Generating Electricity Flashcards
How is the water heated in power stations
By burning fossil fuels
How do most power stations work
- water is heated to produce steam
- the steam drives a turbine
- the turbine drives a generator that produces electricity
What are fossil fuels
Long- dead biological material
Why can a gas fired turbine be turned on very quickly
Because hot gases can turn the turbine directly and quickly, which turns the generator quickly
What is a biofuel
A fuel obtained from living or recently living organisms- made from animal or plant oils
Why are biofuels god to use in a gas fired power station
Because they are renewable
What fuel is used In nuclear power stations
Uranium, sometimes plutonium
What type of reaction happens in a nuclear reactor
Nuclear fission
How does a nuclear power station work
By nuclear fission, which releases energy, the energy is used to heat water, turning it into steam
Why are nuclear power stations more useful than fossil fuel stations
More energy is released per kilogram of uranium undergoing fission reactors than that from each kg of fossil fuel
Give examples of renewable energy
- geothermal
- hydroelectric
- solar
- wind
- wave and tidal
What Do we mean when we say a renewable energy source
These energy sources can never be used up
How does a wind turbine generate electricity
Wind passing over the blades makes them rotate and drive a generator at the top of a narrow tower
How does a hydroelectric power station work
Water is collected in a reservoir, this water is allowed to flow downhill and turn turbines at the bottom of a hill
Why can hydroelectric power be used at times of high demand
At times of high demand the water can be pumped to the top of a hill to the reservoir, this means energy is stored. The water can then be released and fall through the turbines and transfer stored energy into electrical
What is the stored energy in the top reservoir of a pumped storage system
Gravitation potential
How does wave power work
The movement of the waves drive a floating turbine and turns a generator, then electricity is delivered to the shore by a cable
How does tidal power work
A barrage is built across an estuary, which traps the water at each tide. When the water is released, it falls to reach the rest of the sea level and drives a turbine
Why is wave power less reliable than tidal power
Because tides happen twice a day but there are not always big waves
In what form does solar energy travel though space
Infra-red/ electromagnetic radiation
Why are there solar cells on calculators and watches
Because each solar cell only produces a small amount of energy, so they are useful to power small devices
What is a solar panel made up of
Multiple solar cells
How is water heated in a solar heating panel
There are pipes of water that go through the panel, the solar energy hits the black cover and heats the water directly
How does a solar power tower work
Thousands of mirrors direct sunlight onto a water tank to heat water and produce steam
How is geothermal energy produced
By radioactive processes in the earth, which heats the surrounding rock. Holes are drilled and cold water is fed into these holes, the water returns to the earth surface as steam. The steam drives turbines that turns generators.
Why are only a few places able to have geothermal power stations
Because in many places the hot records are too low under the surface to reach
Name four non renewable energy sources
Coal, oil, gas, uranium
What does renewable energy source mean
That the energy being produced mean is equal to/more than the amount that is being used
What are the advantages/ disadvantages of coal
Ads Bigger reserves than other fossil fuels Reliable Disads Non renewable Produces co2 (greenhouse gas) and so2 (acid rain)
What are the advantages and disadvantages of oil
Ads Reliable Disads Non renewable Produces co2 and so2
WhT are the advantages and disadvantages of gas
Ads Reliable Disads Non renewable Produces co2
What are the advantages and disadvantages of nuclear
Ads No production of pollutant gas Free energy resource Disads Non renewable Produces hadardous nuclear waste, which is difficult to dispose of Small risk of big nuclear accident
What are the ads and disads of wind power
Ads Renewable No production of pollutant gas Reliable in wet areas Free enaergy source Only works in wet hilly areas Damming and area causes flooding and damages local economy
What are the advantages and disads of wave power
Ads Renewable No pollutant gas Free energy recourse Disads Can b hazardous to boats Not reliable
What are the ads and disads of tidal power
Ads Renewable No pollutant gas Reliable Free resource Disads Only few estuaries are suitable Building. Barrage affects local ecology
What are ads and disads of solar power
Ads Renewable No pollutant gas Reliable in hot countries Disads Only produces small amount of energy Unreliable in less sunny countries
What are the ads and disads of geothermal power
Ads Renewable No pollutant gas Free Disads Only economically viable in few places Drilling through rock is difficult and expensive
What is the national grid
A network of pylons and cables that connects power stations to homes, schools, factories and other buildings
How is electricity transported from the national grid across the country
By overhead pylons
How is the electricity from the national grid transported in cities and towns
Underground cables
What are the advantages of overhead cables compared to underground cables
They are easier to fix if fault occurs
They are cheaper
Why are step up transformers used in the national grid
To increase the voltage to reduce the energy loss through cables, making the system more efficient
Why are step down transformers used
To make sure the voltage is safe to use in homes
What is the voltage of electricity used In homes
230 volts
What is the “base load” demand
The constant amount of energy that is produced from nuclear, coal fired and oil fired power stations
Why does this demand for energy vary between summer and winter
The demand increases in winter as it is colder and decreases in summer due to warmer weather
How is the variable demand met
By gas fired power stations, pumped storage stations and renewable energy sources
Which type of power station has the shortest start up time
Gas fired stations
Which type o station has the longest start up time
Nuclear power stations
