The energy is changed at various stages. The gravitational potential energy of water is changed into kinetic energy, which is then changed into kinetic energy of the turbines, which is finally changed into electrical energy of the generator.
Advantage
At night, when many more power stations have extra energy because it is not being used by people, the water is pumped back up again.
Disadvantage
A large amount of land has to be flooded, which could have been used for farming or forests.
How it works?
Wind energy, the fastest growing energy source in the world, works by using wind to turn its turbine. This then runs the generator to produce electricity. It is mainly used in open fields upon hills or near the coast, where wind will be free flowing best. It is mainly used in villages.
The energy is changed at various stages. Kinetic energy of wind is changed to kinetic energy in turbines, which is finally changed into electrical energy in the generator.
Advantage
While the wind blows the energy is free.
Disadvantage
The amount of electricity can vary depending on the strength of the wind, which can vary.
How it works?
Geothermal energy is a form of renewable energy derived from heat deep in the earth’s crust. This heat is brought to the near surface by thermal conduction and by intrusion into the earth's crust of molten magma originating from great depth. As groundwater is heated, geothermal energy is produced in the form of hot water and steam. The heated groundwater can be used for direct heating of homes and greenhouses, for vegetable drying, and for a number of other uses. These are known as direct uses of geothermal energy. The energy is changed at various stages; the heat energy from the rocks is changed into the heat energy of the water, which is then changed into the kinetic energy of the turbines, which is finally turned into electrical energy of the generator.
Advantage
The energy is free and it is available day and night.
Disadvantage
Only useful where there are hot areas of the Earth quite near to the surface.
How it works?
A large amount of energy is stored in the tides. The tides go in and out, and we can capture energy from this with tidal power stations. Tidal power stations can stretch over a delta, estuaries, beaches or other places that are affected by the tides. A barrage is first set across a beach or river. When high tide comes in, water flows through a turbine to create electricity. Now some of the water is up behind the barrage. A gate is lowered from the barrage, capturing the water above it. When low tide comes, the gate is raised and the water flows out, first transferring its energy through turbines. This way, electricity is created with a two-way turbine. The energy changes at various stages. The kinetic energy of water is turned into kinetic energy of the turbines, which changes into the electrical energy of the generator.
Advantage
Wherever there are tides, free energy is provided.
Disadvantage
Very expensive to build.
How it works?
The Salter Duck, Clam, Archimedes wave swing and other floating wave energy devices generate electricity through the harmonic motion of the floating part of the device, as opposed to fixed systems which use a fixed turbine which is powered by the motion of the wave. In these systems, the devices rise and fall according to the motion of the wave and electricity is generated through their motion. The kinetic energy from the water is changed into kinetic energy of the turbines, which is finally changed into electrical energy of the generator.
Advantage
Wherever there are waves, the energy is free.
Disadvantage
It only works in places where there are usually big waves.
How it works?
Solar energy, provided by the sun, is constantly replenished and will not produce harmful pollution unlike fossil fuels. Solar energy may be used passively; such as to heat and light buildings, or technology may be used to harness the sun's energy by collecting it and transforming it to generate electricity. Current technologies include photovoltaic, concentrating solar, solar hot water, and more. The light energy from the sun changes into electrical energy for the generator.
Advantages
Very good for producing energy in difficult to reach places.
Disadvantages
Not very efficient- lots of energy is wasted
How it works?
A nuclear power plant operates basically the same way as a fossil fuel plant, with one difference: the source of heat. The process that produces the heat in a nuclear plant is the splitting of uranium atoms. That heat boils water to make the steam that turns the turbine-generator, just as in a fossil fuel plant. The part of the plant where the heat is produced is called the reactor core.
Advantages
Can produce electricity at any time.
Disadvantages
If there is an accident, a large amount of dangerous radioactive material can escape into the atmosphere and seriously harm people over a very wide area.
