The primary fuels are coal, oil, natural gas, nuclear, hydro, biomass, and renewables, but these are not the forms of energy we encounter most often. Other than driving a car and heating a home, the form of energy we are most accustomed to comes from turning on a switch. We use electricity for lighting and running all sorts of electrical appliances and equipment. It is absolutely essential to running a modern economy. Yet, electricity is a secondary form of energy derived from primary fuels. This chapter deals with electricity as a source and use of energy, its origin, the organizational structure of utilities, system operation, and models for determining rates.