Energy Resources and Energy Transfers (Paper 2)

Explained

Energy resources, and the transfer chain they all share

Nearly every power station does the same thing. Something heats water, the steam turns a turbine, and the turbine turns a generator. Once you see that, the differences between resources come down to what supplies the heat and what that costs the environment.

The standard chain

Burning a fossil fuel or biomass transfers energy from a chemical store to a thermal store, then to a kinetic store in the turbine, then to electrical working in the generator.

A nuclear station is identical after the first step. It begins with a nuclear store rather than a chemical one, then follows exactly the same thermal, kinetic and electrical route.

Wind, hydroelectric and tidal stations skip the heating stage. The moving air or water already has a kinetic store, and that turns the turbine directly.

The two solar devices are not the same

A solar cell transfers energy carried by radiation directly to electrical working. No turbine, no generator, no moving parts.

A solar heating panel does something different. It transfers energy carried by radiation to a thermal store, usually in water for washing and heating rather than for generating electricity.

Confusing the two is a common way to lose a mark, so read which one the question names before you start writing.

Renewable and non-renewable

A non-renewable resource is used faster than it is replaced, so the supply runs down. Coal, oil, gas and nuclear fuel are all non-renewable. A renewable resource is replaced as fast as it is used, so it does not run out. Wind, waves, tides, hydroelectric, geothermal, solar and biomass are renewable.

Comparing resources without waffling

Answers improve when each point names the resource, states the property, and says why it matters. Nuclear releases no carbon dioxide during generation but produces radioactive waste that stays dangerous for a very long time. Wind releases no carbon dioxide but generates nothing when the wind drops, so it is unreliable. Gas can be started quickly to meet a sudden rise in demand, which coal and nuclear cannot.

Reliability, start up time, running cost, set up cost and environmental effect are the five headings worth having ready. Choosing two of them and explaining both beats listing all five without reasons.