Energy Sources And Power Stations

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  • Created by: Samb0y
  • Created on: 26-05-14 17:48

Energy Sources

There are 12 different types of energy resource.
They fit into two broad types: Renewable and Non-Renewable.

Non-Renewable - this basically means that they will run out eventually, if we continuously use them, we will eventually run out of them. There are 4 Non-Renewable resources and they are:
1 - Coal (Fossil Fuel)
2 - Oil (Fossil Fuel)
3 - Natural Gas (Fossil Fuel)
4 - Nuclear Fuels (Uranium and Plutonium)

Renewable - this means that we will never run out of this resource, no matter what, they will always be present on our earth somewhere. They are:
1 - Wind
2 - Waves
3 - Tides
4 - Hydroelectric
5 - Solar
6 - Geothermal
7 - Food
8 - Biofuels

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How We Make Electricity

Unfortunately, most of the energy we see around us comes from Non-Renewable power plants (coal, gas oil and nuclear). Now, coal, gas and oil are all used in the same way to create electricity. (Look up 'How Fuels Are Burnt To Create Electricity').

Nuclear energy is unique and is used differently to create electricity (but it still works on the same principle! The only difference is the way in which the steam is created (Look up 'How Fuels Are Burnt To Create Electricity').

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Renewable Energy Sources - Wind

  • Wind energy is probably the most useful but most temperamental.

Wind power involves putting loads of wind mills (scientifically called wind turbines). They work and are effective:
1) Build The Turbine (Obviously) - You need to also consider where the wind turbine is going to be out. You don't want to put it in the middle of the amazon rainforest where tress are going the block the wind. Normally they are placed in the country side, near the sea or high up.
2) Connect The Turbine To The Power Grid - Normally all the wind turbines are interlinked and will all go to a power station where the power can be directed through to the national grid.

How they work - The wind blows across where the turbines are located. The wind turns the turbines "arms" which is attached to a generator which then turns the kinetic energy into electrical energy.

Pros:
It doesn't pollute (except for when they are made).
They rarely malfunction.
Cons:
You need a lot of them to create a sufficient amount of energy (1500 = coal power station).
Many people refuse to have them built near them due to noise and ugliness.

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Renewable Energy Sources - Solar Cells

Solar cells are used to turn energy from the sun (solar energy) into electricity. First things first, solar cells create electricity, solar panels heat water up... DON'T GET THEM CONFUSED.

Solar cells generate electricity directly from sunlight. Even though solar cells are often put on top of houses they are much better for calculators and watches due to the fact those items are low power. The think with solar cells is that they only have an efficiency of about 10%.

Solar cells are often put in places where there's no choice but to put them i.e. The Australian outback or on road signs which are placed in the middle of nowhere.

Pros:
They rarely malfunction because the technology is quite basic.
They generate enough electricity to power small scale items (biggest is an individual house).
You can receive government grants to build them.
Electric companies will buy the electricity off you in you generate more than you need.
Cons:
They cost a large amount of money (even with the government grant) and it takes an average of 25 years before you make your money back.
To connect them to the national grid is expensive and not very practical.

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Renewable Energy Sources - Hydroelectric

Hydroelectric involves the flood of a valley by building a damn to stop the water in rivers flowing down stream. As you can imagine, there are a lot of problems with this but hydroelectric is very resourceful and an effective way to create electricity.

How they work:
Rainwater is caught and allowed to build up until eventually it's allowed to be released down the damn where the water with flood past the turbine which will turn the generator.
Hydroelectric is a very successful way to provide electricity to remote ares such as towns and villages. Because there is no limit on how big the valley can be and how big the damn is, it's a great way to provide electricity to large or small scale areas.

Pros:
They can provide and immediately response to a demand in electricity i.e. somewhere near a damn is running low on electricity, the damn can be used to get the village electricity.
It's pollution free because it doesn't burn any fuels.
They are reliable.
Cons:
The initial cost to build one is very high.
They're very reliable unless if there's a drought (not a problem in Great Britain).
They can destroy habitats due to the amount of land that needs to be flooded to support it.

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Renewable Energy Sources - Pumped Storage

Most large power stations have to be kept running due to the fact that the start up time makes it impossible to provide electricity for people if there's a sudden and un-expected demand in electricity. Because electricity is continues to be generated through the night, spare energy increases. Unfortunately spare energy surprisingly very hard to store. Pumped storage is one of the great ways of storing energy.

How does it work:
At night, when most people are asleep and electricity levels are considerably higher than in the day, pumped storage power plants will be used. They work by pumping water which has been collected behind a damn up to a higher reservoir (a pump does this and pumps require electricity to work).

Now of course, you wouldn't use this method when electricity is on demand due to the fact that the pump used a significant amount of energy as well. Obviously this isn't a way of generating electricity. This method is useful because it allows you to use up electricity when there's an excess but also create it when there's not enough.

Pros:
It is a reliable method of using/generating electricity.
It's a way of storing electricity.
Cons:
It doesn't create electricity, it must simply stores in a form of water.
They often malfunction due to the stress and weight of water.

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Renewable Energy Sources - Waves

Now, wave power works on the same basic principle as hydroelectric and pumped storage but also has a similarity with wind turbines.

The similarity with hydroelectric and pumped storage is that wave power relise on water turning the turbine creating electricity in the generator.
The similarity with a wind turbine is that wave power generators are called 'wave-powered turbines'. This is important because it looks very similar to a wind turbine but powered differently (the element of wind is replaced with waves).

Wave turbines are effective due to to the simple fact that even the slightest of waves will generate a small amount of electricity. And as we know, the sea is rarely still (not even the slightest lapping in the waves).

Pros:
They are cost effective.
There is no pollution.
There is no cost to run them.
Cons:
Initial cost to build them is high.
People often complained about the view being spoiled by them.
They are a danger to boats and swimmers.

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Renewable Energy Sources - Tidal Barrages

Hopefully, you know the tide relies on the gravity asserted on the earth by the sun and moon. Because the moon and earth follow a predictable orbit, we can calculate tides (sometimes up to a hundred years in the future).

Tidal barrages are big damns built across river estuaries with turbines in them. As the tide rises, the damn will hold back the tide, letting it rise to several meters before the damn will open its flood gates. The water slowly (sometimes quickly as well) floods through the flood gates where the turbines are turned by the rushing water. Tidal barrages work on the same principle as a damn but is just basically a damn placed in a river estuarine.

Pros:
It's reliable and predictable.
It can be controlled so not to much land is flooded.
It's involves no fuel so is relatively cheap.
Cons:
Of tides are equal on both sides, it won't work.
Sometimes tides are smaller than predicted.
If the flood gates break and are closed, they're hard to fix and can flood large amounts of land.

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Renewable Energy Sources - Geothermal Power

Geothermal is an incredibly effective and increasingly used way of producing electricity. Geothermal relies on heat (that's why it's got thermal in its name) but not ordinary heat, the heat of rocks (why there's Geo in it). Geothermal basically means 'hot rocks'.

How it works:
1) A power plant has to be built where their is hot rocks near the surface of the earth (about 7km down).
2) Pipes are built down to where the hot rocks are, one where water can be pumped down and one where steam can rise.
3) Cold water is pumped down one of the pipes where it makes contact with the rocks. Because the rocks are the natural process of slow decay of various radioactive elements. Because this generates large amounts of heat, it evaporates the water which rises up the second pipe.
4) The steam pushes past the turbine (causing it to turn) which generates electricity.

Pros:
Very effective.
Reliable due to rocks will generate heat for years (until volcanoes becomes extinct).
Cons:
Its expensive due to sourcing the water.
It's very dangerous because they're built on dormant or active volcanoes.

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Renewable Energy Sources - Biofuels

Biofuels work on the exact same principle as coal, oil and gas. They're all similar due to the fact that they are burnt to heat waters which turns and turbine which powers a generator creating electricity.

The Difference?
The difference with biofuels is that it is classed at carbon neutral. This is due to the fact that biofuels is just burnt plant material. Plants take in carbon dioxide. And when they're burnt they release the exact amount back into the atmosphere. This means no extra carbon dioxide is created.

The Cons:

  • Unfortunately the plants needed to create biofuels need extra help to grow which means they need a fertiliser (horse manure) which contains large amount of methane. The plants absorb the methane and when burnt, they release the trapped methane into the atmosphere as well.
  • There's a lot of transportation involved and because most cars still run on fossil fuels... It could be argued it's no as carbon neutral as people think.
  • It also reduces the food market, making food prices go up (if farmers swap from food farming to farming products for biofuels).

Pros:
Renewable.
Cheap to maintain.

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Carbon Capture - Part 1

Now, we have a growing problem with the amount of carbon dioxide we produce by burning fossil fuels. But, a very smart way to combat this has been created. The method is called 'carbon catching'.

What is 'carbon catching'?
Carbon catching is basically what it says in the name. When a fossil fuel is burnt, you literally catch and store the carbon.

What happens to the carbon?
When the carbon is stored, it can be pumped into greenhouses. This is effective because plants thrive in the carbon dioxide environment. Of course the gases have to be cleaned of particulates and sulfur and other 'nasties'.

Am example:
In some places around Britain, power plants are linked to tomato farms. The carbon dioxide is pumped into the greenhouse to the tomatoes. This lets tomatoes grow at a rapid rate (as quick as three days).

Unfortunately, when a plant grows at such a fast pace, they don't have long enough to develop the rich nutrients we need. So you need to eat more to get the right amount of nutrients.

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Carbon Catching - Part 2

Another way is to store carbon is by dissolving it in water and storing it at the bottom of oceans. The problem with this... Is that carbon dioxide is slightly acidic and if you store to much in the sea, it can effect calcium carbonate shell based creatures (crabs and sea snails) and can raise the acidity of the sea (dangerous to all life).

You can also store it in water with a huge amount of algae. The algae will use the carbon dioxide and thrive in the rich environment. And then they can be turned into oil with can be used as a biofuel. This way isn't using up the carbon dioxide though, it's just prolonging its release into the atmosphere.

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