Energy management isn’t always about energy, but it is always about dollars.
For some business customers, demand charges dominate the bill, especially when large demands occur for short periods of time. When short-term demands are increasing demand charges, this is a prompt for demand control. Methods vary but the point is to lower short-term demands – usually by ‘spreading out’ the energy use over time, smoothing out the usage pattern.
One form of self-help for demand cost control is treating short-term large demands that stem from the ‘catch up’ responses - called step changes - such as:
- Coming out of unoccupied mode.
- Going from idle to event mode.
- Coming out of hibernation mode.
The general solution is a combination of load limiting large loads, or an array of small loads, with early start. Interval data is an excellent tool for spotting errant demand patterns and focusing efforts, and can be found on the utility customer portal at no charge.
- For heating and cooling equipment, extra time is needed but the energy use is the same.
- For customers that already have a robust automatic control system, adding some demand control logic can produce savings with no capital outlay other than time.
- Manual solutions are possible, but automation is usually more successful because the utility demand savings require the benefit to be persistent.
Equipment with built-in ‘load limiting’ features are an enabler for demand limit control. A useful business strategy when selecting or replacing equipment is to consider demand limiting capabilities for chillers, heaters, fans and lights so they make it easy to implement demand limiting control.
We just published a new efficiency article: Demand Control Strategies During Load Step Changes that provides more details and some specific examples, including different ways demand charges can impact your bill.
While the article provides a good start, each facility and process is unique, and the operator’s expertise can find other ways to reduce demand charges and reduce utility expense in general. Sometimes a habit change is all it takes.