Geothermal power plants use steam to produce electricity. The steam comes from reservoirs of hot water found a few miles or more below the earth’s surface. The steam rotates a turbine that activates a generator, which produces electricity.

Hot water near the earth’s surface is piped into buildings for heat. A district heating system provides heat for most of the buildings in Reykjavik, Iceland. Industrial applications of geothermal energy include food dehydration (drying), gold mining, and milk pasteurizing.

There are four types of geothermal power plants: dry steam, flash steam, binary cycle, and enhanced geothermal systems (EGS). All four types of geothermal power plants produce electricity by using underground steam or hot water to turn generator turbines.

Geothermal heat pumps don’t generate heat — they just transfer it from the ground into your home. For every 1 unit of energy used to power your geothermal system, on average 4 units of heat energy are supplied. Why geothermal heat pumps use more electricity than furnaces (but less than conventional air conditioners)

What are the Disadvantages of Geothermal Energy?

• Environmental Concerns about Greenhouse Emissions.
• Possibility of Depletion of Geothermal Sources.
• High Investment Costs for Geothermal System.
• Land Requirements for Geothermal System to Be Installed.

On an average, a homeowner can expect to invest about $12,000 to $30,000 as geothermal heating and cooling cost. This cost would cover a complete geothermal installation. For large homes, the cost can range from $30,000 to $45,000 for high end ground source heat pump systems.

Geothermal HVAC systems are not considered a renewable technology because they use electricity. Fact: Geothermal HVAC systems use only one unit of electricity to move up to five units of cooling or heating from the earth to a building.