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objectives
objectives
Energy Resources
Energy Resources
- Most of the energy that we use comes from fuels that are burned in power stations, factories, homes, and vehicles. Nearly all of this energy originally came from the Sun. To find out how, see the next lesson
- The Sun is 75% hydrogen. It releases energy by a process called nuclear fusion, in which the nuclei (centres) of hydrogen atoms are pushed together to form helium. One day, it may be possible to harness this process on Earth, but until this can be done, we shall have to manage with other resources.
Non-Renewable Energy Resources
Non-Renewable Energy Resources
- Fossil fuels Coal, oil, and natural gas are called fossil fuels because they formed from the remains of plants and tiny sea creatures which lived millions of years ago. They are a very concentrated source of energy.
- Oil is especially useful because petrol, diesel, and jet fuel can be extracted from it.
- It is also the raw material from which most plastics are made.
Natural gas is the ‘cleanest’ of the fossil fuels.
- At present, it is mostly taken from the same underground rock formations that contain oil the gas formed with the oil and became trapped above it.
- However, over the next decades, more and more gas will be extracted from a rock called shale.
Problems with Fossil Fuels
- When fossil fuels burn, their waste gases pollute the atmosphere. Probably the most serious concern is the amount of extra carbon dioxide being produced. This may he adding to global warming.
4.07---How-does-fracking-work.mp4
Nuclear fuels
- Most contain uranium. 1 kg of nuclear fuel stores as much energy as 55 tons of coal. In nuclear power stations, the energy is released by fission, a process in which the nuclei of uranium atoms are split.
Problems with Nuclear Fuels:
- High safety standards are needed. The waste from nuclear fuel is very dangerous and stays radioactive for thousands of years.
- Nuclear power stations are expensive to build, and expensive to decommission (close down and dismantle at the end of their working life).
Renewable Energy Resources
Renewable Energy Resources
Hydroelectric energy
- A river fills a lake behind a dam. Water flowing down from the lake turns generators.
Problems with Hydroelectric energy:
- Expensive to build.
- Few areas of the world are suitable.
- Flooding land and building a dam causes environmental damage.
Tidal energy
- Similar to hydroelectric energy, but a lake fills when the tide comes in and empties when it goes out.
Problems:
- As for hydroelectric energy.
Wind energy
- Generators are driven by wind turbines (windmills’).
Problems with wind Energy:
- Large, remote, windy sites are needed.
- Winds are variable.
- The wind turbines are noisy and can spoil the landscape.
Wave energy
- Generators are driven by the up-and-down motion of waves at sea.
Problems with Wave Energy
- Difficult to build - few' devices have been successful.
Geothermal energy
- Geothermal' means heat from the Earth. Water is pumped down to hot rocks deep underground and rises as steam. In areas of volcanic activity, the steam comes naturally from hot springs.
Problems with Geothermal Energy:
- Deep drilling is difficult and expensive.
Solar energy (energy radiated from the Sun)
- Solar panels absorb this energy and use it to heat water.
- Solar cells are made from materials that can deliver an electric current when they absorb the energy in light.
Problems with Solar energy
- Variable amounts of sunshine in some countries.
- Solar cells are expensive, and must be large to deliver useful amounts of power.
- A cell area of around 10 m2 is needed to power an electric kettle.
Biofuels
- These are fuels made from plant or animal matter.
- They include wood, alcohol from sugar cane, and methane gas from rotting waste.
Problems with Biofuels:
- Huge areas of land are needed to grow plants.
Conclusions on Saving Energy
Conclusions on Saving Energy
- Burning fossil fuels causes pollution.
- But the alternatives have their own environmental problems.
- That is why many people think that we should be less wasteful with energy by using vehicles more efficiently and recycling more waste materials.
- Also, better insulation in buildings would mean less need for heating in cold countries and for air conditioning in hot ones.
Energy Resources Worksheet
Energy Resources Worksheet
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