Support your students to: Understand what is meant by a power rating. Calculate the cost of running different devices in the home. Convert between units for power and time. Understand how prefixes are used for SI units. Lesson overview: This resource explores the concept of electrical device power within the context of clean renewable tidal energy available in the waters surrounding the UK. Students will investigate how much power can be generated from the clean energy resource, tidal turbines. This lesson also explore how much power our domestic appliances require.