Environmental Issues (AQA GCSE Physics): Revision Notes

1.2.3 Environmental Issues

The UK Energy Mix

Historical Overview

• Abundant Reserves of Coal:
  • Up until the 1950s, almost all of the electricity generated in the UK came from burning coal.
  • Coal and coal gas were also used for almost all heating and cooking in the UK.
• Nuclear Power:
  • In the 1950s, nuclear power came online.
  • By the 1980s, it produced around 20% of all the UK's electricity.
• Oil and Gas:
  • In the 1970s, the UK became a major producer of oil and gas from the North Sea.
  • This began to replace coal for electricity generation.
• 2000s:
  • By 2000, as much electricity was generated from burning gas as from coal.

Switch from Coal to Gas

• Environmental Impact:
  • Burning gas generates less carbon dioxide than burning coal, contributing less to climate change.
• Operational Flexibility:
  • Gas-fired power stations are flexible and can be switched on quickly during periods of high demand (short start-up time).
  • Coal-fired power stations have a very long start-up time.

Switch to Renewables

• Realisation in the 1970s:
  • Scientists began to realise that CO2 emissions from human activity could be leading to climate change.
  • At the time, politicians did not see this as a big issue.
• Economic Factors:
  • Energy from fossil fuels was very cheap, making it economically challenging to switch away from fossil fuels.
• International Agreements:
  • In 2005, the Kyoto Protocol committed countries to reducing greenhouse gas emissions.
• Wind Power:
  • The UK has one of the best locations for wind power in the world, but it is not very reliable.
• Baseload Power:
  • A baseload of reliable energy is needed, and nuclear power is ideal for this.

Future Energy Mix

• Gas-fired Power Stations:
  • Provide emergency power in times of peak demand.
• Renewables:
  • Will provide the bulk of our electricity.
  • Nuclear power will provide a base load.
  • Gas will provide electricity during periods of peak demand.

Renewable Energy Resource

Comparison of Renewable Energy Sources

Energy Source	Advantages	Disadvantages
Solar Power	Never runs out. Does not contribute to climate change once in place.	Not reliable.
Wind Power	Never runs out. Does not contribute to climate change once in place.	Not reliable.
Hydroelectric Power	Never runs out. Does not contribute to climate change once in place. Very reliable.	Habitats are destroyed (dams, flooding). Only useful in countries with lots of rivers.
Tidal Power	Never runs out. Does not contribute to climate change once in place. Very reliable.	Structures harmful to wildlife.
Wave Power	Never runs out. Does not contribute to climate change once in place. Very reliable.
Geothermal Energy	Never runs out. Does not contribute to climate change once in place. Reliable (not used very much in the UK).
Biofuels	Never runs out. Does not contribute to climate change once in place. Carbon neutral.	If we use land to grow crops for fuel, that could push up the price of food.