P3

P3

1. Electrical Energy

   • Power is the rate of energy transfer
   • Energy transferred=power x time
   • Power=Voltage x Current
   • Efficiency=energy usefully transferred/total energy supplied

2. Sankey Diagrams

   • Energyy is always conserved even if it's wasted
   • Thickness of arrow represents amount

3. Saving Energy

   • Home
     • Hot water tank jacket
       • Double glazing
         • Energy saving bulbs
           • draught proofing
             • loft insulation
         • Turn unused appliances off
   • Public transport/car share/cycling/walking
     • Recycling

4. Energy Sources and Power Stations

   • non renewable fuels
     • Fossil fuels; coal, oil, natural gas
     • Nuclear fuels (uranium, plutonium)
   • Renewable fuels
     • wind
       • waves
         • Tides
           • Hydroelectric
             • Solar
         • Biofuels
           • Geothermal

5. Nuclear Energy

   • Release energy by splitting atoms
   • Heat evaporates water, steam drives turbine, generator converts kinetic energy into electricity

6. Biofuels, Geothermal and Hydroelectricity

   • Biofuels are made from plant waste
   • Geothermal energy is heat from underground
   • Hydroelectricity uses dams to catch the rain
     • Requires flooding a valley

7. Generators and the National Grid

   • Moving a magnet in a wire coil induces a voltage
     • As you move the magnet through the coil the magnetic field in the coil changes and and induces a voltage and a current if the circuit is complete
   • Energy is distributed via the national grid
     • Distributed at a high voltage
       • High current loses too much heat

8. Comparison of energy resources

   • Coal
     • 36% effiicient
     • 8000 million units produced/year
     • 920g CO2 per Unit
     • Site life- 50 years
     • Cost of energy-2.4-4.5p
   • Gas
     • 50% efficient
     • 5000 million units produced/year
     • 440g-CO2 per unit
     • Site life- 30 years
     • Cost of energy- 2-3p
   • Nuclear
     • 38% efficient
     • 7000 million units produced per year
     • 110g- CO2 per unit
     • Site life 25 years
     • Cost per unit- 4-7p
   • Wind
     • 35% efficient
     • 150 million units produced/year
     • 0g -CO2 per unit
     • Site life 25 years
     • Cost per unit- 3-4p