Generating Electricity

Fossil Fuels
1. Chemical energy is burned, heat turns water (gas doesn't) to steam, vapour turns turbine, kinetic energy turns magnet inside coils in generator.
2. Shortest Start up time: Gas, Oil, Coal, Nuclear: Longest Start up time
3. Ad: Large scale production, Established technology, cheap, continuous, controlled amount can be produced.
4. Dis: CO2, global warming, weather conditions, SO2, acid rain, environment, dust and ash if not cleaned, nonrenewable.
5. Nuclear
  1. A neutron collides with a uranium atom, and the U atom splits up.
    1. The heat produced turns water to steam which turns a generator producing electricity
    2. Boron rods (where the neutron is from) are lifted up and down in the reactor to control how much fission occurs.
  2. Ad: Large scale production, established tech, cheap, 10000 times more energy is released that other fossil fuels, No emission of CO2 or SO2.
  3. Dis: risk of nuclear accident, waste is dangerous and takes ages to become safe, difficult to dispose of, taking it out of use it expensive,
Wind Power
1. Wind drives a generator that produces electricity
2. Placed on tall towers on hilly sites
3. Ad: wind is free, no pollution or waste, does not take up much ground space, can be used in remote locations (at sea), cheaper to take down.
4. Dis: more wind off shore but you have to get power back to land, a lot more are needed to replace a powerstation, wind unreliable, visual
  1. Polltion, large areas of land required, some noise pollution, interfere with tv and radar signals, can kill wildlife, only some suitable places.
Definitions
1. Renewable energy: energy from sources that never run out.
2. Carbon-neutral: fuels that neither contribute to nor reduce the amount of carbon in the atmosphere
Tidal Power
1. Turbines generate electricity by being moved by tide twice.
2. Ad: tide is free, no pollution, no fuel, produces an ok amount.
3. Dis: Only happens twice a day, expensive for electricity, few potential sites, damning can effect enviro and local area, expensive to install
  1. may harm wildlife, restricts river access.
Wave power
1. 2 types: Pelamis sit on top of water and generate electricity by rise and fall. no. 2 traps water and the pressure of the wave coming in spins turbine
  1. Ad: wave is free, no pollution, large amounts of electricity (20 MW per Km)
  2. Dis: expensive electricity, only effective when there are strong waves, noisy, harm wildlife, hazard to boats, non constant supply, wires to mainland
Hydro-Electric
1. High region to lower, water flows from top of dam and turns turbines. In times of low demand water is pumped to top then released in high demand.
2. 1/6 of world electricity, 90% renewable.
3. Ad: operating costs are low, no pollution, reliable tech, large amounts of power, generated constantly, water is recycled, low electricity cost
4. Dis: Dams - expensive to build, large scale flooding, may harm marine/wildlife, limited potential sites, in remotes areas which costs to travel
Solar Power
1. Photo-voltaic cells are used to capture and transfer energy.
  1. Thermal: water pipes under black matt surface (heat water)
  2. Electric: solar cells flow through 2 types of silicon and knock electrons out, 1st layer - negative effect, 2nd positive charge.
    1. Then flow in opposite directions across Pn junction to create current.
2. Useful in remote areas, when small amounts of power is needed
3. Ad: Sun is free, low running costs, no pollution, electricity s generated where it will be used, cost with decrease with improved tech
4. Dis: doesn't work at night, photovoltaic cells are expensive, power output is low, large areas are required for reasonable power output, expensive.
Carbon Capture
1. Capturing waste carbon dioxide and storing it e.g. underground.
2. Ad: reduces CO2 from the air, old oil/gas fields can be used as storage space.
3. Dis: expensive, cannot be used at sea.
Geothermal
1. Natural heat within the earth, sometimes heat can rise to the surface in liquids or gases near plate tectonic boundaries.
  1. We drill 6km into the earth and dump water into the hole. The earth heats the water which turns to steam and turns a turbine.
2. Ad: operating systems are low, no pollution
3. Dis: no many sites, drilling through some rock is difficult, dangerous gases and minerals can be omitted.
The National Grid
1. Electricity travels from powerstation to cables
  1. Step up transformer; turns voltage up and current down to inhibit heat loss along lines
    1. step down transformer turns voltage down so house hold appliances can use power and current up.
      1. Substation turns voltage down (adapter) to safe levels
    2. Heat loss every sec or the Power = I times I R(I = current, R = resistance of wires)
2. Over Ground: spoil landscape, may effect health, high above ground.
3. Under ground: hard to repair, expensive, are not far underground so could affect people more.

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Generating Electricity

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	Creado por Grace Pulling hace más de 11 años