P1.4 Methods we use to generate electricity Flashcards
What are some energy resources that are used in a power station?
1) Fossil fuels (coal, oil, gas)- burnt to heat water or air
2) Radioactive materials (uranium, plutonium)- energy from nuclear fission is used to heat water
3) Biofuels- burnt to heat water
Describe the start up times of the different substances used to make electricity in a power station
Nuclear- longest start up time
Natural gas- shortest start up time
Describe wave power and its advantages and disadvantages
As waves come to shore, they provide an up and down motion which can be used to drive a turbine.
- No pollution, no fuel costs, provides useful energy for small islands
- Spoils view, hazard to boats, unreliable as waves die out when wind drops
Describe hydroelectricity and its advantages and disadvantages
Usually requires flooding a valley by opening a dam. Water is allowed through turbines.
- Provides an immediate response to an increased demand in electricity, minimal running costs
- Big impact on environment- flooding causes loss of habitat, unreliable if there is a drought
Describe wind power and its advantages and disadvantages
Each wind turbine has its own generator inside. Electricity is generated directly from the wind turning the blades which turn the generator.
- No pollution, no permanent damage if they are removed
- Noisy, unreliable, spoil view
Describe solar cells and their advantages and disadvantages
Generate electric currents directly from sun light. Often used to power road signs and satellites.
- No pollution, low running costs
- Only reliable in sunny countries, initial costs are high, expensive to connect to national grid
Describe geothermal energy and its advantages and disadvantages
In volcanic areas steam + hot water rise from the ground. Steam is used to drive a generator.
- No environmental problems
- Not many suitable locations, cost of building a power plant is high compared to amount of energy you get from it.
Describe tidal power and its advantages and disadvantages
Tidal barrages are big dams built across river estuaries with turbines in them. As the tide comes in it drives the turbines. The water is allowed back through the turbines at controlled speeds.
- No pollution, reliable, excellent for periods of peak demand
- Prevents free access by boats, spoils view, alters habitat of wildlife
Describe pumped storage and its advantages and disadvantages
Water is pumped into a high reservoir. This is released quickly through turbines in times of peak demand.
- Good way of storing energy, can meet high demand
- Noisy, initial costs are high
Describe carbon capture (CCS)
To prevent carbo dioxide building up in the atmosphere we can catch it then store it in empty oil and gas fields like those under the north sea
It is a rapidly evolving technology
What are some disadvantages of using biofuels to make electricity?
- Leads to deforestation
- there is a limited amount of farmland that can be dedicated to their production.
What is the order of essential parts to the national grid?
Power station- step up transformer- pylons- step down transformer- consumer
What is the role of a step up transformer?
Increases the voltage, decrease the current which reduces the energy lost as heat through the cables.
What is the role of step down transformers?
Decreases the voltage to safe useable levels and increases the current
What are the 2 ways electricity can be transfered around the country?
- over head power lines
- underground cables
What are the advantages and disadvantages of overhead power lines?
higher maintenance, ugly, effected by weather, less reliable
lower set up costs, easy to access, easy to set up, minimal disturbance to land
What are the advantages and disadvantages of underground cables?
higher set up costs, harder to access, hard to set up, disturbance to land
minimal maintenance, hidden, not affected by weather, reliable
How can supply of electricity be increased?
opening more power plants and increasing their power output
How can the demand for electricity be reduced?
encouraging consumers to use more energy efficient appliances and being more careful not to waste electricity in their homes.
How is electricity made in a power station?
energy source is used to heat water. Steam produced drives a turbine that is coupled with an electrical generator.
What are some environmental advantages of burning wood to heat a home rather than using electricity generated from fossil fuels?
wood is renewable
using wood conserves fossil fuels
wood is carbon neutral
give some environmental advantages of turning off electrical appliances when they are not being used
conserves fossil fuels
less pollutant gas is produced
Name the process by which nuclear fuel provides the energy needed to generate electricity in a nuclear power station
nuclear fission
Explain how the National Grid system reduces the amount of energy lost as heat
Step up transformers increase the current and so decrease the current
the smaller the current the smaller the energy lost
What can gas be used to do because it has a short start up time?
It can be switched on quickly so can be used to meet surges in demand
What are some ethical complications of using energy resources to generate electricity within developed countries?
- unequal use of energy resources
- should be fair access for everyone
- Consequences for he future of decisions made now
- Damage to global environment affects everyone, including people in developing countries who do not use electricity
What is meant by a reliable way of generating electricity?
The source does not rely on uncontrollable factors
Can generate all the time
What does it mean to decommission a nuclear power station?
Remove radioactive waste
How can companies generate electricity and reduce carbon emissions?
Reduce the use of fossil fuelled power stations
use more nuclear power
use more renewable energy sources
Make power stations more efficient
Carbon capture
What does the waste energy from a power station have on the surroundings?
it warms the surroundings
What is the National grid?
a system of cables and transformers
If energy produced in a power station is used locally and so is not transmitted through the national grid, why is the efficiency increased?
as less energy is wasted
this is because energy is lost as heat when transmitted through cables
What is the importance of the short start up time in power stations
can be used to meet surges in demand
suggest why using wind turbines may cause fluctuations in the electricity supply
turbines do not generate at a constant rate and wind fluctuates and is unreliable
Suggest why the amount of electricity used for lighting in homes has decreased
due to energy efficient lighting
increased energy cost so people are more likely to turn lights off
more people are becoming environmentally aware
Explain an environmental advantage of taking methane gas from coal mines and using it to generate electricity
less methane goes into the atmosphere
therefore makes global warming less rapid
Give examples to explain why electricity is essential for both improving public health and for modern communications
many devices transform electricity into other useful forms of energy
eg refrigeration of vaccines
eg telephones
Why are non renewable power stations often more reliable than non renewable power stations?
as fuel is always available for non renewable power stations
but most renewable energy sources are unpredictable so are not reliable
Give advantages and disadvantages of using nuclear power station than gas fired station
produces no carbon dioxide, longer operating life
produces radioactive waste, longer start up time
why do wind turbines not operate at a high out put all the time?
as wind is unreliable
Describe how energy is generated in a hydroelectric powerstation and the useful energy transfers that take place
water moves from a high level to a lower level
transferring gravitational potential energy to kinetic energy
rotating a turbine to turn a generator
transferring kinetic energy to electrical energy
