Demand-side management, also known as load management, is used to control the demand for grid-connected services from commercial, industrial and residential customers. Demand-side management is primarily used for the demand for electricity in order to compensate for periods of congestion. Demand for electricity is reduced during times of congestion and demand is increased outside of congestion to compensate for this. The amount of electricity supplied remains the same in both phases, meaning that the amount of electricity purchased is only regulated by demand.