Traditionally, end users of gas or electricity have been categorized according to the rate class they were placed in by their local utility. Common classes for electricity customers include residential, commercial, industrial, agriculture, electric vehicles, and wholesale. Common classes for gas customers include residential, commercial, industrial, electric generation, cogeneration, natural gas vehicles, and wholesale. Typically, customers in different rate classes are charged different rates and have different rate structures.
Different customer classes have varying usage patterns since they use energy for different needs. Below are annual usage patterns by customer class for electric and natural gas customers in the United States: