RENEWABLE ENERGY
Renewable Energy is also known as "green power" or "clean energy", because it doesn't harm the environment and it is made from resources that Mother Nature will replace, these sources include Solar energy (which comes from the sun and can be turned into electricity and heat), Wind energy, Geothermal energy (from inside the earth), Biomass from plants, and Hydropower from water.
Hydro Power
“Hydro” means “water” in Latin – so “hydro power” is made from water.
You might be wondering how we can use water to make electricity as they are a dangerous combination, right? Actually, the water never comes in contact with the electricity. The water flowing down a river is used to spin the turbines inside the generator.
Unlike other renewable sources like the sun or wind, water can be stored which makes it a great way to create electricity.
Rivers, dams and waterfalls can be used to generate hydro-power. Hydropower stations are built where there is running water. The most common are located in dams, where water is stored.
Solar Energy
If you have ever used a magnifying glass to make something melt or burn? You were using solar power!
“Solar” is the Latin word for “sun” – and it’s a powerful source of energy. The sun provides energy in two forms – light and heat. The sun can be used to heat water and air in our homes and businesses (If you’ve seen a house with big shiny panels on the roof, that family is using solar power.). It can also be used as an energy source to produce electricity.
The process of making electricity using solar energy is called photovoltaics. If you have a solar-powered watch or calculator, you’re using photovoltaics! Electricity can be produced directly from solar energy using photovoltaic devices or indirectly from steam generators using solar thermal collectors to heat a working fluid.
Solar energy falls into two main categories:
"Solar photovoltaic" energy
Photovoltaic (fo-to-vol-ta-ik) systems are solar systems that produce electricity directly from sunlight. The term "photo" comes from the Greek "phos," meaning light. "Voltaic" is named for Alessandro Volta (1745-1827), a pioneer in the study of electricity for whom the term "volt" was named. Photovoltaics, then, means "light electricity." Photovoltaic systems produce clean, reliable electricity without consuming any fossil fuels. They are being used in a wide variety of applications, from providing power for watches, highway signs, and space stations, to providing for a household's electrical needs.
"Solar thermal" energy
Energy from the sun is absorbed and used to heat things like water. The hot water can be used directly or it can be used to create steam to drive a small turbine which generates electricity. There are not many working examples of this in Australia but there has been a lot of research into it. Solar hot water falls into this category also.
Wind Energy
Wind simply put is moving air. It is created when the sun heats the air and cooler air moves in to replace it. This causes wind. Through the ages people have learned to harness the wind's energy. Like the sun, it can also be used to create electricity.
Windmills are used in many countries to capture the wind's energy. The moving sails of the windmill are connected to wheels that turn to operate machinery. The machinery is used "to grind" the wheat and other grains into flour or to pump the water from place to place to help irrigate the land. The term windmill comes from "to mill" – meaning "to grind".
The energy from turning windmills can also be used to drive turbines which generate electricity. Wind energy is useful for making electricity because it is a renewable resource and does not create pollution or cause damage to the environment.
Wind turbines feature a number of components, including blades, a shaft, a generator and a tower. The blades look like propellers, except that instead of creating wind, they catch the wind.
The shaft is connected to the blades, and it rotates as the blades turn with the wind. The shaft runs to the generator. The generator transforms the rotations of the shaft mechanical energy into electrical energy.
Geothermal Energy
"Geo" means "from the earth," and "thermal" means "heat," so this type of energy is energy from the heat of the earth.
Geothermal energy is a renewable energy source because the heat is continuously produced inside the Earth.
We can also use geothermal energy to make electricity. A geothermal power plant works by tapping into steam or hot water reservoirs underground; the heat is used to drive an electrical generator.
Biomass
Biomass energy uses natural materials like trees and plants to make electricity. The food you eat, plants that die, wood chips and seaweed are all sources of biomass energy.
Most rubbish we throw out is buried in the ground (also known as landfill). The gas generated by landfill as it rots (biomass) is another form of renewable or "green" energy.
This gas would normally just seep through the ground and into the atmosphere, contributing to environmental problems. However, it can be captured and processed to create electricity. It is collected, dried (to get rid of any water), and then filtered (to get rid of any waste particles). It is then fed through pipes to a gas generator that burns the gas to create electricity.