Energy comes from a Power Source. There are many types of power sources, but most energy we use today comes from an energy source known as "fossil fuels." Coal, crude oil, and natural gas are fossil fuels. These substances were formed when ancient plants and animals, like the dinosaurs, died. As their bodies decayed they were mixed with the sand and mud and buried deep in the earth. Compression and heat over millions of years changed them into substances that we can burn as fuel.
Let's take a look at the types of power sources that are used:
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 to high temperatures, the oil can be extracted.
Wood and Coal are also used to produce electrical, mechanical, 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.
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 channeled to a turbine or water wheel. The force of the flowing water turns the turbine or wheel, which turns a generator to make electricity. Water power has been used for hundreds of years to create mechanical energy for grinding, pumping and running machinery.
Sun Power (solar energy) gives us heat and light energy. The sun makes energy from nuclear fusion. Hydrogen atoms collide with each other billions of times each second and produce helium. Every second, 4.7 million tons of hydrogen become energy.
Solar photovoltaic cells use sunlight to produce electricity that can be used directly or stored in batteries for later use.
Nuclear Power is used to make electricity. Inside a nuclear reactor, atoms from a fuel called uranium are split by neutrons (nuclear fission). This energy is released as heat, which changes water into steam, which then turns turbine generators.
Wind Power is used for mechanical and electrical energy. Wind has been used for thousands of years to help ships sail and turn windmills to pump water for irrigation.
Geothermal is heat energy from deep in the earth that is collected using special pipes buried underground. In some areas of the world, steam is collected and used to turn turbine generators. In other areas, pumps circulate water down several feet below the surface into the always-mild earth temperatures, where the water is cooled in summer and heated in the winter. This water is used in heat pumps to cool and heat homes and buildings and can also provide hot water.
Biomass is energy that comes from plants and organic matter such as wood, crops like corn and sugarcane, manure, aquatic plants. Even landfill gas from garbage and sewage provide a source of fuel that can be burned to release its stored energy to make electricity. Other products from biomass include liquid and gaseous fuels, heat, and other chemicals. Biomass is a "renewable fuel," which helps reduce the use of non-renewable fossil fuels.