Been auditing a large manufacturing client in Cleveland and their FirstEnergy interval data is showing these bizarre demand spikes right at midnight on weekdays. We're talking 200-300 kW jumps that last exactly 15 minutes then drop back to normal. Client swears nothing is scheduled to run at that time. Anyone seen this before? Could this be a meter issue or some kind of utility system artifact?
FirstEnergy interval data showing weird spikes at midnight?
Frank, I've seen similar patterns with Duke Energy here in Charlotte. Turned out to be automatic load transfer switches doing self-tests. Check if they have any backup generators or UPS systems that might cycle at midnight. Also worth checking if the building automation system has any scheduled routines that could be kicking on motors or HVAC equipment.
Derek's on the right track. I had a case in Dallas with Oncor where the interval data showed consistent spikes at 11:58 PM. Facility manager finally admitted they had a large compressor system that did automatic purge cycles. Customer was getting hit with demand charges of $800+ monthly because of those 15-minute windows. We moved the purge cycle to off-peak hours and saved them $9,600 annually.
Frank - also check the interval timestamps carefully. Sometimes there are daylight saving time issues where the utility's data collection system creates phantom readings during the spring forward/fall back transitions. CPS Energy in San Antonio had this problem for years. If the spikes only happen on certain dates, that might be your culprit.
Great suggestions everyone. Derek, you nailed it - they DO have a backup generator with weekly self-test cycles. But get this - the test is supposed to run on Sundays at 2 PM, not weekdays at midnight. Looks like someone reprogrammed it without telling facilities management. The midnight spikes are costing them about $45 per occurrence in demand charges on their GS-3 rate schedule.
That's a classic! Here in Louisville with LG&E, I see this all the time with older facilities. The maintenance staff changes programming but doesn't coordinate with accounting or energy management. Always check the building automation logs against the interval data. Saved a client $12K last year just by moving their water heater cycling from peak to off-peak hours.
Frank, make sure you document the before/after interval data for your report. TVA here in Knoxville loves to see that kind of detailed analysis when we're negotiating rate changes. Also recommend setting up automated alerts if their energy management system supports it - catch these issues before they become expensive problems.
Update: Got the generator test moved back to Sunday afternoons. November bill came in $1,340 lower than October just from eliminating those midnight demand spikes. Client is thrilled. Thanks for the troubleshooting help everyone - this forum saves me so much time!