Energy management involves the study of the production of energy through natural resources, such as the extraction of oil and gas, as well as from renewable or sustainable sources of energy, including biofuels, hydro, wind, and solar power. Energy engineers are also taught how to find efficient, clean and innovative ways to supply energy. They work in a variety of roles including designing and testing machinery; developing ways of improving existing processes; converting, transmitting and supplying useful energy to meet our needs for electricity.