GCSE Revision

Increasing energy supply

Renewable and non-renewable energy

Non-renewable sources will run out:

  • coal, oil and gas, which release carbon dioxide when burned;
  • nuclear power, which uses uranium.

Renewable sources won't run out:

  • wind, solar, hydroelectric (moving water), tidal and wave power;
  • geothermal power, from heat underground;
  • biomass: burning plants or plant waste.

To increase supply, countries can extract more fossil fuels, often from harder places, or build more renewable and nuclear power. Renewables release far less carbon, but wind and solar vary with the weather.

Key terms

Extracting a fossil fuel: the Alberta oil sands

The of Alberta, in western Canada, hold huge amounts of , a thick, heavy oil mixed with sand and clay.

  • They hold about 167 billion barrels of proven oil reserves, according to the Alberta Geological Survey.
  • They produced just under 3.5 million barrels a day in 2024, according to the Canada Energy Regulator.

The bitumen is extracted in two ways:

  • surface mining: where it is near the surface, forest is cleared, and giant diggers and trucks remove the sand;
  • in situ: where it is deep, steam is pumped underground to heat the bitumen so it flows and can be pumped up.

Key terms

Advantages and disadvantages

Advantages:

  • jobs, for Canadians and in supply industries;
  • for Alberta and Canada;
  • a secure supply for Canada, and exports, mainly to the USA.

Disadvantages:

  • extracting and processing bitumen uses huge amounts of energy and water, so it releases more per barrel than most other oil;
  • toxic waste water is stored in vast , which can leak and harm wildlife;
  • forest and peatland are cleared for mines;
  • First Nations communities downstream worry about pollution of rivers and the effects on their health and way of life.

Exam tip

Make a judgement: do the economic gains outweigh the environmental costs?

Key terms

Exam practice

Plan your own answer first, then open the model answers to see what each level looks like.

9 marks · about 9 minutes

To what extent do the economic advantages of extracting a fossil fuel outweigh the environmental costs?

To what extent means: Weigh up how far something is true, with evidence on both sides, then give a clear judgement.

Link it

Use the facts from:

Level 1 (Basic)· 3/9 marks (band 1–3)
The oil sands in Canada make money and jobs, but they pollute. I think the costs are bigger.

Why this level: Simple points with no detail and an unsupported judgement. To reach Level 2: use facts to explain the economic advantages and the environmental costs.

Level 2 (Clear)· 5/9 marks (band 4–6)
Alberta's oil sands produced just under 3.5 million barrels a day in 2024. They bring jobs, taxes and royalties, and secure energy for Canada, with exports mainly to the USA. However, extraction uses lots of energy and water, so it releases more greenhouse gas per barrel than most oil, and toxic waste water is stored in tailings ponds.

Why this level: Clear, accurate advantages and costs. But they aren't weighed, and there's no judgement. To reach Level 3: compare short-term and long-term effects, and who is affected, then conclude.

Level 3 (Detailed)· 8/9 marks (band 7–9)
Alberta's oil sands bring large economic advantages. They hold about 167 billion barrels of proven reserves and produced just under 3.5 million barrels a day in 2024. This creates jobs, and taxes and royalties help fund public services, while giving Canada secure energy and exports, mainly to the USA. However, the environmental costs are serious. Shallow bitumen is surface-mined after forest is cleared, destroying habitats, and deeper bitumen is heated with steam, so extraction uses huge amounts of energy and water. As a result, it releases more greenhouse gas per barrel than most oil, adding to climate change. Toxic waste water is stored in tailings ponds, and First Nations communities downstream worry about river pollution. Overall, the economic advantages are large, but they are mostly short-term and depend on oil prices, while the environmental costs are long-lasting and global, so they don't clearly outweigh them.

Why this level: Detailed, accurate evidence on both sides, weighed by timescale and who is affected, with a justified judgement. This is Level 3.

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