Energy Resources Flashcards
How do power stations work?
In coal or oil fired power stations and in most gas fires power stations, the burning fuel heats water in a boiler. This produces steam which drives a turbine that turns an electricity generator.
What are biofuels?
Any fuel taken from living or recently living organisms. E.g. animal waste, methane, decaying rubbish and ethanol.
What is biodiesel?
Uses waste vegetable oil and plants such as rapeseed.
Positives of biofuel?
Renewable Carbon neutral. Cheaper Employs workers Produced from a wide variety of plants Lower co2 emissions
What is nuclear power?
Nuclear fuel takes energy from atoms. The fuel is uranium. The nucleus of a uranium atom is unstable and can split in two. When this happens, energy is transferred from the nucleus. As there are lots of these atoms in the core, it becomes very hot. The uranium is sealed in cans in the core of the reactor.
How is the energy transferred in nuclear power.
Transferred by a fluid (coolant) that is pumped through the core.
- the coolant is very hot when it leaves the core. It flows through a pipe to a heat exchanger, then back to the reactor core.
- the energy transferred by the coolant is used to turn water into steam in the heat exchanger. The steam drives a turbine that turns electricity generators.
Which produces more energy, nucleus or fossil fuel?
Nucleus is 300 000 MJ
Fossil Fuels are 30 MJ
What are the cons of biofuel?
Lots are needed to produce the same amount of energy as fossil fuels.
Rainforests are cut down to grow pal oil trees.
What is wind power?
The force of the wind drives the turbine’s blades around. This turns a generator.
Disadvantages of wind power?
Unreliable
Ruins the view
Noisey
5000 turbines needed to generate the same amount of energy as a power station.
Advantages of wind power?
Used anywhere
No air pollution
Little environmental impact.
What is tidal power?
Traps the water from each high tide behind a barrage. The high tide can the be released into the sea through turbines. The turbines drive generators in the barrage.
Advantages of tidal power?
Reliable
Predicable
No pollution
Disadvantages of tidal power?
Not constant
Restricts shipping
Restricts the flow of water
Built across a river estuary so can affect habitats such as mud flats and salt flats.
What is wave energy?
Wave generators uses waves to make floating generators move up and down. This motion turns the generators electricity. A cable between the generator and the shoreline delivers electricity to a grid system. (Pushed air through the turbine).
Disadvantages of wave energy?
Spoils coastline
Tidal flow may change, affecting habitats.
Hazard to boats.
Advantages of wave energy?
Constant supply.
What is hydroelectricity?
When rainwater that is collected in a reservoir flows downhill. The flowing water drives a turbine that turns a generator at the bottom of the hill.
Advantages of hydroelectric?
No pollution
20% of the world’s electricity
Reliable-always flow
Disadvantages of hydroelectric?
Only a few suitable sites.
Reduces the flow downstream which effects habitats there.
Usually requires the flooding of a valley-environmental damage.
Flow of river is affected downstream which damages habitats.
What is geothermal energy?
It comes from energy released by radioactive substances deep within the Earth. The energy transferred from these radioactive substances heats the surrounding rock. Energy is transferred by heating towards the Earth’s surface.
The rocks are hot due to the decay of radioactive elements deep under-ground.
Advantages of geothermal energy?
Free.
No environmental problems.
Disadvantages of geothermal energy?
Only possible where hot rocks are close to the surface because the cost of drilling is so high.
Very few geographical locations. For example, Iceland.
What is biomass?
Organic stuff that can be burnt to produce electricity. The material is burnt in a power station to heat water, produce steam and turn a turbine.
Advantages of biomass?
Set up costs are low.
The process uses waste that otherwise would be used as landfill.
The plants are carbon neutral.
Disadvantages of biomass?
Pollutants such as sulphur dioxide may be produced.
What are solar cells?
Generate an electric current directly from sunlight. There is no generator. They convert less than 10% of the solar energy they absorb into the energy transferred by electricity.
Advantages of solar cells?
Useful when small amounts are needed (watches or calculators) or remote areas (middle of the ocean).
Expensive to buy but cost nothing to run.
Disadvantages of solar cells?
Unreliable in places where the sun is often covered at night or at night.
Lots are needed.
What are solar heating panels?
They heat the water that flows through it. They can supply lots of hot water.
Problems with fossil fuels?
Non-renewable
Greenhouse gases - global warming.
Sulphur Dioxide - acid rain.
Why are fossil fuels called fossil fuels?
They are formed in the same way as fossils.
How are oil and gas formed?
When organisms died in the North Sea they were trapped in sand and mud which formed sediment. The pressure changed and the sand and mid changed to sandstone and mudstone. Pressure and heat changed then into oil and gas.
How is coal formed?
Dead trees fell into swamps and they were buried by mud which stopped them from rotting as it kept the air out. The mud continued to pile up and the trees were squashed together. The heat from the earth also affected them. They were changed into coal which is usually found deep underground covered by deep sediment.
Advantages of nuclear power?
No greenhouse gases.
Much more energy per kg of uranium.
Disadvantages of nuclear power?
Used fuel rods which contain radioactive waste, which has to be stored for centuries.
An explosion in a reactor could release radioactive material.
Advantages of renewable energy?
Never run out
No greenhouse gases
No radioactive waste
Can be used where connection to national grid is uneconomical.
Disadvantages of renewable energy?
Can’t meet the worlds demand Wind turbine - noisey Tidal barrage - environmental Solar cells- need large areas of land for enough power. Some are unreliable. Hydroelectric - environmental.
What is a TV pickup?
Is where there is a sudden increase in the demand for electricity either during a commercial break or at the end of a programme.
