Renewable energy, is energy that is collected from a source which is replenished as quickly as it is extracted. Therefore, can never be used up. Most sources of renewable energy, such as sunlight, wind and water, are drawn from the natural environment

Solar Energy

Solar energy involves the use of sunlight to generate electricity. There are two commonly used methods to generate energy from the sun. Solar Cells, and a solar powered turbine.

Solar Cells

The most commonly used solar cell uses a semiconductor (usually silicon) to generate electricity. As particles of light, known as a photon, hits the electrons on the atoms of the semiconductor, they are knocked out of orbit and onto a metal strip that runs through the cell. This conductive strip then carries the electrons down into the wires where they are used. The electrons are then replaced by molecules in the air and the cycle can begin again.

Current solar cell technology requires a large amount of space to generate a sizable charge, but there is a new type of solar cells which could change that.

Solar Powered Turbine

This system created by BrightSource Energy, is similar to a nuclear power plant. Large mirrors are used to heat pipes of pressurized synthetic oil, this oil is then passed through a heat exchanger and send back out to be re heated. Water within the heat exchanger is converted to steam which turns a turbine to create electrical energy. The steam is then condensed and reused to fuel the turbine once again.

This method is often referred to as a double loop system because it contains two circuits of fluid.

Hydroelectricity

A hydroelectric plant uses water to generate electricity. Normally, these are set up in an area where natural forces allow the water to flow, like a river. As this water follows its natural course, it turns a shaft which then moves a turbine to generate electricity. The faster the water moves, the more energy is generated.

Wind Energy

A Wind farm generates electricity by using the forces of the wind. When the wind hits the blades, the force causes them to rotate these blades are connected to an axle which turns a turbine to generate electricity. Like hydroelectricity, the amount of energy generated is relative to the speed of the turn.

Geothermal Energy

Geothermal energy harnesses the heat that is generated by the planet. In Australia, research is going into hot rock technology. Hot rock technology uses hot granite to heat water. This heated water is then used to turbine. This can be done directly or through a heat exchanger.