At the end of a warehouse shift, forklifts plug in to charge while conveyors are still running and the HVAC system is working to cool the building. If those loads overlap long enough, the warehouse could set a new monthly electricity demand peak. Moving some charging to a quieter part of the shift schedule could lower that peak while the forklifts still get the same amount of charge.
How A Short Spike Can Affect A Full Month’s Bill
Electricity consumption is measured in kilowatt-hours (kWh). Demand measures how quickly a facility draws electricity and is expressed in kilowatts (kW). If a utility rate includes a demand charge, the utility may base it on the highest average draw over a short interval, often 15 minutes. The applicable rate determines which intervals count and how the utility calculates billed demand. nZero
Consider a warehouse that lowers its billed demand from 300 kW to 270 kW by spreading out forklift charging. At an illustrative rate of $15 per kW, that would reduce the demand portion of the bill by $450 for the month, assuming the rate applies directly to the measured peak. The warehouse could still use the same total amount of electricity.
Find Out What Was Running When Demand Peaked
Start with the facility’s interval meter data, if available, and compare the highest readings with shift schedules, equipment logs, or building automation records. Look for patterns. Does demand spike when several production lines start together? Does the building hit its peak when HVAC equipment ramps up at the same time as compressors or chargers?
Then look for loads with some scheduling flexibility. A warehouse might charge forklifts in groups. A manufacturing plant might stagger equipment startups where the production sequence allows. A commercial property might review when large HVAC systems start each morning. nZero
Check Whether The Change Lowered Billed Demand
After adjusting a schedule, review the next billing cycle’s interval data and billed demand. Check whether the original peak came down and whether another time of day became the new high. If the rate also includes time-of-use pricing, check how the shift affected energy charges. For a facility managing operating expenses, the measure that matters is what changed on the bill.
Source: NZero