1. Energy

2. Menu Non- Renewable Energy Renewable Energy Wind Hydro-electric
Biogas & Biomass
Tidal
Solar
Geothermal
Summary of Renewables
Nuclear Energy
AC and DC
Transformers
Power Stations
National Grid

3. Non- Renewable Sources of Energy

4. Non- Renewable Energy
Coal, Oil & Natural Gas are called Fossil Fuels as they are made from the remains of animals & plants that lived millions of years ago. They are very concentrated sources of energy. Oil is an especially useful material as it is the raw material for plastics, petrol & diesel.

5. Advantages of Non- Renewable Energy sources (Coal, Oil, Natural Gas & Nuclear)
Reliable
Very concentrated sources of energy
Can be used flexibly to meet
fluctuating demand
Relatively cheap & easy to find

6. What are the problems with Non- Renewable Energy Resources?
Supplies are limited. When the fuels burn, their waste gases pollute the atmosphere and cause acid rain. Another serious concern is the release of carbon dioxide that contributes to global warming
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7. Renewable Sources of Energy

8. What are the disadvantages of these renewable forms of energy?
Energy Source
Disadvantages
Wind
Wave
Tidal
Hydroelectric

9. Energy Disadvantages Source Wind Wave Tidal Hydroelectric
Dependent on weather, eye sore, difficult to store energy
Wave
Can harm wildlife, dependent on weather & size of waves
Tidal
Can interfere with shipping lanes. Has a serious impact on wildlife. Requires a lot of maintenance
Hydroelectric
Large impact on habitats. Only useful as a short term supply
All sources all have high setting up costs – particularly Tidal & Hydroelectric

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11. Wind Energy

12. How do we get energy from the wind?
This involves putting lots of windmills (wind turbines) up in exposed places like on the moors or coasts.
Each wind turbine has its own generator to make electricity directly

13. This would require a large land area.
You would need about 5000 wind turbines to make the same electricity as a coal fired power station.
This would require a large land area.
The view would be spoiled and power wouldn’t be produced when it wasn’t windy.
Initial costs are high BUT there are no fuel costs and minimal running costs.
No Pollution!
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14. Hydro-electric Energy

15. Water falling from a high level at a fast speed has a lot of energy
If the moving water can be forced through turbines, the turbines can be moved to drive generators and make electricity

16. What is a pumped storage power station?
Water is held in the higher dam and allowed to flow through turbines to make electricity when the ‘plug is pulled’. The water in the lower reservoir is pumped back up to be used again when necessary
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17. Biogas & Biomass

18. Pigs & other animals make a lot of waste
In the form of manure!
What can be done with all of this pooh?
Put it in a biogas digester and make methane gas that you can cook with!

19. What is a Biogas Digester
Rotting animal & plant waste can give off methane gas. This is similar to natural gas and can be used as a fuel

20. Biomass
Wood is an important fuel in many countries. When wood is burned, it releases energy that the tree once took in from the Sun

21. The trees that are planted are fast growing.
Unlike burning fossil fuels, wood burning does not cause a problem with the Greenhouse Effect because any CO2 released in the burning of the wood was removed when the trees grew in the first place.
Because the trees are grown as quickly as they are burnt they will never run out

22. The forest can also be used as a leisure facility before the wood is harvested.
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23. Tidal Energy

24. What is Tidal Energy?
The source of energy is the Gravity of the Sun and the Moon.
As the Earth rotates the force of gravity causes the water to ‘bulge’ – this is the ‘tide’.
Tides are reliable – they happen twice a day and we can even predict the height of each tide.

25. What is a water turbine?
When the tide moves through the turbine it spins and generates ‘clean’ energy. The energy is reliable.
The turbines produce electricity when the tides move both ‘IN’ and ‘OUT’

26. Tidal power
To gain enough energy we would need lots of underwater turbines. This would affect the movement of shipping lanes

27. The second best place in the world to get tidal energy is in the Severn Estuary
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28. Solar Energy

29. What is a SOLAR FURNACE?
The Sun’s thermal radiation energy is reflected (and focussed) towards a ‘boiler’. The water heats up & changes state to steam. The steam has a large amount of kinetic energy which turns a turbine. Electricity is then generated by a generator.

30. This is a solar power station using solar cells
Solar energy is very clean and cheap (although initially they may be expensive to set up).
It is a very reliable form of energy in sunny countries – BUT only in the daytime!
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31. Geothermal Energy

32. What is Geothermal Energy?
This is Heat from Underground.
It is only possible in some areas of the world where hot rocks lie quite near the surface.
The source of much of the heat is the slow decay of various radioactive elements including Uranium

33. How do we make electricity from Geothermal Energy?
Steam
Water
Water is pumped down and heated by the hot rocks where it turns to steam. The steam rises because it is less dense and turns a turbine, which drives a generator to make electricity
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34. Summary of Renewable Sources of Energy

35. Complete the table on the next slide
For each source of energy give:-
A description of how it is used
2 advantages
2 disadvantages
Try not to say the same thing more than once!

36. Energy Source Tidal Energy Solar Energy Biomass Energy Wind Energy
Description of Energy Source
2 Advantages of using Source
2 Disadvantages of using Source
Hydroelectric Energy
Tidal Energy
Solar Energy
Biomass Energy
Wind Energy

37. Renewable sources of energy are cheaper, cleaner and will not run out
Renewable sources of energy are cheaper, cleaner and will not run out. However, they are incapable of providing all the energy we need, so we will have to go on burning fossil fuels for now.
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38. Nuclear Energy

39. Nuclear Energy
This is uranium. A small amount of fuel produces a vast amount of energy. It also produces lots of radioactive waste!
In a reactor, nuclear reactions release energy from the nuclei of uranium atoms. This heats water to make steam for driving generators

40. The Splitting up of Atoms Is Called Nuclear Fission
Nuclear power stations and nuclear submarines are both powered by nuclear reactors
In a nuclear reactor,a controlled chain reaction takes place in which uranium atoms split up and release energy in the form of heat. This turns water to steam to drive a turbine & generate electricity

41. Nuclear Processes Release More Energy Than Chemical Processes
When a nucleus splits it gives out a lot more energy than a chemical bond. This is why nuclear bombs release a lot more energy than other bombs

42. Power Stations

43. What is a power station?
Power Stations are places where electrical energy is made. Electrical Energy is a convenient form of energy to use in our homes.

44. Fossil Fuel Power Stations can generate a lot of pollution
In the form of carbon dioxide, sulphur dioxide and smoke

45. The sulphur dioxide can lead to the production of acid rain
And whole forests
It can damage leaves
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46. The National Grid

47. What is the National Grid?
When electricity is generated in the power station it is transported to us by the National Grid
It is a network of pylons and cables that covers the whole country

48. Step-down Transformer
The National Grid
Power Station
25,000V
Step-down Transformer
Homes
Step-up Transformer
400,000V
230V
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49. AC & DC

50. Alternating Current (AC)
Voltage
The current changes direction 50 times every second (frequency = 50Hz)
Time
AC is easier to generate than DC

51. If the cell is reversed the current flows in the opposite direction
Direct Current (DC)
The current only flows in one direction
Voltage
Time
If the cell is reversed the current flows in the opposite direction
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52. Transformers

53. Transformers Transformers transform (change) the Voltage
Transformers only work on AC because there is constantly changing flux

54. Step Up & Step Down Primary Coil Secondary Coil Primary Coil
Step Up Transformer
More turns on the Secondary Coil
Step Down Transformer
More turns on the Primary Coil

55. Some Transformers Look Like This…..
…..you might have heard their characteristic ‘hum’

56. The Transformer Equation
Primary voltage = Number of turns on Primary
Secondary voltage Number of turns on Secondary
The ratio of the turns on the coils equals the ratio of their voltages

57. No. of Turns on Secondary
Complete the table
Primary Voltage
Secondary Voltage
No. of Turns on Primary
No. of Turns on Secondary
Step Up or Step Down?
12V
36V
100 ?
600V
300V 20
20,000V
50,000V
1,000
23V
230V
150

58. Why Do We Step Up the Voltage?
Transmission cables can be hundreds of kilometres long. This means that energy is wasted because of the heating effect of the current.
By using a transformer to increase the voltage, the current is reduced, so thinner, lighter & cheaper cables can be used

59. Resistance & Power Loss
When a current flows through a conductor it has a heating effect so power is wasted. The power loss can be calculated like this……
Power Loss = Current2 X Resistance
Power Loss is reduced significantly if the current is reduced
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