I'm working on a case with Westar Energy here in Kansas where the interval data clearly shows peak usage occurring during off-peak TOU hours, but the client is being billed at peak rates. The 15-minute intervals from March show 847 kW demand spike at 11:47 PM on weeknights, well outside the 1 PM - 7 PM peak window. Has anyone else seen Westar's billing system apply wrong TOU rates despite correct interval timestamps? This could be a $12,000+ annual overcharge for this manufacturing client.
Westar Energy TOU billing errors - interval data shows peak usage in off-peak hours
Bonnie, I've seen similar issues with MLGW here in Memphis, though not specifically Westar. Check if their billing system is using local time vs. standard time consistently. Sometimes the interval data is recorded in one time format but the TOU schedule is applied using another. Also verify if there are any seasonal adjustments that might be shifting the peak window. Have you contacted Westar's key accounts department directly?
This sounds like a classic time synchronization issue. APS here in Phoenix had problems a few years back where their AMI system wasn't properly accounting for daylight saving time transitions. The interval data timestamps were correct, but the TOU rate application was off by an hour for several months. Worth checking if the errors started around a DST transition date. Did you compare multiple months of data?
Sarah makes a great point about DST. I went back and checked - the errors definitely started in mid-March right after the spring time change. The interval data shows correct CST timestamps, but it looks like the billing system is still applying TOU rates as if it's standard time. Reggie, I haven't contacted key accounts yet but that's my next step. This is clearly a systemic issue, not just affecting my client.
We had almost identical situation with CPS Energy here in San Antonio about 18 months ago. Turned out their new AMI system was recording intervals correctly but the legacy billing system wasn't updated to handle the DST transition properly. CPS issued credits to affected customers once we brought it to their attention with solid interval data analysis. The key is having clean documentation showing the discrepancy between recorded usage time and billed TOU period.
Angela's right about documentation being crucial. Make sure you have screenshots of both the raw interval data and the billing detail. Ohio Edison has been pretty good about correcting these types of errors when presented with clear evidence. Also request the TOU rate schedule that was supposed to be applied and compare it line by line with what actually shows on the bill. Sometimes there are multiple rate schedules and they apply the wrong one.
Update: Westar acknowledged the DST billing error and issued a $14,200 credit to my client. They're also reviewing other large commercial accounts for the same issue. Thanks everyone for the suggestions - the time synchronization angle was exactly what I needed to focus on. Always helpful to know others have fought similar battles!