Energias Alternativas

Coal, Oil and Gas are called "Fossil Fuels"

Introduction
Coal, Oil and Gas are called "fossil fuels" because they have been formed from the fossilised remains of prehistoric plants and animals.

How it works:
Coal is crushed to a fine dust and burnt. Oil and gas can be burnt directly.
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More Details:
Coal provides around 28% of our energy, and oil provides 40%.
This can belargely avoided using "flue gas desulphurisation" to clean up the gases before they are released into the atmosphere. This method uses limestone, and produces gypsum for the building industry as a by-product. However, it uses a lot of limestone.
Crude oil (called "petroleum") is easier to get out of the ground than coal, as it can flow along pipes. This also makes it cheaper to transport.
Natural gasprovides around 20% of the world's consumption of energy. It is easy to transport along pipes, and gas power stations produce comparatively little pollution.

Advantages
• Very large amounts of electricity can be generated in one place using coal, fairly cheaply.
• Transporting oil and gas to the power stations is easy.
• Gas-fired power stations are very efficient.
• Afossil-fuelled power station can be built almost anywhere, so long as you can get large quantities of fuel to it. Didcot power station, in Oxfordshire, has it's own rail link to supply the coal.
Disadvantages
• Basically, the main drawback of fossil fuels is pollution.
Burning any fossil fuel produces carbon dioxide, which contributes to the "greenhouse effect", warming the Earth.
•Burning coal produces more carbon dioxide than burning oil or gas.
• Burning coal produces an acidic gas that contributes to the formation of acid rain.
• Mining coal can be difficult and dangerous.

Fossil fuels are not a renewable energy resource. Ok, you could argue that fossil fuels are renewable because more coal seams and oil fields will be formed if we wait long enough.However that means waiting for many millions of years. That's a long time.

Nuclear Power - energy from splitting Uranium atoms

Introduction Nuclear power is generated using Uranium, which is a metal mined in various parts of the world.
Nuclear power produces around 11% of the world's energy needs

How it works
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More details
The fuel arrives encased in metal tubes, which arelowered into the reactor whilst it's running, using a special crane sealed onto the top of the reactor.

Advantages
• Nuclear power costs about the same as coal
• Produces less pollution than fossil fuels.
• Produces huge amounts of energy from small amounts of fuel.

Disadvantages
• Although not much waste is produced, it is very, very dangerous.
It must be sealed upand buried for many years to allow the radioactivity to die away.
• Nuclear power is reliable, but a lot of money has to be spent on safety

Nuclear energy from Uranium is not renewable. Once we've dug up all the Earth's uranium and used it, there isn't any more.

Solar Power is energy from the Sun

Introduction
We've used the Sun for drying clothes and food for thousands of years,but only recently have we been able to use it for generating power.

How it works
There are three main ways that we use the Sun's energy:

▪ Solar Cells (really called "photovoltaic" or "photoelectric" cells) that convert light directly into electricity.
Sun photoelectrics cells electricity
In a sunny climate, you can get enough power to run a 100W light bulb from just one squaremetre of solar panel.

▪ Solar water heating, where heat from the Sun is used to heat water in glass panels on your roof.
Sun glass panels heat black pipes hot water
Water is pumped through pipes in the panel.
The pipes are painted black, so they get hot when the Sun shines on them.
You must remember to drain the water out to stop the panels freezing in the winter. so Solar...