In binary plants, the hot water is passed by a secondary fluid with a much lower boiling point than water. The steam that results from this process is used to drive the turbine. Flash plants pull deep, high-pressure hot water into cooler, low-pressure water. Dry steam, the oldest geothermal technology, takes steam out of fractures in the ground and uses it to directly drive a turbine.

There are three types of geothermal power plants: dry steam, flash, and binary. The first geothermally generated electricity was produced in Larderello, Italy, in 1904. To produce geothermal-generated electricity, wells, sometimes a mile (1.6 kilometers) deep or more, are drilled into underground reservoirs to tap steam and very hot water that drive turbines linked to electricity generators. cities pipe geothermal hot water under roads and sidewalks to melt snow.Įnergy 101: Geothermal Heat Pumps Production of Geothermal Energy Geothermal water from deeper in the Earth can be used directly for heating homes and offices, or for growing plants in greenhouses. These underground reservoirs of steam and hot water can be tapped to generate electricity or to heat and cool buildings directly.Ī geothermal heat pump system can take advantage of the constant temperature of the upper ten feet (three meters) of the Earth’s surface to heat a home in the winter, while extracting heat from the building and transferring it back to the relatively cooler ground in the summer.

It can be found from shallow ground to several miles below the surface, and even farther down to the extremely hot molten rock called magma. This thermal energy is contained in the rock and fluids beneath Earth’s crust. It is simply power derived from the Earth’s internal heat. Geothermal energy has been used for thousands of years in some countries for cooking and heating.

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