Generating Electricity

1. Generating Electricity Physics 1 GCSE Science Chapter 10

2. Oil Energy– the problem with using too much Where do we get most of our energy from? Coal Gas GCSE Science Chapter 10 Environmental problems! (Atmospheric pollution and climate change)

3. When the Earth radiates the absorbed heat energy back into space, it is in the form of infra-red radiation with a longer wavelength. Some molecules, such as carbon dioxide and methane, absorb some of this longer wavelength radiation, and trap the energy within the atmosphere. Consequently the atmosphere heats up – this is known as the Greenhouse Effect. What happens to the Earth? Earth’s Atmosphere Sunlight travels as electromagnetic waves through space and the atmosphere, towards the Earth. A proportion of this energy is absorbed, and a part of it is reflected. GCSE Science Chapter 10 Global Warming

4. The Effect of Global Warming What will the effect of a temperature rise of 2°C be? Winters will be warmer More deserts – less land to grow crops. The sea level will rise as a result of polar ice caps melting. Change in climate – more extreme weather, floods and drought becoming common. GCSE Science Chapter 10 The Gulf stream’s direction could change and as a result, Britain’s temperature would fall. Our carbon dioxide emissions is responsible for this, and there is a constant campaign to get us to burn less coal, oil and gas.

5. Oil The Energy Crisis Coal, oil and gas are examples of non-renewable resources. Coal Gas After using them once, you cannot re-use them – you would have to wait millions of years for them to be produced. By 2020 we in Britain will have to reduce our dependence on coal, oil and gas and produce electricity by renewable means. GCSE Science Chapter 10

6. boiler Coal, oil or gas Thermal Power Stations 4. Turbine turning the generator and producing electricity. 3. Steam turning the turbine 2. Cold water turned into steam in the boiler. turbine generator Hot steam Steam Cold steam steam Hot water Water Cooling tower Cold water Cold water condenser GCSE Science Chapter 10 5. Part of the energy is lost to the environment at this stage. 1. Burning Fossil Fuels It’s possible to use the waste steam to heat the factory or nearby houses. Fossil Fuel

7. Is it possible to improve the design? The latest power stations use the hot water to heat up the surrounding houses. Generator Hot steam Turbine National grid Heat Hot water Condenser It’s possible to use wood as fuel. New trees can be planted and grow quickly to replace the fuel supply. These trees absorb CO2 as they grow and release it when they burn – so no net gain or loss of CO2. GCSE Science Chapter 10 Cold Water

8. Cooler Steam generator core fuel Thermal Power Station 4. The turbine turning and generating electricity. 3. Steam turning the turbine 2. The steam generator turns cold water to steam turbine generator Hot steam Steam Cold steam steam Hot water Water Cooling tower Cold water Cold water condenser GCSE Science Chapter 10 5. At this stage, part of the energy is lost to the environment. 1. A nuclear reaction in the core. One nuclear station is equal to 2400 wind turbines! Nuclear

9. Gas Oil Coal Nuclear Fast Oil Oil Slow Start up time The different types of power stations have different ‘preparing to start’ times: GCSE Science Chapter 10

10. Low fuel costs High commissioning and decommissioning costs in a nuclear power station Good for meeting basic energy requirements Coal, oil, gas and nuclear Fuel supplies depleting Dependable Gas and oil have a low start-up time Pollution – CO2 leads to global warming and SO2 to acid rain Nuclear energy creates very little pollution Non-renewable Energy Sources Disadvantages Advantages GCSE Science Chapter 10

11. Renewable Energy – Wind Power Wind turbines are a familiar site in this country. The sites are called ‘wind farms’. Strong winds in Britain mean that this is a viable source of energy production for us. GCSE Science Chapter 10 However, some are against this . They claim that the wind turbines destroy habitats, that they are noisy and ineffective.

12. Renewable Energy – Tidal Power High Tide Low Tide GCSE Science Chapter 10 As the tides turn, the movement of the water turns the turbine, and the generator produces electricity.

13. Renewable Energy – Wave Power GCSE Science Chapter 10 The movement of the waves causes the float to move up and down. This turns the generator and it produces electricity.

14. Renewable Energy – Hydro-Electric Power and Pumped Storage High resevoir GCSE Science Chapter 10 When electrical energy is needed urgently, this hydro-electric system is used. Water form a high resevoir is released and as it flows, it turns the turbine and produces electricity. It depends on gravity. In a pumped storage scheme, an electrical pump can be used to pump the water back into the resevoir at off-peak rates, and so it can be re-used.

15. Are there disadvantages to using renewable sources? Weather-dependent; can be perceived as being an eye-sore by some; difficult to store. Can be harmful to marine life; dependent on the size of the waves; weather-dependent. Depends on the size of the tide and can affect habitats if mud flats are not uncovered for birds to feed. GCSE Science Chapter 10 Habitats suffer due to flooding of river valleys in some schemes. Also, the above have a long start-up time

16. No fuel costs Unreliable (except Hydro-electric) No pollution Expensive to build Wind, tide, hydro-electric and solar Hydro-electric good for urgent demand for electricity Tidal barriers destroy bird habitats and hydro-electric depends on flooding farm land Solar is good for remote areas (e.g. satellites) Renewable Energy Sources Disadvantages Advantages GCSE Science Chapter 10