Peak Demand

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Power demand across the grid follows a reliable pattern each day. At night, when very little power is being consumed, demand is at its lowest. During this period the grid is supplying its base load of power. As people wake, go to work, and turn on their appliances, power demand gradually approaches its daily peak, called peak demand. In order to balance demand with supply, power plants known as "peaker plants" are incrementally brought online throughout the day. If it's a particularly hot day where homes and buildings are using air conditioning, then peak demand will be especially high.

A combination of factors can lead to power shortages and electrical emergencies during days like this. First, there is a smaller margin between peak demand and peak load, the maximum transmission capacity that the grid can supply. Unscheduled transmission disruptions due to equipment failures or wildfires destroying transmission lines can exacerbate the situation. If the Independent System Operator is concerned about sustaining the grid's operating reserves between 6 and 7%, they will issue a Stage 1 Electrical Emergency, including a request to conserve energy.

There are two strategies to lower Peak Demand:

  1. Energy Conservation: Simple conservation actions go a long way. Turning off unnecessary lights and appliances, and adjusting thermostats to 78º or higher will both significantly lower power consumption.
  2. Offsetting demand to non-peak hours: Waiting until after 6 p.m. to turn on washers and dryers offsets electricity demand to a time when the grid is less stressed, freeing up more electricity during peak hours.

Many utility companies in the state offer Demand Response programs for commercial facilities, and sometimes residences. View our Demand Response page for more information.