Name the types of power stations that release carbon dioxide into the atmosphere
Coal, oil and gas-fired power stations
Name the type of power station that does not release carbon dioxide into the atmosphere
Nuclear power station
Give one disadvantage of nuclear fuel compared with other fuel types
Nuclear fuel produces radioactive waste, which must be stored for many years until it becomes non-radioactive
Explain why ethanol is used as a biofuel
Biofuel is any fuel obtained from living or recent organisms, ethanol is used as biofuel because it is obtained from fermented sugar cane
What is a biofuel?
Any fuel taken from living or recently living organisms
Advantages of using biofuels as sources of electricity
- Biofuels are renewable sources
- Biofuels are carbon-neutral
How are biofuels carbon-neutral?
In theory, the carbon dioxide that the living organism takes in from the atmosphere balances out the amount that is released when the biofuel is burnt
Examples of biofuels
Methane and ethanol
Describe what happens inside a power station
- In coal or oil-fired power stations, and in most gas-fired power stations, the burning fuel heats water in a boiler
- This produces steam
- The steam drives a turbine that turns an electric generator
What is used as fuel in a nuclear power station?
Uranium or plutonium
Give one advantage and disadvantage of an oil-fired power station compared with a nuclear power station
Advantage - no radioactive waste
Disadvantage - produces greenhouse gases such as carbon dioxide
Give one advantage and disadvantage of a gas-fired power station compared with a coal-fired power station
Advantage - starts quicker
Disadvantage - gas supplies will run out before coal
Describe how wind power is used to generate electricity
- A wind turbine is an electricity generator at the top of a narrow tower
- The force of the wind drives the turbine’s blades around
- This turns a generator
- The power generated increases as the wind speed increases
Disadvantage of wind power
Unreliable because when there is little or no wind the wind turbines cannot generate any electricity
Describe how wave power is used to generate electricity
- A wave generator uses the waves to make a floating generator move up and down
- This motion turns the generator so it generates electricity
- A cable between the generator and the shoreline delivers the electricity to the grid system
Disadvantages of using wave power to generate electricity
- Unreliable, they don’t produce a constant supply of electricity
- Lots of cables and buildings are needed along the coast to connect the wave generators to the electricity grid, this can spoil areas of coastline
Which type of fossil fuel power station has the shortest start-up time?
Gas
Advantages of nuclear power
- No greenhouse gases
- Much more energy is transferred from each kilogram of uranium (or plutonium) fuel than from fossil fuel
Disadvantages of nuclear power
- Used fuel rods contain radioactive waste, which has to be stored safely for centuries
- An explosion in a reactor could release radioactive material over a wider area, this would affect this area, and the people living there, for many years
Advantages of renewable energy sources
- They will never run out because they are always being replenished by natural processes
- They do not produce greenhouse gases or acid rain
- They do not create radioactive waste products
- They can be used where connection to the National Grid is uneconomical
Disadvantages of renewable energy sources
- Renewable energy sources are not currently able to meet the world demand
- Wind turbines create a whining noise that can upset people nearby, and some people consider them unsightly
- Solar cells need to cover large areas to generate large amounts of power
- Tidal barrages affect river estuaries and the habitats of creatures and plants there
- Some renewable energy sources are unreliable and are not available all the time
