Working on a complex audit for a manufacturing client in New Orleans on Entergy's LGS rate schedule. Their interval data shows consistent usage during what should be off-peak hours, but Entergy is billing significant portions as on-peak. The rate schedule clearly states on-peak is weekdays 1 PM to 7 PM June through September, but I'm seeing weekend and late evening intervals classified as on-peak. This is costing them about $800/month in incorrect TOU charges. Has anyone else dealt with Entergy TOU classification errors?
Entergy TOU rate analysis - finding errors in peak period classifications
Juan, I've seen this with Oncor in Texas too. The issue is often in their billing system's holiday and weekend logic. Did you check if they're correctly handling holidays that fall on weekdays? Some utilities have bugs where holiday schedules don't properly override the standard weekday on-peak periods. Also verify they're using the correct time zone - I caught one utility billing Central Time customers using Eastern Time TOU periods.
This is classic billing system programming error territory. At TVA, we had a client where the utility's TOU logic was applying daylight saving time transitions incorrectly, creating phantom on-peak hours. I'd recommend pulling several months of interval data and creating a spreadsheet that maps every 15-minute interval to its proper TOU period according to the tariff. Then compare that to what they actually billed.
Albert, that's exactly what I did. Created a master TOU calendar for 2016-2017 and found systematic errors. Entergy was classifying some Saturday intervals as on-peak, particularly during summer months. They were also double-billing certain holiday periods. When I presented this analysis, they immediately acknowledged the billing system error. They're now going back 24 months to recalculate. Estimated refund is around $18,000.
Great work Juan! Idaho Power had similar issues with their TOU logic a few years back. The lesson here is that billing systems are only as good as their programming, and complex TOU schedules are error-prone. I always create my own TOU verification spreadsheet for major clients. It takes time upfront but catches these systematic errors that can cost thousands over time.
This thread is gold for TOU auditing techniques. In South Carolina, Santee Cooper has pretty straightforward TOU periods, but I've learned to never trust the utility's classification without verification. Juan's spreadsheet approach should be standard practice for all of us. The $18,000 recovery shows why interval data analysis is so valuable for our clients.
Working with Georgia Power's new TOU rates here in Atlanta, and their billing system has been glitchy since the rate changes took effect. I'm seeing similar weekend/holiday classification errors. The key is understanding that most utility billing systems use lookup tables for TOU periods, and those tables have to be manually updated for each rate change. Human error in those updates creates these systematic billing mistakes.
TEP in Arizona has had ongoing TOU issues since they implemented their new AMI system. The problem is that interval data collection and TOU classification happen in different systems, and the handoff between systems is where errors occur. I always request the raw interval data AND the TOU classification logs to verify they match. It's tedious work but catches expensive errors.
The more complex the TOU schedule, the more likely you'll find errors. MidAmerican's simple two-period TOU is pretty bulletproof, but utilities with four or five different TOU periods and seasonal variations are much more error-prone. Juan's case shows why we need to be just as analytical about time-of-use as we are about demand and consumption. Great detective work!
Thanks everyone for the feedback and validation. The client was thrilled with the $18,000 recovery, but more importantly, we've established a monitoring process to catch these TOU errors going forward. Entergy has also committed to fixing their billing system logic. This forum is invaluable for sharing these technical wins and methodologies.
Excellent case study Juan. This type of systematic TOU billing error is exactly why interval data analysis is becoming so critical in our industry. The fact that you recovered $18,000 and got them to fix their billing system shows the value of thorough forensic analysis. I'm going to reference this case in my next webinar on TOU auditing techniques. Great work by everyone who contributed to solving this puzzle.