Topic – Geothermal Electricity

Geothermal Energy

Creating Electricity

Most of the electricity people use is generated at places called power plants. Electricity is created when magnets spin inside a generator at the power plant. The magnets spin because they are connected to a turbine that spins. It takes energy to make the turbine spin.

There are different ways to make a turbine spin. Some power plants use the energy of moving water to make a turbine spin. Steam can also make a turbine spin. In a coal power plant, heat from burning coal is used to turn water into steam. Some power plants burn oil to turn water to steam. Burning coal or oil puts pollution into the air.

Geothermal Power Plants

In some places, there are power plants that use water from a reservoir, or pool, that is deep underground. This water is already very hot, so there is no need to heat the water to create steam. These power plants are called geothermal power plants. (See the diagram below.)

Geo means “from the Earth” and thermal means “heat.” A geothermal power plant uses water that is heated by Earth. How does this happen? Deep inside Earth, the temperature is hot enough to melt rock. We see this melted rock when a volcano erupts. The lava that comes out of a volcano is molten, or melted, rock.

Water that is deep underground is heated by Earth. At a geothermal power plant, pipes pump hot water from 2 or 3 km underground. At the surface of Earth, the hot water turns to steam. The steam makes a turbine spin. The spinning turbine makes magnets in the generator spin. The spinning magnets generate electricity.

Once the steam has passed by the turbine, the steam goes to a cooling tower. As the steam cools, it condenses back into water. Then the water travels through a pipe that takes it back underground. The Earth heats the water again, so the geothermal power plant can use the same water over and over again.

How a Geothermal Power Plant Works

1. Hot water is pumped from a reservoir deep underground.

2. The hot water turns to steam.

3. Steam makes the turbine spin. The turbine makes magnets spin inside the generator. Electricity is created.

4. Steam condenses into water at the cooling tower.

5. The water goes back underground, where it is heated again.

Benefits of Geothermal Power Plants

Most people who are worried about the environment think geothermal power plants are a good idea. One reason is that geothermal power plants do not pollute the air by burning coal or oil to change water to steam. Another reason is that the hot underground water that geothermal power plants use is a renewable resource. The water goes back underground, so it is not used up. Coal and oil are not renewable resources.

Fun Facts

•  In Iceland, 25% of the country’s total electricity is generated by geothermal power.

•  In Canada, there are currently 6 geothermal power projects underway in Alberta, Saskatchewan, British Columbia, and the Northwest Territories.

•  In 1904, Italy became the first country to use geothermal power to create electricity.

•  Farmers in Italy have used geothermal energy for hundreds of years to heat water for winter crops.

•  In the western United States, including Hawaii, geothermal energy sources are closer to Earth’s surface. There are many geothermal power plants on the west coast of the United States.

•  Although geothermal energy is a very clean energy source, there are some solid waste products left over. Zinc and sulphur are waste minerals left from the process that need to be disposed of or sold.

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