A demand charge is a fee assessed by utilities based on the peak power consumption level reached during a billing period, separate from the standard energy consumption fee. Rather than charging only for total kilowatt-hours used, demand charges penalize customers for their highest instantaneous power draw, typically measured in kilowatts (kW). For commercial and industrial customers, demand charges often represent 30-70% of total electricity bills, making peak demand reduction a critical cost control strategy.
How Demand Charges Work
Utilities establish demand charges at rates between $5 and $30 per kW per month, depending on location and customer classification. The charge applies to the single highest 15-minute interval of power consumption during the month. A facility consuming 500 kW at peak incurs monthly demand charges of $2,500-$15,000 independent of total energy consumed.
Impact on Energy Management
Demand charges incentivize strategies including load shifting to off-peak periods, installation of battery storage systems to reduce peak draws, and use of demand response programs. Facilities implementing demand management typically reduce monthly bills by 15-40% while improving overall energy efficiency.
Strategic Reduction Methods
Microgrids, thermal storage systems, and load scheduling reduce peak demand through distributed generation and storage, allowing facilities to lower charges significantly without reducing overall productivity.