There are many types of power sources. The most popular power source is fossil fuels (coal, oil, gas). Fossil fuels were formed when ancient plants and animals died hundreds of millions of years ago. As their bodies decayed, they were mixed with the sand and mud and buried deep in the earth. Compression and heat over thousands and thousands of years changed them into fossil fuels.
Although fossil fuel is the most common power source, it is not the only one. Here are some other power sources that we use today:
|Oil and Gas are used to produce electrical energy, mechanical energy, and heat energy. Oil and gas are pumped from wells deep in the ground and under the ocean. They are then sent through pipelines to be refined or cleaned. A sedimentary rock called shale may also contain oil. When oil-containing shale is heated at high temperatures oil can be extracted.|
|Wood and Coal are used to produce mechanical, electrical, and heat energy. Coal is mined underground near the earth's surface. It is burned in its natural form to produce heat. Coal can also be converted to a liquid or gas form. Hydrogen is added to a heated and pressurized mix of coal to produce an oil-like liquid or gaseous product.|
|Nuclear Power is used to make electricity. Inside a reactor atoms from a fuel called uranium are split by neutrons (nuclear fission). This energy is released as heat which changes water into steam that runs turbine generators.|
While these power sources are used to produce most of the earth's electricity, it is important to remember that some of them are non-renewable, which means that they can not be naturally restored in a short period if time. We always run the risk of exhausting our supply of non-renewable power resources.
Renewable Power Sources
Renewable energy is a source of energy that can never be exhausted. We can obtain renewable energy from the sun (solar energy), from the water (hydropower), from the wind (windmills), hot water springs (geothermal) and even from firewood, animal manure, crop residues and waste (Biomass).
|Solar Power is renewable because it is provided by the light of the sun. The best things about solar electricity are that it is free, ever lasting, and non-polluting. When the sun shines on solar cells they absorb its energy, causing a chemical reaction that generates electricity - just like in a solar powered calculator. More complicated solar systems can be used to provide electricity to pump water, power communications equipment, and even provide electricity to our homes.|
|Water Power (hydropower) can produce mechanical and electrical energy. Dams are used to contain flowing river water forming lakes and reservoirs. As water flows downhill it is channelled to a turbine or water wheel. The force of the flowing water turns the turbine or wheel, which turns a generator to make the electricity. Water power has been used for hundreds of years to create mechanical energy for grinding, pumping and running machinery.|
|Wind Power is energy that is produced directly from the wind by using a wind turbine. Not only is this resource free and renewable, it also emits no harmful greenhouse gases.|
|Geothermal is heat energy from deep in the earth using special pipes buried underground. In some areas of the world steam is collected and used to turn turbine generators. In many areas pumps circulate water that is cooled in summer and heated water from the always-mild earth temperature several feet below the surface. This water is used in heat pumps that can cool and heat homes and buildings and can provide hot water.|