What is wind power?
Wind power is when we covert the power of the wind, physical energy, to more useful types of energy. The most common type of energy it is converted to is electricity.
A wind farm is a large area of land on which there are a number of wind turbines generating electricity, as a power plant does. When creating a wind farm one must make sure that the spacing between the turbine is sufficient as not to cause energy/wind loss.
HOW DOES IT WORK?
The most common type of energy generated from wind is electrical energy. This is by making the use of an electrical generator which is turned by turbine blades which are turned by the wind and thereby turning the turbine, creating electricity.
Is it renewable?
Yes, as we find wind throughout the world and the minimum wind speed needed is from 16km/h upwards. The wind needs to have a constant speed, should be non-turbulent and must not be subject to strong bursts of air. The wind also blows faster the higher into the atmosphere you go. That is why most wind farms are found quite high up.
APPLICATIONS OF WIND ENERGY
You get three types of wind farms:
On Shore
Near Shore
Off Shore
On Shore
If a wind farm is about three kilometres away from the nearest shoreline it is regarded as an on shore wind farm. They are normally installed in the mountainous areas as the higher you go the faster the wind blows. The cliffs and mountains also contribute to speeding up the wind. Before setting up a wind farm much research has to be done because the smallest diffenrence of placement could even double the turbines' output.
Near Shore
If a wind farm lies on land within three kilometres to the nearest shore line or lying on the water within ten kilometres from the shore it is considered a near shore wind farm. Sea shores tend to be very windy as the land and sea heat up and cool down at different rates, creating strong winds. The wind from the sea is also more dense and therefore carries more energy than the same speed wind in mountainous terrain.
Off Shore
If a wind farm is more than ten kilometres into the sea form a shore then it is considered to be off-shore. Off-shore turbines are found in deep sea waters and are usually much larger than their land-based siblings. The wind over the open sea is considerably faster and stronger than that of land because they have no obstacles in their way such as trees and buildings to affect the wind speed. Their distance from land allows companies to create larger ones and they do not need to worry about any noise factors as they are a considerable distance from the shore. The off-shore wind farms are the most expensive to build as they need to be set in the open ocean where they are subjected to all the earths's elements, therefore raising the maintence cost of off shore wind farms. The cost involved in transferring the electricity from the turbine to the land could be large as there is a large distance to be covered. Off shore wind farms are much larger than the on shore counterparts as there is much more space in the open sea as opposed to land and there are no worries of people complaining about them in the sea.
Airborne
This is a new concept with no product available as yet but there are companies busy developing an airborne wind turbine which is suspended high in the atmosphere thereby obtaining the fastest and strongest winds available.
ADVANTAGES
Wind is free and in abundance and we have the technology to capture the power of wind efficiently
The costs for wind turbines are only initial costs; once the turbine is built there are minimal maitenence costs which are involved.
In the rural areas which are not connected to a country's power grid it can be used to generate its own power.
The space which a wind turbine takes up on land is very small as the moving parts are quite a distance above the ground.
Wind turbines produce energy with minimal damage to the worlds environment and produces "clean power".
DISADVANTAGES
Some pollutants are given off into the atmosphere in the creation of a wind turbine.
Wind turbines can be quite noisy.
The wind speed is not constant and therefore there will not always be a definite supply of electricity form a wind turbine.
Large numbers of wind turbines are needed to power towns, as the largest turbine is able to produce electricity to sustain only +/- 500 homes.
Many people feel that wind turbines are unsightly and that they should not disrupt the natural beauty of landscapes.
WHAT IS NUCLEAR POWER?
Nuclear power is an alternative power source that uses the nuclear fission of uranium to create heat and, thereby, through a heat transfer mechanism and turbines, create electricity.
HOW DOES IT WORK?
For a nuclear reactor to create energy it is necessary for nuclear fission to take place. This occurs when an atom is split into smaller particles and an enormous amount of energy is released in the process. Uranium is used as the fuel for the reaction as it is radioactive, and is therefore unstable enough to be broken down into smaller parts. The uranium atom absorbs a neutron and splits into two equal parts and energy is created. This kinetic energy becomes heat energy as the particles slow down, and it is this heat energy, which is used to produce electricity (see Extras / Links for more information on the science involved). The heat is moved through a transfer medium, such as water, and is used to turn water into steam. This steam turns a turbine, which is connected to a generator. As the turbine turns the generator it creates electricity, which is then transferred to the consumers.
IS IT RENEWABLE?
Nuclear power is renewable as it doesn't use fossil fuels or other non-renewable resources in the production of energy; however it isn't as renewable as some of the alternatives, such as wind or solar power, which rely solely on natural phenomena to create their power. In the short term it is unlikely that uranium will run out, but eventually it will. Therefore we can say that nuclear power is only renewable in the short term.
APPLICATIONS OF NUCLEAR POWER
About 440 nuclear reactors are used around the world to produce about 17% of the world's electricity but in theory nuclear fission can be used for much more. At the end of the Second World War the Allies secured victory by dropping the atomic bomb on Japan. The bomb uses the same principles of splitting the atom as the nuclear reactors do in creating electricity. On a smaller, less destructive scale, the theories of nuclear fission are used daily in medicine. Scanning devices and the treatment of cancer both use the radiation from splitting an atom.
ADVANTAGES
As an alternative to normal coal-based electricity production nuclear power is favourable as it is much more efficient than coal (250g of uranium produces 20000 times more electricity than 250g of coal) and is far less polluting, especially to our atmosphere, as no harmful greenhouse gases are emitted. (ie. carbon monoxide, sulphur dioxide, nitrogen oxide etc.).
It is generally a reliable process that can be counted on to produce electricity for many years (average availability over three years is about 80%).
The amount of waste produced each year would cover only your dining room table!
The waste is stored in fire-, water-, and earthquake-proof capsules to ensure safety.
DISADVANTAGES
There is pollution in the form of radioactive waste but with new technologies the process is becoming cleaner and safer each year.
The possibility of radiation leakage or plant meltdown. This is possible in theory and has happened in the past (Chernobyl in Russia) but nowadays there are procedures in place to ensure safety.
There are problems and dangers, which could lead to accidents. The power stations are all manually run and human error could lead to possible accidents.
The reactors also have a very expensive capital outlay in the beginning, although the costs are cheaper in the long run.
The plants do require downtime for maintenance.
WHAT IS HYDRO POWER?
Hydro power is the process of changing the kinetic energy of flowing water in a river into electrical power that we can use.
HOW DOES IT WORK?
A dam is built where there is a natural lake or a big river in a valley. The dam is used to hold the water and create pressure so that the water can produce more electrical power. There is gravitational potential energy stored in the water and this energy is used to turn generators and create electricity. These turbines are within tunnels in the dam wall. Electrical generators are turned by these massive turbines and create electricity. Water flows through these tunnels with great pressure and is used to turn these turbines. The water has immense pressure due to the great height at which is kept in the dam. If there is a greater volume of water or there is a very large difference between the water level and where it flows out than you can get more power out of the water as it has greater potential energy. This difference in height of the water is called the head. The generator contains 2 main parts: the rotor and the stator. The rotator is the part which rotates and the wire has a huge magnet inside of it; and the stator is the part which is covered in copper. The electrical current is created when the rotor spins around the copper wire on the stator. This is the charge which is then used as electricity.
IS IT RENEWABLE?
It is renewable because the process takes nothing away from the environment and therefore nothing needs to be replenished. The water stays in the water cycle and can keep producing energy endlessly.
APPLICATIONS OF HYDRO POWER
Hydro power is also utilised by large scale companies as a private use. Many large mining companies or aluminium manufacturers use vast amounts of electrical so rather than buying from the state they can generate their own power by using hydro power generation.
ADVANTAGES
No pollution or waste produced
Renewable energy source
Very reliable energy source
Not expensive to maintain once the dam has been built
Can increase the plants production or decrease it whenever there is high or low demand
Water can be stored, waiting to be used in peak times
DISADVANTAGES
Building the dam is expensive and time taking
The dam will change the habitat and landscape upstream, as much more land will be submersed
The land below the dam is also affected as the flow of water is reduced
S
ilt
can build up in the dam as the water slows down it does not have
enough energy to carry the sand and silt which it was
