The National Grid

• The national grid transmits huge amounts of power
• High current flowing through a wire generates lots of heat due to resistance
• Equation for power

  Power = Voltage x Current
• To avoid energy loss, current must be kept low, requiring high voltage
• Step-down transformers lower the voltage to around 230 volts before reaching its destination like a town
• Step-up transformers increase the voltage to around 400,000 volts for transmission across the country
• Electricity is transmitted between huge pylons
• Step-up transformers increase voltage to minimize energy loss during transmission, while step-down transformers lower it to make it safe for use
• Power stations need lots of spare capacity to cope with surges in demand and often run at well below their maximum power output
• Electricity demand peaks in the late afternoon and evening when everyone gets home from school or work and starts cooking and watching TV
• Most electricity is generated in power stations and transmitted through the national grid using transformers, wires, and pylons
• High voltages are dangerous and can damage appliances in houses
• Electricity generation in power stations

  1. Generated by power stations through burning fossil fuels or nuclear fission

  2. Generates heat and converts it into electrical energy