Found a nasty one on an Ohio Edison TOU account. The client is a plastics manufacturer in Akron who switched to a TOU rate in 2011 to take advantage of their overnight production schedule. At the time, the on-peak period was 2 PM to 7 PM weekdays. Ohio Edison changed the peak period to 12 PM to 8 PM in a 2013 rate case. Nobody notified existing TOU customers. My client's afternoon shift now runs right through peak hours. The rate that was saving them $2,800/month in 2011 has been costing them $1,600/month MORE than the flat rate since 2013. That's 14 months of overpayment before I caught it — about $22,400.
Client on TOU rate — peak period definition changed and nobody told them
This is a perfect example of why you need to re-audit clients periodically, not just once. Tariff changes can turn a good rate into a bad rate overnight. I recommend re-checking every TOU client at least once a year, and always after a rate case. The peak/off-peak window shift is one of the most common TOU errors I see.
Excellent catch. When a utility changes peak period definitions during a rate case, they're required to notify the PUC but not necessarily individual customers. The burden falls on the customer — or their auditor — to track tariff changes. This is why I tell every auditor to set a calendar reminder after every rate case: pull the new tariff and check every client account against the updated provisions. The 30 minutes it takes to review changes can prevent months of overpayment.
I had the exact same thing happen with a bakery on Georgia Power. They shifted to overnight baking specifically for TOU savings, then Georgia Power moved the peak window and nobody noticed for two years. Painful.
Switched the client back to the flat rate and filed for a refund of the overpayment since the peak period change. Ohio Edison is pushing back, saying the customer was responsible for monitoring tariff changes. Escalating to PUCO. Will update.