Every power bill has two main components - a charge for the energy consumed, measured in kWh, and a charge related to the highest draw of electricity in a particular period – ‘peak demand’, aka ‘Capacity’ charge - measured in kW.

It gets worse! You can be billed twice for peak demand – once by your utility company which delivers the power, and again by your 3rd party power-supply company (e.g. Constellation), so lowering your peak demand can lower your total bill substantially.

Depending on your location, demand charges can amount to more than 30% of your electrical bill. Focusing energy-saving techniques on usage alone, and not demand, limits potential savings. Even a single peak as short as 15-minutes, can affect a monthly energy bill significantly.

Peaks on certain days are higher (10-15%) than average demand

To “attack” your power bill, you should monitor not only the amount of energy used each billing period, but also how and when a peak demand period is established. With thoughtful energy monitoring on large machines, production equipment, or lighting, contributions to any peak can be identified.

Strategies for lowering peak demand vary. Some solutions involve moving loads to “off-peak” periods when demand is lower, e.g. by using ice-storage to reduce chiller usage. Other solutions involve scheduling equipment to run only at certain times, or not to run when other high-energy users are operating.

Identifying electrical loads contributing to peak demand requires submetering or energy monitoring at a granular level.

Overall Peak was set by multiple heating elements coming online at the same time

At this example site, heaters coming online simultaneously caused a spike in usage. Heat was not required for production at the specific time, but plant personnel were energizing equipment in preparation for an upcoming shift. If plant personnel started heaters earlier or waited between when machines were energized and brought to temperature, the plant could have avoided upwards of 100 kW in peak demand, translating to hundreds or thousands of dollars in savings per billing period!

SiteWatch can identify the main contributors to peak demand enabling customers to lower the peaks by spreading the load out over longer periods.