Been doing this for about 18 months now and almost blew a huge recovery because I didn't understand ComEd's ratchet provision in Rate 6L. Client had a transformer failure that spiked their demand to 2,800 kW for one month, then their ratchet kicked in at 90% for the next 11 months. I was looking at the individual monthly bills and thinking the demand charges looked reasonable for their usage pattern. Almost signed off on 'no issues found' until my supervisor asked me to walk through the ratchet calculation manually. Turned out they were being billed correctly but should have been on a different rate schedule entirely. We recovered $183,000 in overcharges going back 4 years. Anyone else have stories about nearly missing the big ones due to inexperience?
Nearly missed $180k on ComEd demand ratchet - my rookie mistake
Oh man, we've all been there. My first year I spent three weeks analyzing an Oncor account thinking there were massive errors in their power factor penalties. Kept running the calculations over and over because the numbers seemed too high. Finally realized I was using the wrong tariff sheet - they'd been moved to a new rate two years prior and I was working off the old schedule. No overcharge at all, just me not doing my homework on rate history. Cost the firm about 60 billable hours. Lesson learned: always verify current rate schedules and effective dates before diving into the analysis.
Good catch by your supervisor, Yuri. Here in Connecticut with Eversource, I made a similar error early on with their coincident peak program. Spent weeks calculating what I thought were billing errors on transmission charges, turns out I didn't understand their load profiling methodology. The client's demand wasn't hitting during the actual ISO-NE system peaks, so the charges were correct. Always document your methodology and have someone else review it before presenting findings. Saved me from several embarrassing client meetings over the years.
Duke Energy here in Charlotte - made a whopper of a mistake on a Schedule LGS account where I calculated $240k in demand charge errors. Presented it to the client, they got all excited, then Duke's rep politely explained that I had misunderstood their ratchet reset provision. Apparently if you go 12 consecutive months below 50% of your contract demand, the ratchet resets. This client had done exactly that but I missed it in the tariff language. No overcharge existed. Client wasn't happy about getting their hopes up. Now I read every single tariff provision three times and highlight anything related to ratchets, resets, or special conditions.
Rocky Mountain Power territory here. Similar story with a manufacturing client where I thought I found $95k in power factor penalty overcharges. Spent two weeks building spreadsheets showing how their PF was above 0.9 every month. Turns out RMP calculates penalties based on the lowest 15-minute interval each month, not the monthly average. I was using the wrong calculation method entirely. The penalties were all legitimate. Client understood, but it was a humbling experience. Always make sure you understand exactly how each utility calculates every component before claiming errors.
Ameren Missouri - thought I had a slam dunk case on coincident billing where the utility was allegedly double-billing demand charges. Worked up a whole presentation showing $156k in overcharges over 3 years. Day before the meeting with Ameren, I decided to call their commercial billing department to confirm my understanding of their CP calculation. Turns out there's a specific provision in Schedule LGS that I completely missed. When a customer's individual peak doesn't align with the system peak by more than 20%, they use a blended calculation. The bills were right, my analysis was wrong. Lesson: when in doubt, call the utility first and ask questions.
Thanks everyone for sharing your stories. Makes me feel less stupid about my mistake. @Pam your point about calling the utility is gold - I've started doing that more often and it's saved me from several wild goose chases. The ComEd reps are usually pretty helpful if you ask specific technical questions. I think the key takeaway is that confidence in this business comes from making these mistakes and learning from them. Better to catch them ourselves than have the client or utility catch them for us.