Peak Demand

The demand-forecasting procedure in the Electricity Market Operation Rules defines peak load as the largest hourly average of electricity demand, and divides it into annual, monthly, weekly and daily peak load by period. News reports often call it 'maximum power'.

Peak demand is the yardstick for how much capacity the system needs. The government's Basic Plan for Electricity Supply and Demand projects long-term peak demand to plan generation and transmission facilities, and peak load is also used in calculating capacity payments. In Korea, peak demand runs high in summer and winter, when cooling and heating demand concentrate.

News-reading tip: a 'record peak demand' story means demand has grown, not that electricity is immediately running short. Read it together with the reserve margin. The 'maximum demand power' on a KEPCO bill is a single customer's metered value, a different concept from national peak demand.