1. Alternative energy sources
P3III
Alternative energy sources

2. Learning outcomes....
understand that nuclear fuel can be used in nuclear power stations
explain that nuclear power stations produce waste that is highly radioactive
understand that radioactive waste emits ionising radiation
explain that contamination by radioactive material is more dangerous than a short period of irradiation from that material

3. Nuclear power Solid fuel –e.g. Uranium
Uranium atoms split into smaller atoms, gives off large amounts of heat
1g Uranium = 8 kg fossil fuel

5. 6 mark q This question is about global warming and ozone
Many people get confused between the greenhouse effect and holes in the ozone layer
Explain the difference between the two and the scientific processes involved in each

6. 6 mark q
One way of supplying electricity to the country is with nuclear power stations
Some people are very concerned about the risk to the public from the waste produced in these power stations, while other people think the risk is low
The government will have to make decisions on this, but these decisions may be controversial
Explain why people have different views on the risk from nuclear waste, and why any decision made by the government may be controversial

7. Flow diagram
Generator converts kinetic energy of turbine into electrical energy
Energy is released from the nuclear reactor by nuclear fission
Heat energy from fission heats water to make steam
Steam turns a turbine

8. Nuclear power – advantages and disadvantages
No CO2 emissions
Much more energy given off than with fossil fuel
Relatively cheap
But....left with solid waste
Mixed with concrete and buried but radioactive for years to come
Need extra safety precautions when disposing of waste
Must check area for contamination of surrounding soil/water
People who live nearby are often scared of the risks
Takes the longest of all power stations to set up and the plant has to be decommissioned when it shuts down.
This means it takes years for the risk of radiation to leave the area and therefore the plant cannot be built on for many years

9. Radiation risk Exposure can damage cells and cause cancer – low dose
Exposure can kill cells and cause radiation sickness – high doses
The more you’re exposed to the radiation the greater the damage to cells
Workers need to be checked regularly for their background radiation levels

10. Irradiation vs contamination
Exposed to radiation without being in contact with the source of radiation
As soon as you leave area the damage stops
Only exposed for a short period so less damage
Contamination:
Absorb radioactive material e.g. Breathe it in , consume it, getting on your skin
Still exposed to radiation even after you have left area
You are exposed to the radiation for longer so it does more damage

11. Risk of contamination with radiation worse than being exposed/irradiated with radiation – why?
Long term health risks as you are affected by the radiation for longer than short term radiation (diagram)

14. Alternative energy resources
L.O explain the advantages and disadvantages of renewable energy

15. Radiation
Which exposure to radiation is worse, contamination or irradiation? Explain why. (2 marks)

16. Generating electricity

17. Electromagnetic induction
What will happen if you move a magnet into a coil of wire?
A potential difference/current is induced in the coil.
Only when the magnet is moving.

18. Stationery magnet
What happens when the magnet is stationary in the coil?
Nothing!!
A potential difference/current is only induced when the magnet is moving.

19. Electromagnetic induction
What will happen if you move the magnet out of the coil of wire?
A potential difference/current is induced in the coil.
This time in the opposite direction.
If you reverse the direction of the movement, then you reverse the direction of the current.

20. Increasing the size of the P.D/current
How can you increase the size of the current?
More turns on coils
stronger magnetic field
Increase speed of rotation
Iron core in coil of wire

22. National grid

23. National grid
Network of pylons and cables that deliver electricity to homes
Electricity can be generated far away and still reach our homes
Electricity travels at very high voltages – why?
Minimise loss of energy through heat

24. Alternative energy resources
Renewable
Less damage to the environment
No CO2 released in most cases
Unreliable
Expensive to set up/initial costs high
Ruins landscapes
Less energy than non-renewable
All contribute some pollution in building costs

25. Alternative 1 – wind power
Wind turbines set up in exposed areas, coast/open areas (to get maximum wind)
The turning of the turbine blades turns a generator inside, much like a traditional power station....but no steam needed
No pollution
Very little energy released – nearly 2000 turbines needed to produce the equivalent energy as one fuel powered station
Noisy
Don’t work when there is no wind
Cannot increase supply if there is an extra demand (e.g. During certain time of day)

27. Alternative 2 – solar power
Solar power generates electricity direct from light
Expensive to set up
Used in watches, calculators etc.
Useful in sunny countries. Can be used in remote areas not fed by the main electricity supply
Not useful in cloudy countries and useless at night
Not connected to national grid (expansive cost)– so supply local areas only

29. Alternative 3 – wave power
Uses waves along the coast
As the wave hits the shore it has an up and down motion
That kinetic motion turns a turbine that drives a generator
Spoils view and hazardous to boats
Unreliable when wind drops
Cannot use large scale but would power a small area
Need wind to produce waves

31. Alternative 4 – tidal power
Big dams are built across river estuaries
Estuaries are at the mouth of the river, where the river goes out to sea
Within the dam – called a tidal barrage – are turbines
As the tide comes in the estuary height raises several metres
This movement of water upwards turns the turbines
The water then flows out through the turbines at a controlled speed
Energy comes from the gravity of the sun and the moon
Reliable as tides occur twice a day

33. Alternative 5 – biofuel
Plants and waste material (solid material, liquid (ethanol), gas (methane)
Burnt to heat water
Used in cars
Carbon neutral – only add carbon that was recently taken out of the atmosphere while the plant was alive
Lose land that could grow crops
Lose biodiversity/habitat to grow biofuel
Increases methane emissions

34. Alternative 6 – geothermal
Hot rocks in crust
Water is pumped down and returns as steam
Drives a turbine
Cost of drilling
Very few places on earth

36. Alternative 7 – hydroelectricity
Dams that catch rain
High up, dam releases water
Moves downwards – kinetic energy – moves turbines
Floods the valley below
Flooding causes vegetation to rot
Loss of habitat
Can respond to an immediate increase in demand and reliable (drought)

38. Comparing energy resources
High demand for electricity
Need a reliable, environmentally friendly and efficient source of generating a large amount of electricity
Fossil fuels will run out, currently import fuels so costs more money
Must consider impact of alternative resources
Renewable are cheap and won’t run out, but unreliable

39. Economic impact
Setup costs – expensive for renewable power stations as they need large stations, compared to fossil fuel stations
Complexity of power station – nuclear, geothermal and hydroelectric need lots of engineering work done, which is costly
Running costs – renewable have low running costs as no fuel involved

40. Environmental impact
Fuel (fossil and nuclear) – waste pollution, CO2 emissions, (not nuclear) using resources
Visual pollution – most cause this
Using resources – fossil and nuclear
Noise pollution – fuel and wind
Destroys habitats – hydroelectric, tidal, biofuel

41. Finally...
We will need a mix of energy resources to sustain our energy demands
Must also consider the power output of the energy resource compared to the lifetime of the power station
Some may provide lots of energy but the cost to generate the energy may be high and if the lifetime of the power station is low it will not be economically viable

42. List the drawbacks of each renewable resource.
Solar needs a large area of solar panel to generate enough energy; variable output; panels expensive to make.
Hydroelectric power: means flooding large areas of countryside for reservoir; power station is remote from towns and cities, power lines needed.
Wind energy would need many wind turbines which many people dislike; spoil landscapes.
Tidal power affects the tidal flow in an estuary and will affect habitats.
Wave-power machines need to be placed at sea with the associated engineering issues.
Biomass takes up land space that could be used to grow food; may reduce biodiversity.
geothermal: only certain places this can be used and expensive to drill