P1.2 Electrical energy and energy resources Flashcards
What is power
The rate of doing work - how much work is done per second
What is the equation that links power, energy transferred and time?
Power = Energy transferred / time
What is the equation that links power, work done and time?
Power = work done / time
What are renewable energy resources
Renewable energy resources won’t run out - they can be reused or replenished
What are non-renewable energy resources
Non-renewable energy resources will run out one day
List the non-renewable energy resources
coal, oil, gas and nuclear
List the renewable energy resources
solar, waves, bio-fuels, geothermal, wind, hydro-electricity and tides
What are advantages/disadvantages of fossil fuels (coal, oil and gas)?
+ Reliable
- Carbon dioxide when burnt
What are advantages/disadvantage of nuclear power?
+ Reliable
+ No green house gasses released
+ Large amount of energy per kg
- Nuclear waste is dangerous and difficult to get rid of
- Risk of nuclear accident e.g. like Fukushima
What are advantages/disadvantages of solar power?
+ Cheap once set up
+ No pollution once set up
- Not reliable - not always sunny
- Can’t increase power output to meet demand
What are the advantages/disadvantages of wave power?
+ No pollution once set up
- Destroy habitats of animals on the seabed
- Fairly unreliable as waves die down when the wind drops
What are bio-fuels?
Bio-fuels are fuels created from plant products or animal dung - they can be burnt to produce electricity
What are the advantages/disadvantages of bio-fuels?
+ carbon neutral
+ Crops can be grown all year
- They produce carbon dioxide when burnt
- Large areas of forest can be cleared to grow biofuels
What is geothermal energy?
Uses energy from hot rocks below the earth’s surface to heat water.
What are the advantages/disadvantages of geothermal energy?
+ Very reliable, hot rocks are always hot
+ Energy free once built
- Not available everywhere in the world
What are the advantages/disadvantages of wind energy?
+ Produces no carbon dioxide
+ Once built energy free
- Unreliable - not always windy
- Ugly/noisy
What is hydro-electric power?
A dam is built, the water is allowed to flow out through turbines generating electricity.
What are the advantages/disadvantages of hydro-electric power?
+ It can be used to provide electricity when there is extra demand
+ Reliable
- Destroys habitats when the dam is built.
What are the advantages/disadvantages of tidal power?
+ Tides are reliable and predictable
- Barrages destroy habitats
- Fish are killed when they swim through them
What is the national grid?
A network of cables and transformers that covers the UK
What do step up transformers do?
Increase the P.D. from power stations, reduce current which reduces energy loss from the wires heating up.
What do step down transformers do?
Decrease P.D. back down to safe levels
