This activity gets pupils to calculate energy generated from a range of solar panels and work out the payback time from the current price per kWh given by the government (4.1p per kWh). The Solar panel comparison data.pptx can be printed out and the cards can be left around the room for pupils to gather data from. Pupils then have to draw a graph and write a letter based on two customers needs. Power, Energy, Time, Kilowatt hours, kWh, payback times, efficiency, literacy, formal letter.