Identify the annual energy consumption for each fuel or source
Convert all energy use to a common unit, such as kWh or BTU
Sum the annual energy consumption across all sources
Divide the total annual energy consumption by the relevant area, output, or population, depending on the AEC definition being used
Use the formula: AEC = Total Annual Energy Consumption / Relevant Base
If needed, apply any required adjustment factors specified by the standard or method you are following