Peak demand is the highest point of electricity consumption, usually occurring on hot summer afternoons when air conditioning use surges. Utilities must maintain enough generation capacity to meet peak demand plus a reserve margin. Peak events are expensive because they may require activating less efficient and more costly peaker plants. Managing peak demand through demand response programs, time-of-use pricing, and energy storage is a major focus of modern grid management.
Peak Demand
The maximum electricity consumption in a grid during a specific period, typically hot summer afternoons.
Related Terms
Demand Charge
A fee based on the maximum rate of electricity consumption (peak demand in kW) during a billing period.
Time-of-Use (TOU) Rates
Pricing that varies by time of day, with higher rates during peak demand hours and lower rates off-peak.
Base Load
The minimum level of electricity demand over a 24-hour period, typically supplied by always-on power plants.
this entity is one of the U.S. state-level electricity rates and generation mix concepts that recurs across this site. The definition above is the technical answer; the paragraphs below add the practical context for how the concept connects to the the EIA Open Data API and State Electricity Profiles data behind every per-entity page on the site.
In the the EIA Open Data API and State Electricity Profiles data, this concept shapes one or more of the fields that drive the per-entity grades and rankings on this site. The methodology page describes which fields feed into which output; this glossary entry documents the underlying term.
Source: U.S. Energy Information Administration, 2026.