The reasons for the changing global demand for energy, the effectiveness of renewable and non-renewable approaches, and the suitability of renewable approaches in a chosen area.

What this key area is asking

The SQA wants you to explain why global energy demand is changing, judge how effective renewable and non-renewable sources are, and assess how suitable renewable approaches are in a chosen area such as Scotland. Higher marks depend on a named area and a clear judgement.

Changing demand for energy

Global demand is rising because of population growth (over $8$ billion people), the economic development and industrialisation of countries such as China and India, and higher living standards that use more transport, electrical goods and heating. Supply is shifting because fossil fuel reserves are being depleted and there is strong pressure to cut carbon emissions to slow climate change.

Renewable and non-renewable sources

The most effective real-world supply is usually a mix of sources, so that reliable baseload (nuclear, gas, hydro) covers the intermittency of wind and solar.

Suitability of renewables in Scotland

The best renewable choice depends on an area's physical geography. Scotland is well suited to renewables:

• Wind power. Exposed western and northern coasts, uplands and offshore areas are consistently windy, so onshore and offshore wind farms (such as Whitelee, south of Glasgow, with over 200 turbines) are highly productive, though some object to the visual impact and bird strike.
• Hydroelectric power. The high rainfall and steep, glaciated Highland valleys are ideal for dams and reservoirs, giving reliable, storable power (such as the Cruachan pumped-storage scheme).
• Tidal and wave power. The strong currents of the Pentland Firth suit tidal arrays such as MeyGen.

Other areas suit different sources: deserts suit solar power, volcanic regions such as Iceland suit geothermal, and coastlines with a large tidal range suit tidal power.

Examples in context

Example 1. Whitelee Wind Farm, Scotland. Whitelee, on Eaglesham Moor south of Glasgow, is one of the UK's largest onshore wind farms, with over 200 turbines and a capacity of around $539\ MW$. Its location works because the exposed, high moorland is consistently windy and close to the central-belt grid and population. It shows why Scotland suits wind power, while also illustrating the trade-offs of visual impact on open moorland and the intermittency that means it cannot run without backup. It is the standard named renewable example.

Example 2. Iceland's geothermal energy. Iceland sits on the Mid-Atlantic Ridge, a constructive plate boundary with abundant volcanic heat near the surface. It generates almost all its electricity from renewables, with about a quarter from geothermal and most of the rest from hydro, and uses geothermal heat directly for district heating. The contrast with Scotland shows that renewable suitability is dictated by physical geography: geothermal suits volcanic Iceland, while wind and hydro suit windy, wet, mountainous Scotland.

Try this

Q1. Explain the reasons for the rising global demand for energy. [4 marks]

• Cue. Population growth; the economic development and industrialisation of countries like China and India; higher living standards with more cars, appliances and heating.

Q2. For a named area, explain why it is suited to a renewable energy source. [4 marks]

• Cue. Scotland: windy exposed coasts and uplands suit wind power; high Highland rainfall and steep glaciated valleys suit hydroelectric power; strong tides suit tidal power.