Regional grocery chain in Charlotte just got destroyed by Duke Energy's GP-5 demand charges. Five stores, each with 3-4 large rooftop units that cycle simultaneously when outdoor temps hit 85+. Demand spikes are hitting 400-500kW per store during afternoon hours. At $19.86/kW summer demand rate, they're looking at $8,000-10,000 monthly demand charges per location. Store managers have no clue why electric bills doubled this summer. Corporate is panicking and wants answers.
Duke Energy GP-5 schedule nightmare with grocery store HVAC
FirstEnergy GP schedule here - similar pain points. Grocery stores are tough because they need consistent temperatures for food safety but have huge HVAC loads. The simultaneous cycling is usually due to a single thermostat controlling multiple units or poor sequencing programming. First step is always staging the equipment starts with time delays between units.
PSO territory - we see this with big box stores too. The problem is that most HVAC controls are installed by low-bid contractors who don't understand demand billing. They wire everything to start simultaneously because it's simpler. Derek, are these units on basic thermostats or do they have any building automation? Even a simple sequencing relay can solve 80% of the problem.
APS commercial customers deal with this constantly. The solution is usually a combination of staging controls and demand limiting. For grocery stores, I recommend setting demand limits at 120% of historical peak and programming the BMS to shed non-critical loads during HVAC startup events. Freezer cases can coast for 10-15 minutes without temperature issues.
Ed - these are newer stores with Honeywell building automation but apparently not configured for demand management. The BMS can see all the equipment but there's no logic programmed for staging or demand limiting. Corporate hired a controls contractor to reprogram all five locations. Should see results next month. Sarah's idea about load shedding is interesting - the deli equipment might be good candidates for short-term cycling.
City Utilities in Springfield - grocery stores are 30% of my client base. The key insight is that food safety requirements actually provide flexibility for demand management. Refrigerated cases have thermal mass and can handle 15-20 minute cycling delays during demand events. Health department regulations allow temporary temperature excursions as long as product stays below critical thresholds.
PPL here in Harrisburg - worked with a Weis Markets location on similar issues. We installed demand meters on each major load and programmed priority shedding. HVAC gets first priority, then refrigeration, then lighting and non-essential loads. The system sheds loads in 50kW increments when approaching the demand limit. Reduced peak demand by 200kW without any customer complaints.
Duke Energy Ohio territory - the other issue with grocery stores is power factor. Those big compressor motors create reactive power demands that add to apparent power. Make sure you're looking at both real and reactive power demand charges. Power factor correction capacitors can reduce total demand charges significantly, especially during startup events when motor power factor is worst.
Ameren Missouri - Cecilia raises a great point about power factor. Schedule LGS has both kW and kVA demand charges. Poor power factor during motor startup can increase apparent power demand by 20-30%. We always recommend power factor correction as part of any HVAC demand management project. The capacitors pay for themselves in 6-12 months typically.
TVA Schedule GSA customers face the same issues. Derek, definitely push for power monitoring on each major load. You can't manage what you don't measure. Real-time demand meters with trending capability will show exactly when and why the spikes occur. Usually reveals control logic problems that aren't obvious from just looking at monthly bills.
Alabama Power here in Huntsville - grocery chain clients always benefit from energy storage solutions too. Battery systems can provide startup power for large HVAC equipment and eliminate demand spikes entirely. Technology is getting more affordable and the demand charge savings usually justify the investment. Worth exploring for high-demand locations with frequent cycling issues.