Demand Response in Electricity Systems

Demand response means a deliberate change in consumers' electricity use in response to grid conditions, electricity prices or incentive payments. It makes electricity demand flexible by reducing, shifting or sometimes increasing consumption at particular times, rather than treating demand as fixed.

How demand response works

The grid must continuously balance electricity supply and demand. During scarcity or peak demand, consumers may reduce or postpone flexible loads; during surplus generation, especially from variable renewable sources, they may advance or increase suitable consumption.

• Price-based response uses time-varying tariffs, such as time-of-day or critical-peak pricing, to encourage consumers to shift consumption.
• Incentive-based response pays participating consumers for reducing load when called upon by the system operator or electricity supplier.
• Smart meters, communication systems and automated controls can enable faster and more accurate responses, although consumers may also respond manually.

Role in grid management

Demand response functions as a demand-side flexibility resource. It complements generation, storage and transmission measures by adjusting consumption when the grid is under stress or has surplus electricity.

• It can reduce peak demand, lowering the need to operate expensive peaking generation or add capacity used only for short periods.
• It supports reliability by helping correct short-term supply-demand imbalances and relieving network congestion.
• It can improve renewable-energy integration by shifting consumption towards periods of high solar or wind generation.
• It may lower system costs and, where tariffs transmit these savings, reduce costs for participating consumers.

Limits and distinction from energy efficiency

Effective programmes require suitable tariffs or contracts, reliable metering, communication infrastructure, consumer consent and a credible method for measuring the demand change. Poorly designed programmes may cause inconvenience, weak participation or merely shift the peak to another period.

• Demand response changes the timing or level of consumption according to system conditions; energy efficiency produces a more persistent reduction in electricity needed for a given service.
• Essential and inflexible loads have less scope to participate than industrial processes, cooling, pumping, charging and other controllable uses.