Renewable Energy are sustainable energy resources that have no life expectancy. This means they are infinite and we can continue to create energy from them forever.
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Why we need Renewable Energy
Renewable energy sources are infinite and can continuously be created and used. Unfortunately, at the moment the majority of power and energy used in the UK is from non renewable resources such as oil, gas and coal. Non renewable resources are created naturally and take millions of years to develop. However, we use them faster than they can be produced which means they are fast running out. Because of this, the world has started looking into alternative forms of energy using renewable resources. This has lead to the development of wind, wave, tidal and solar energy. Each energy type has its pros and cons and you can find out more about them here.
Wind power has been around for thousands of years. It was once used by the Chinese to power a water pump to water crops and in Europe to ground corn.
Wind Power Methods
When the sun heats up the atmosphere of the Earth it doesn’t do it evenly which means some parts will become warmer then others.
The warmer sections of the atmosphere rise and colder air moves into the empty space, this movement causes a blow of air which we know as wind.
We can then use this kinetic energy to turn a large propeller which is placed on top of a large tower. When the wind energy turns the propeller it will create electricity.
You will usually see a few of these towers together when driving near the coast this is because the wind farms need to be placed in an area which has a constant supply of wind. Therefore coastal areas and out at sea are ideal locations for wind farms.
It is also not uncommon to see boats and caravans with a small wind turbine on the top to help keep their batteries charged.
Pros and Cons of Wind Power
Wind Power has the potential to create a large amount of power for the world. However, the method has its advantages and disadvantages:
Positive aspects of wind power:
- Wind farms do not use fuel to generate electricity so no greenhouse gases are released during the process.
- The wind turbines do not ruin the ground they are built on.
- Wind farms can be used to provide electricity to remote areas.
- Wind doesn’t cost anything to produce.
- Wind is renewable and will always be available.
Negative aspects of wind power:
- The main problem with wind towers is that wind cannot be predicted and on some days there may be no wind at all.
- Wind towers can harm and even kill birds if they manage to fly into propellers. However, this is not very common.
- Wind turbines can generate some noise. This can be irritating to residents living near the turbines. However, newer wind towers are being developed to make them quieter and less intrusive.
- Some people consider wind farms an eye sore and do not like the look of them.
Waves in the sea are the result of the wind blowing across the surface of the sea. Waves are constantly forming in the sea so its an unlimited supply of power. Even if you see a calm sea there will still be an undercurrent which can be harnessed to produce electricity.
Wave Power Methods
There are four ways we can harness the power of the ocean waves to produce electricity, they are:
1. Wave Power Plants
A wave power plant is built on the ground next to the sea. It has a chamber reaching out into the sea and when the waves enter the chamber it pushes the air up at speed. A turbine is placed at the top and the moving air will turn the turbine and then the turbine will turn a generator behind it.
It works in a a similar way to wave machines you find in swimming pools, the only difference is it is reversed; instead of blowing air into the chamber to push the sea down and create waves the water enters the chamber and pushes air out.
2. Pelamis Wave Power
The Pelamis Wave Power company have developed an offshore method of collecting energy from the ocean waves using a floating snake like tube (a Pelamis).
The Pelamis tube is around 375ft and is made up of around 5 hinged sections. The tube will be placed in the water and attached to the side or anchored to the floor and left there to float with the waves. The waves will cause the tube sections to move up and down and as the hinges between the sections bend they pump hydraulic fluid and then the fluid will turn the generators.
3. CETO Wave Power
A company called Renewable Energy Holdings have developed a product called CETO to harness wave power.
The CETO will be built underwater close to the coast. When waves pass across the top of the structure it will make a piston movement which will then pump the sea water, this energy will then power a generator on the land.
4. The Oyster
The Oyster is built underwater and utilizes the power of the waves to pump hydraulic fluid to shore.
The Oyster looks similar to a book, imagine opening and closing a book and this is exactly how the Oyster works. When the Oyster is forced open it pulls in the fluid and then when it is forced closed it pushes the fluid through a tube and to the shore to power a generator.
These four examples are not the only ways we can draw energy from the ocean waves, in fact there are new ideas to draw the energy from waves being proposed every year. These are just a few of the ways waves can be used to create electricity.
Pros and Cons of Wave Power
Here are the advantages and disadvantages of wave power:
Positive aspects of Wave Power
- Like wind energy, no fuel is used to harness energy from the waves so there is no waste product produced from the process.
- Wave power has the potential to produce a lot of energy.
- Wave power is fairly cheap to run and maintain.
- Wave power is suitable for small countries surrounded by water such as the UK.
Negative Aspects of Wave Power
- In some areas close to countries there are not that many waves.
- The devices must be able to hold up against the harsh environment in the sea.
- They need to be placed in an area where the waves are strongest and more constant.
- As wave power is created out at Sea, it may be developed a long way from the coast so takes a lot of effort to transport the energy.
- Construction of wave power turbines is expensive.
- Some conservationists oppose wave power techniques as they impact natural environments.
The coastal tide moves an enormous amount of water two times each day, if we could successfully harness the power it could potentially provide the UK with 20% of its electrical needs.
Tidal Power Methods
There are a few ways we can potentially use the tidal power to produce electricity these include:
These work in a similar way to hydro-electric dams except these tidal barrages are much much bigger.
The tidal barrage is built in front of a river estuary, the barrage allows water to pass through it when the tide comes in and goes out.
The movement of the water passing through the barrage causes the turbines to turn, a tidal barrage can also be set up so instead of the water turning the water could push air through pipes which would then turn the turbine.
Offshore turbines are a lot cheaper than a tidal barrage and they are more environmentally friendly.
Offshore turbines are basically wind turbines but underwater, they look the same and use the same way of generating electricity. The only difference is instead of using wind to turn the propeller it uses the flow of water from the ocean. These are better than tidal barrages because even when they are out of the water they can still spin thanks to the wind.
Tidal reefs look similar to tidal barrages, but they are not the same. Tidal reefs do not stop the flow of water as much, which means it will not cause too much damage to the environment because the tides will still be able to come in and out easily.
A tidal reef allows fish to pass and the mud flats will still be exposed when the tide goes out. It will also be able to generate power for a longer amount of time.
Pros and Cons of Tidal Power
As with other forms of renewable energy, tidal power has its advantages and disadvantages:
Positive Aspects of Tidal Power
- Tidal power also uses no fuel to produce energy and does not release greenhouse gases.
- Technology can be used to predict tide patterns.
- Tidal power is almost free to create,although it can be expensive to set up the technology.
- Tidal energy has the potential to create a huge amount of energy for small islands like the UK.
- Tidal barrages can be used to prevent floods.
- Tidal barrages can be used as bridges.
Negative Aspects of Tidal Power
- When waste is put into the sea it is usually taken away from land with the tide, but if there is a tidal barrage it will hang around for a lot longer.
- Barrages stop the tide from coming in and out as fast so there is more pressure. This can cause damage to some wildlife. Birds usually feed on the mud flats when the tide goes out, if a barrage is there it will take a lot longer for the tide to go out.
- The tide only goes in and out once a day which means water is only passing the tidal barrage for 10 hours. However, the tide usually comes in and out around the same time each day so it would be easy to get other power stations to supply power over the period of time when the tide is not moving.
- There are not many suitable places to build a tidal barrage.
- Tidal power constructions are expensive to build.
Hydroelectricity has been around for a a long time, in fact the first house to be powered only by hydroelectricity was built in England in 1878
Now in the 21st century hydroelectricity power stations provide in the region of 20% of the world’s electricity
Hydroelectric Power Methods
Hydroelectricity is produced by building a dam in a valley where there is already a lake. Water is then allowed to pass through the bottom of the dam. Flowing water then turns the turbines which powers the generators.
Dams rely heavily on gravity, because the dams are so high and the water is so deep the gravity pulls the water and when it passes through the dam it passes at high pressure. This high pressure water creates a lot more energy, this is why we continue to see higher and higher dams being built.
Pros and Cons of Hydroelectric Power
Here are the advantages and disadvantages of hydroelectricity as a form of power:
Positive Aspects of Hydroelectric Power
- There is no pollution or waste produced from the process of creating hydroelectric power.
- Electricity is constantly created.
- Water can be allowed to build up ready for peaks in usage.
- Hydroelectricity is a very inexpensive once built and is clean way to produce electricity
Negative Aspects of Hydroelectric Power
- When a dam is built it causes a flood upstream which will cause some animals to become homeless and distressed.
- It could affect the water quality after the water has been through the dam.
- Finding the perfect site for a dam can sometimes be difficult.
- Hydroelectric stations are expensive to build.
The sun is the most powerful thing in the universe and if we could harness its power properly we would have enough energy to power the whole of the Earth for a whole year from just a few minutes of energy from the Sun.
Solar Power Methods
The three main ways we currently harvest the energy of the Sun are:
Solar panels perform best in a warm, sunny climates. With just one two square metre you will be able to power any appliance up to 200W.
Solar panels are becoming increasingly popular in the UK due to new government schemes. The government will pay you for any extra electricity you produce and feed back into the national grid, this is called the ‘feed in tariff’
Some companies also offer to pay for the panels for you if they can keep and sell any extra electricity you produce.
Solar water heating
Solar water heating is fairly simple, it will pump water through black pipes and into a glass tube where the sun will then heat up the water. The hot water will then be pumped into your home for heating.
Solar water heating can dramatically decrease your energy bills each year, especially in hot countries. Though in the UK with the latest advances in technology it has become very worthwhile to get these installed. New technology doesn’t actually need heat from the sun to heat up the water, it can heat the water from IR to UV, this means that even from the smallest amount of sunshine your water can be heated. The manufacturers actually claim to be able to supply 90% of your hot water needs from April to November in the UK!
If as a child you ever got a magnifying glass and burnt some leaves using the light from the Sun, then you will know exactly how this works. If you concentrate any of the energy from the Sun into a small area then you will be able to achieve very high temperatures.
In Odeillo, France, they have built a solar furnace that can achieve staggering temperatures of up to 3,000 degrees Celsius.
Pros and Cons of Solar Power
Here are the advantages and disadvantages of solar power:
Positive Aspects of Solar Power
- Solar power is free and produces no waste or pollution.
- It is ideal for low power appliances like lights and chargers.
- Solar power ca reduce people’s hot water bills greatly.
- It has higher potential in hot countries.
- Individuals can fit their own solar panels to their house to create their own energy and become self sufficient.
- Excess energy created on individual dwellings can be sold back to the government.
Negative Aspects of Solar Power
- Solar panels can be expensive to install but they are always falling in price due to technology advances.
- They are not as effective in colder countries, but they are getting better thanks to technology.
- There is no sun at night time so no energy can be created overnight.
- Solar panels can be expensive to manufacture.
- Solar Panels can be expensive to fit.
- Solar panels may not be aesthetically pleasing to some people.