P1 Revision 6

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  • Created by: LBC0502
  • Created on: 14-06-14 13:43
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  • P1 Revision
    • Biomass and Fuels
      • Advantages: Uses products which might otherwise be wated, so fuel costs are very low. Power stations can also supply hot water to local industry/homes. Carbon neutral (burning fuel doesn't cause a net increase in the atmosphere.
      • Plants absorb carbon dioxide which is harvested and processed to be converted into ethanol which is an alcohol/fuel. Bio fuels are made from living things or waste organisms produce e.g. wood, wood chippings, straw, pellets or liquids made from wood, biogas (methane) from animals excrement. Ethanol, diesel or other liquid fuels made from processing plants or waste oil (cooking oil - restaurants/chip shops). Ethanol/ diesel made form crops (e.g. corn).
      • Disadvantages: Releases atmosphere pollutants. In developing countries, land which could be used for food is now used to grow crops for bio fuels, leading to food shortages. Power plants can be ugly to look at.
      • A fuel is a substance burnt to produce energy. Biofuels are renewable because they can be re-produced and cabron dioxide is absorbed by the plant. Biomass is a renewable energy source and there are lots of types of biomass but they all involve materials produced by living organisms. Biomass if one of the bio fuels (carbon neutral).
    • Renewable Resources
      • Hydroelectric Power (Used in mountainous regions where they allow the formation of deep reservoirs and used in locations with large powerful rivers and steep side valleys. Kinetic/Potential energy used): (A) No fuel required, no polluting gases. Fast start up time. Produces large amounts of clean electricity. Stores energy. Water can be pumped back up to the reservoir when demand for electricity is low. Supplies high demand (pump storage system). (D) Location is critical. Involves damming upland valleys (flood farms/destroys local ecosystems). Need adequate rainfall to achieve net output. Alters natural water table level. Expensive to build.
      • Solar Power (Used where small amounts of energy are required and are used in remote locations to power road signs. Light energy from solar cells used): (A) Renewable energy. No fuel costs. No polluting gases produced. Good energy source for small amounts. Produces clean electricity. Charges batteries. (D) Solar cells are expensive. Inefficient. Requires lots of panels. Not aesthetically pleasing. Cost of electricity is high. Don't work at night. Dependent on light intensity.
      • Geothermal Power (Used in locations with high tectonic activity. Used in Iceland which is a volcanically active region. Uses thermal energy/radioactivity): (A) No fuel costs. No polluting gases produced. Renewable. Built close to community. Clean source of energy. Sustainable. Not dependent on weather. (D) Available in limited locations. Expensive to construct. Danger of eruption of volcanoes. Produces low amounts of electricity.
      • Wind Power (Can be used almost everywhere and people who live in locations where there is lots of wind can produce lots of electricity. Kinetic energy is used): (A) No fuel required. Renewable source. Little maintenance required. No polluting gases produced. Provides free energy. Built off-shore. Wind capture efficiently. (D) Requires lots of turbines. Noisy. Not aesthetically pleasing. Strength of wind varies. Expensive to build. Doesn't meet demand.
      • Tidal Power (Not yet widely used. Used in locations near oceans and seas, estuaries/large tidal change. Uses kinetic/potential energy): (A) No fuel required. Not polluting gases produced. Produces free reliable energy. Barrage water can be released when demand is high. Tides are predictable. Low operating costs. Renewable. (D) Destroys habitats of wading birds (water kept behind barrage keep high level of water, not releasing mudflats). Visual pollution. Hazard to shipping. Variations of tidal wave. Limited supply of energy.
      • Fossil Fuels (Can be used almost everywhere. Chemical energy is used): (A) Provides a continuous supply of electricity. Provides lots of energy so can make lots of electricity. (D) Produces large amounts of carbon dioxide. Fossil fuels will run out.
    • Nuclear Power
      • Disadvantages: Produces highly radioactive nuclear waste, remains dangerous for millions of years, needs to be buried underground. The cost of building the plant/taking it down when finished (decommissiong) is quite high (electricity generated can be expensive). Nuclear reactors have a slow start up time. It takes a long time to increase or decrease the amount of electricity they are generating.
      • 13% of electricity in UK comes from nuclear power and there are plans to build several more power stations. 1kg uranium = 15,000kg of coal (concentrated energy source). Uranium is a non-renewable resource/not infinite.
      • Nuclear fuel is used to generate electricity and doesn't burn. Reactions in uranium take place that split atoms and release large amounts of energy (heat). This process is called nuclear fission. Nuclear reactor - Heat water - Create steam - Turn a turbine - Turn generator - Electricity.
      • Used fuel contains some uranium which can be separated from waste, also contains plutonium (highly radioactive, used in construction of nuclear bombs).
      • Nuclear waste: comes from nuclear power stations, hospitals/research laboratories, needs to be disposed where there is not health hazard (depending on level of radioactivity.
      • Advantages: Huge amounts of electricity generated for each kilogram of fuel. No carbon-dioxide produced so there is no contribution to global warming. Fuel is not going to run out for thousands of years and is readily available.
      • Intermediate level waste: radioactive waste is put into durms and are casted in concrete and buried under 8m of clay or drums are buried deep underground in disused mines.
      • Dangers of radioactivity: large doses burn skin, delayed effects, damage to bones, blood exposure to low dose results to leukaemia/cancer, radioactive elements irradiate organs, emit a-rays, damage human genes (birth of deformed babies).
      • Low level waste: power stations produce radioactive cooling water, passes through long pipes to sea, discharged 1-2km from shore, laboratory equipment/protective clothing placed in metal containers which are buried, soil cover replaced/replanted.
      • Nuclear Power: fuel of uranium/plutonium, control rods/moderators slow down reaction (absorb) neutrons, closed system with thick concrete, hot/heated water used to turn water in the exchanger into steam, steam is sent to turbine,cold water is passed through the heat exchanger and closed system.
      • High level waste: highly radioactive fuel rods are stored in cooling ponds of water (until they are less radioactive) then moved to a special treatment plant where the rods are dissolved in acid then stored/cooled until it is less radioactive. Liquid waste is vitrified (turned into glass
      • First power station built in Finland. Coast cleared for nuclear power station (a way of importing gas). Nuclear power stations produce radioactive waste which needs to be stored (60-500 metres underground). Families would move away from nuclear power station areas.
    • Carbon Capture
      • Instead of being released into the atmosphere, carbon dioxide is captured  at power stations and is compressed. The compressed carbon dioxide is pumped through a network of pipelines, some new and some formerly used for natural gas to a suitable well previously used for gas extraction.
      • Disadvantages: Carbon capture uses between 10% - 40% of the energy of the power station. The safety of the carbon storage is not guaranteed. Leakage may damage the climate. Carbon capture is very expensive and the money spent on it could be spent on solutions for other climates.
      • Carbon is present in: all fuels, living things, hydrocarbons and carbon-dioxide. Coal - Very high carbon dioxide production. Oil - High carbon dioxide production. Natural Gas - Medium carbon dioxide production.
      • Advantages: Could reduce over 80% of amount of carbon dioxide entering the atmosphere from a coal power plant. Allows the continued use of low cost fossil fuel energy sources.
      • The carbon dioxide is pumped down through the well into porous rocks which previously held gas deep beneath the sea bed. The carbon dioxide filters into the porous sandstone reservoir, filling the tiny spaces which once held natural gas. It is trapped from escaping by the layers of solid rock above, just as the was trapped for millions of years.

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