The National Grid

• National Grid


  A giant web of wires that covers the whole of Britain, getting electricity from power stations to homes everywhere
• National Grid


  • Connects power stations to consumers (anyone who is using electricity)
  • Transfers electrical power from power stations anywhere on the grid (the supply) to anywhere else on the grid where it's needed (the demand)
• Electricity Production has to Meet Demand

  1. Electricity usage (the demand) changes throughout the day

  2. Power stations have to produce enough electricity for everyone to have it when they need it

  3. Power stations can predict when the most electricity will be used

  4. Power stations often run at well below their maximum power output to cope with high demand

  5. Lots of smaller power stations that can start up quickly are also kept in standby just in case
• Transformer


  A device used to efficiently transfer electricity by increasing the potential difference and decreasing the current
• Potential Difference is Changed by a Transformer

  1. Transformers step the potential difference up at one end for efficient transmission

  2. Transformers then bring the potential difference back down to safe, usable levels at the other end

  3. Step-up transformer increases the potential difference

  4. Step-down transformer decreases the potential difference
• Transformers are almost 100% efficient
• Increasing the potential difference

  Decreases the current, which decreases the energy lost by heating the wires and the surroundings
• Power is the energy transferred in a given time, so a higher power means more energy transferred