Generation, Transmission & Distribution of Electricity

Electricity Supply Overview

• Understanding where electricity comes from and its journey to homes and businesses involves multiple stages.

Stage 1: Generation – How Electricity is Produced

• Sources of Electricity:

  • Renewable Energy Sources:

    • Wind

    • Solar

    • Hydropower

    • Bioenergy

  • Non-renewable Energy Sources:

    • Coal

    • Fossil Fuels

    • Nuclear Power

• Renewable Energy Benefits:

  • Cleaner, greener, and cost-effective compared to non-renewable sources.

  • Usage is prioritized, but reliance on non-renewable sources continues when renewable generation is low.

• Electricity Market:

  • Generated electricity is sold on the wholesale market to energy suppliers.

Stage 2: Transmission – Sending Electricity Around the Country

• Transmission Network:

  • Functions similarly to motorways, transporting high-voltage electricity from generation points.

• Role of National Grid:

  • Manages the electricity transmission network including pylons, overhead lines, and underground cables.

  • Responsible for building and maintaining infrastructure to carry electricity across England and Wales.

Stage 3: Distribution – How Electricity Reaches Homes

• Connection to Communities:

  • Distribution networks act like local roads, linking transmission networks to neighborhoods.

• Voltage Management:

  • High-voltage electricity is stepped down at distribution substations for safe use in homes.

• Regional Management:

  • Local distribution network operators manage the poles, cables, and substations.

  • In the Midlands, South West England, and South Wales, the National Grid operates the distribution.

Voltage Identification

• Live Generation Data and Voltage Levels:

  • Generation voltage: 25kV

  • Transmission (Grid system): 400kV or 275kV

  • Distribution (locally): 132kV, 66kV, 33kV, 11kV, 400/230V

  • Other voltages may be encountered.

  • Transformers are essential for stepping up and down voltage levels to manage current and power effectively.

Additional Notes

• Direct Current (D.C.) Transmission:

  • A D.C. line between the UK and France mitigates normal A.C. losses.

  • High voltage is not suitable for end-users; transformers reduce it to safe levels.