Load forecasting

A day-ahead electric demand forecast

Load forecasting is the process of creating a forecast of the amount of gas or electric load expected on a system during a specified period of time. This can be done from either a short-term or a long-term perspective. The forecast may include both overall usage and peak demand. Load forecasting is used for multiple purposes:

  • Designing gas and electric transmission and distribution systems so that sufficient capacity exists to serve peak demands
  • Determining expected usage for the purposes of setting rates
  • Determining required amounts of supply seasonally and annually to ensure gas and electric reliability
  • Sizing services into specific customer facilities
  • Planning system operations on a day-by-day and intra-day basis
  • Scheduling daily and/or hourly supplies and deliveries for competitive energy markets


Forecasts of expected loads are derived from models based on detailed historical statistics, weather patterns, and consumption patterns driven by factors such as the day of the week or the time of the year. Long-term forecasts are also impacted by demographic forecasts, expectations for business growth or decline, technology changes, energy efficiency improvements, and changes in customer behaviors.