What everyone needs to know:
This topic needs you to understand the main sources of energy used today. There are fossil fuels (coal, gas, oil), nuclear fuels and renewable sources such as wind, hydroelectric, geothermal, tidal, waves and solar.
Renewable energy sources are being replaced as we use them (eg more sunlight is arriving from the sun or if you plant more trees than you cut down and burn).
You need to be able to describe the sources, say if they are renewable or non-renewable (nuclear is non-renewable by the way), compare outputs, efficiency and pollution etc and discuss reliability. You may have graphs and data to interpret.
Patterns in usage (half time of the FA cup final, millions of kettles go on), describing the environmental effects and why people may be opposed to wind farms or nuclear power stations.
Extra topics needed for the Higher papers:
In this topic, there is nothing extra for the higher papers, the questions will just be more challenging.