AC units.
The installation of a geothermal system can average $25,000 to $35,000. This cost should pay back in 5 to 10 years and results in energy cost savings of 40 to 60 percent. This system typically lasts 20 to 25 years if maintained for leaks, water contamination, and corrosion.
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