National Grid and Electricity Distribution

Overview

• Purpose: Distribute electricity from power stations to 25 million homes in the UK.
• Components: System of transformers and high-voltage cables collectively known as the National Grid.

Sources of Electricity in the UK

• Over 50% from burning fossil fuels.
• 25% from renewables (e.g., wind power).
• Around 20% from nuclear power.
• Remainder is imported from Europe.

Challenges in Electricity Distribution

• Energy Loss: Occurs due to the resistance of wires in power cables.
• Distance Factor: Greater distance between power stations and homes increases energy loss.
• Solutions:
  • Building power stations near homes is impractical.
  • Use of transformers to manage and reduce energy loss.

Role of Transformers

Step Up Transformers

• Function: Increase the potential difference to several 100,000 volts.
• Purpose: High potential difference results in less energy loss in cables.
• Exam Tip: Always mention that 'less energy is lost', not 'less electricity is lost' to secure marks.

Step Down Transformers

• Function: Reduce the potential difference to around 230 volts.
• Purpose: Make electricity safe for use in homes, as high potential differences are too dangerous for direct home use.

Key Facts Recap

• The National Grid consists of transformers (step up and step down) and high voltage cables.
• Step Up Transformers: Increase potential difference to reduce energy loss.
• Step Down Transformers: Decrease potential difference for safe home usage.

• Additional resources like the revision workbook with questions on the National Grid are available for further study.