I'm auditing a large commercial client on Austin Energy's Schedule CLG rate and found some interesting discrepancies in their TOU billing. The interval data shows significant load during off-peak hours (10pm-6am) but they're being billed at on-peak rates for some of these intervals. Austin Energy's rate schedule clearly states off-peak is 10pm-6am Monday-Friday, but about 15% of their off-peak usage is getting billed at the $0.092/kWh on-peak rate instead of $0.048/kWh off-peak. Has anyone else seen TOU classification errors like this with Austin Energy? The client's billing is off by about $4,800/month because of this.
TOU rate analysis - finding errors in Austin Energy Schedule CLG
Vanessa, I've seen similar issues with CPS Energy here in San Antonio. Sometimes the utility's billing system doesn't properly account for holidays or daylight saving time transitions when classifying TOU periods. Are the misclassified intervals happening around specific dates or is it random? Also check if Austin Energy has any special holiday provisions in their tariff that might explain the discrepancy.
This could also be a demand response event issue. Down here with FPL, when they call a critical peak pricing event, it can override the normal TOU schedule and apply peak rates during what would normally be off-peak hours. Check Austin Energy's tariff for any demand response or critical peak provisions that might explain why off-peak hours are being billed at peak rates.
Angela and Beth - good thoughts. I checked the Austin Energy tariff and there are provisions for critical peak events, but none were called during the periods I'm seeing the billing errors. The misclassified intervals seem random - sometimes Tuesday at 11pm gets billed as peak, sometimes Thursday at 2am. No pattern related to holidays or DST transitions. I think this is just a straight-up billing system error.
Vanessa, have you looked at the actual meter timestamps vs. the billing system timestamps? PG&E had an issue last year where their billing system was applying Pacific Standard Time to intervals that were recorded in Pacific Daylight Time, causing a one-hour shift in TOU period classification. Even though no holidays were involved, the time zone confusion was randomly affecting certain billing cycles.
This reminds me of an issue we had with We Energies in Milwaukee. Their billing system was corrupted and randomly assigning peak rates to off-peak intervals. The only way we caught it was by doing a detailed interval-by-interval comparison of the usage data vs. the billing data. You might need to export both datasets and do a line-by-line comparison to identify all the affected intervals.
Linda, that's exactly what I ended up doing. Exported 12 months of interval data and billing data into Excel and found 1,847 intervals that were misclassified over the past year. Filed a formal complaint with Austin Energy including all the documentation. They're reviewing it now but initial response suggests they acknowledge there was a billing system error.
Great work Vanessa! Documentation is key with these TOU billing errors. When I had a similar case with PG&E in San Jose, they initially denied there was an error until I provided the detailed interval-by-interval analysis. Make sure you're asking for interest on the overcharges too - Austin Energy should compensate for the time value of money on those incorrect billings.
Pete's right about asking for interest. Eugene Water & Electric Board here in Oregon has a standard policy of paying 6% annual interest on billing errors once they're verified. Don't let Austin Energy just issue a credit - push for the full financial impact including interest and any late fees the customer might have incurred because of the inflated bills.
Update: Austin Energy agreed to the refund! They're issuing a $67,400 credit covering 14 months of TOU billing errors plus 4% annual interest. They also fixed the billing system bug that was causing the random misclassifications. The client is thrilled and it validates the importance of detailed interval data analysis on these complex TOU rate schedules.
Fantastic result Vanessa! $67K is a significant recovery. This case should be a reminder to everyone to never assume the utility's TOU billing is correct, especially on complex commercial rate schedules. The billing systems are only as good as their programming, and clearly Austin Energy had some bugs to work out.