Questions on Energy Sources
Q11. The tides can be used to generate electricity. A dam is built across a river estuary, as shown below.
(a) The water is higher on one side of the dam than on the other. As the water begins to flow through the dam it turns a turbine. The turbine generates electricity. Describe the useful energy changes which take place in this process.
- Gravitational .potential energy in the water to kinetic energy in the water
- Kinetic energy in the water to kinetic energy in the turbine
- Kinetic energy in the turbine to kinetic energy in the generator
- Kinetic energy in the generator to electrical energy
MAX 2 marks
(b) Explain why tides are classified as a renewable energy source.
Tides are classified as a renewable energy source because the Moon's gravitational pull on the oceans is always there and follows a regular pattern of pull that we can use.
1 mark
(c) Give one way, other than from the tides, of generating electricity by using the sea.
Wave power accept ‘Ocean Thermal Energy Conversion’ or ‘OTEC’
1 mark
(d) Apart from cost, give one advantage and one disadvantage of an oil-fired power station compared with a tidal power station.
Advantage
An oil fired power station's output is easier to control than a tidal power station - it can be turned on when it is needed whereas the tides only give power at certain times.
You can build an oil-fired power station anywhere nut a tidal power station can only be built in a tidal estuary.
Disadvantage
Oil is non-renewable - it therefore will run out, whereas tidal power is renewable.
Oil causes pollution when burnt and it gives out greenhouse gases. It can also can cause pollution by oil spills. Tidal power stations cause hardly any pollution in comparrison.
One mark for advantage and one for disadvantage.
2 marks
Maximum 6 marks
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