Ways to generate electricity

Burning fossil fuels:

Brief description of what it is: Dead organisms get buried under the ground so they get squashed over time and the pressure changes their state to the fossil fuels we know as coal, crude oil and natural gas.

How it harnesses energy: When you burn the fossil fuels they heat up water which evaporates into steam, and therefore driving the turbine. Indirectly harnesses energy.

Advantages:

Cheap and reliable, we have been using them for centuries

Disadvantages:

Releases carbon dioxide which adds to global warming
Sulpher dioxide produced (from coal especially), reacting with water and oxygen to make acid rain
It's not renewable

Nuclear Power

Brief description: Getting energy from the energy stored in atoms.

How it harnesses energy: We split the atoms and that releases lots of heat energy. This heats up the water and the steam turns the turbine. This process is called fission. Indirectly harnesses energy.

Advantages:

Is clean energy as emits no Carbon Dioxide,
Small amount of fuel needed to supply a large amount of energy
High energy density fuel
One kilogram of Uranium is the same as one tonne of coal

Disadvantages:

Non renewable
Radioactive waste- can cause cancer

Solar Power

Brief description: Harnessing energy from the sun

How it harnesses energy: Instead of using a turbine, we use solar cells to convert the sun's energy. Neither direct or indirect as doesn't use a turbine.

Advantages:

No greenhouse gasses
Once you've built it, it's free
Renewable

Disadvantages:

Unreliable
The amount of electricity you generate is dependent on the time of year, time of day and where you are.

Wind Power

Brief description: Wind power has been around for a long time, e.g. windmills. Blades turn from the wind which drives a small turbine inside.

How it harnesses energy: Huge blades on a tall tower. The blades are connected to housing which contain gears linked to a generator. When the wind blows, it transfers some kinetic energy onto the blades which turn to drive the turbine. Directly harnesses energy.

Advantages:

Wind is a renewable energy source.
No fuel costs.
No harmful polluting gasses are produced.

Disadvantages:

Some people may think that the are ugly or noisy and disrupt the countryside.
The amount of electricity generated is dependent on how much wind there is. No wind = no electricity.

Geothermal energy

Brief description: All about the heat underneath Earth.

How it harnesses energy: About four feet under the ground the temperature stays the same at 55 degrees C, there is liquid there with the same temperature. Pipes under the ground at four feet deep pump that liquid to a device called a 'heat exchanger' which takes the heat from the liquid and pumps in into the air at home. A geothermal heater is also able to cool the home down by simply absorbing the hot air and moving it back under the ground.

Advantages:

Minimizes air pollution
Renewable energy source
Energy efficient
Almost no energy is wasted so helps keep heating bills down.

Disadvantages:

High installation costs
Hard to transport
May release harmful gasses
Only suited to particular areas

Biofuels

Brief description: Biofuels are designed to replace petrol, diesel and coal. There are three main types: ethanol, biodiesel and biotech fuel. Ethanol is used in cars, bio diesel in trucks and biotech fuel in planes.

How it harnesses energy: The biofuels are grown in fields. When they are fully grown they are burned, which releases steam and drives the turbine. Indirectly harnesses energy.

Advantages:

It is carbon neutral- it doesn't reduce nor produce Carbon Dioxide. In this case, when the plant is burned it produces CO2 but the plants in the field absorb it through photosynthesis.

Disadvantages:

Biofuels use 2-84 times more water than regular crops
Threatens the food supply- as more fields are used to grow biofuels, there are less fields to grow crops, putting food prices higher.

Hydro-electric power

Brief description: Uses pumped storage. Has a pump to bring the water at the bottom back to the top. Pumped at night as no one is using it while they're sleeping.

How it harnesses energy: A dam is built to stop the water from flowing down. When the dam is lifted, the water flows down to turn the turbine. Indirectly harnesses energy.

Advantages:

Renewable
Reliable
Clean energy
Safe to use
Can adjust water flow

Disadvantages:

If there's a drought there's no more electricity
Can only work in certain places.

Tidal Power

Brief description: Happens at very specific times of the day. Waves by the sea come in, and then go back out again.

How it harnesses energy: There's a turbine in the sea. As the wave comes in and out it drives the turbine. Directly harnesses energy.

Advantages:

Really predictable
Really reliable

Disadvantages:

In land lock countries this isn't possible.
Sometimes intensity is too much and it can break the generator
Only happens twice a day.

Wave Power

Brief description: Wind blowing across the surface of the water to generate electricity.

How it harnesses energy: There are harnessers sitting on the surface of the water. When the wave hits the harnesser it hits all the others and turns the turbine. Indirectly harnesses energy.

Advantages:

No damage on land
Quite reliable

Disadvantages:

Damages sea life
Problems with shipping?

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Information on generating electricity, including fossil fuels, nuclear power, solar energy, wind power, geothermal energy, biofuels, hydro-electric power, tidal power and wave power. :)