Energy return is the amount of usable energy obtained from the conversion of some form of energy into a useful form that can be used to produce other goods. Broadly speaking, it is a measure of the efficiency of an energy conversion process. The higher the energy return, the more efficient the process and the higher the net energy surplus that can be obtained from it. It is important to distinguish energy return from energy production – energy return on investment (EROI) measures how much energy is obtained from the energy investment and is typically measured in terms of the ratio of energy obtained over energy invested.

See also: fossil fuel, renewable energy, nuclear power, solar panel, wind turbine