How the sun creates energy
- Solar energy from the sun is created as a result of nuclear fission in the form of heat and light.
- This energy is transferred to coal through photosynthesis and compression of biomass over time.
- The sun’s energy is transferred to wind because of the earth’s rotation on its own axis causing the atmosphere to be heated by the sun and then cooled. This creates air currents – wind.
Renewable energy resources (not finite)
- Food supplies – energy is transferred through the food chain from food supplies. This energy originates from the sun.
- Solar power – energy falling on earth from the sun is mostly light energy. It’s low energy density requires large collecting devices and its availability varies. It is most useful in countries with sunny climates.
- Hydroelectric – In the UK hydroelectric power stations generate about 2% of electricity supplies. The sun’s heat evaporates water from the sea and this water vapour falls as snow or rain on mountains. Some of this water finds its way into mountain rivers and lakes. The sun’s heat has been converted into potential energy of the water. As the water flows down into the sea, this potential energy can be converted into kinetic energy.
- Tidal – In some river estuaries there is a large difference in water level between high and low tides. This tidal flow can be used to create power if a barrage is constructed.
- Wave – There is a lot of energy in the rise and fall of sea waves.
- Wind – Energy from the wind can be put to use using wind mills and generators but wind does not produce a lot of electricity.
Non renewable energy resources (finite)
- Coal – Laid down over 300 million years ago – formed from remains of plants and animals. Burning coal produces acid rain.
- Oil – Formed in the same way as coal. Newer oil fields are in remote areas or in the sea.
- Natural gas – Formed in the same way – supplies are running out.
- Nuclear fuels – Energy locked in the nucleus of the uranium atom is released as heat. The heat is used to make steam. Like fossil fuels, causes environmental problems.
How electricity is produced using
- Solar panels – Used as energy transfer devices, converting sunlight into heat energy. Common in hot climates to heat swimming pools and produce domestic hot water.
- Pumped storage reservoirs – Engineers can dam rivers and lakes so large reservoirs of water are formed. These supplies of water can turn large water wheels (water turbines) which drive electrical generators.
- Tidal barrages – Barriers put across estuaries where the flow of water from a high to low level is used to drive a water turbine connected to a generator
- Wave machine – Difficult to convert sea wave energy by some kind of wave energy converter into the rotary motion required to drive a generator. The up and down movement of a single float inside a tower is converted into rotary motion, which drives an electrical generator.
- Wind turbines – These are giant windmills with two or three blades which drive electrical generators. They do not produce a lot of energy.
- Gas, coal and oil power stations – These are thermal power stations which produce heat energy that turns water into steam. The steam drives turbines which in turn drive generators that produce electrical energy. The steam is obtained from a boiler.
- Nuclear power stations – Steam is made from the heat released from the energy locked in the nucleus of the uranium atom. The steam is produced in a heat exchanger. Steam turbines drive electrical generators to make electrical energy.
Advantages and disadvantages of energy production by renewable resources
|Good for the environment||Expensive|
|Will not run out||Needs large input for little output – not as efficient|
|Non polluting||A blot on the landscape|
Advantages and disadvantages of energy production by non-renewable resources
|Readily available||Will run out|
|High density and relatively small size of energy transfer device makes more efficient||Nuclear fuels cause dangerous waste material|