Found what looks like a systematic error in Xcel Energy's demand charge calculations for one of my clients. They're on Schedule C&I and the demand charges don't match my manual calculations. Anyone else seeing issues with Xcel's billing system lately? The CT ratio is 400:5 and I'm seeing discrepancies of $1,200+ monthly.
Xcel Energy demand charge calculation error
Alice, the bills show 2,680 kW demand but my calculation based on the interval data shows maximum should be 2,345 kW. I've triple-checked the CT ratio and ratchet calculations. Something is definitely wrong.
Nancy, good point about the interval window. I was using 15-minute data but let me check if Xcel uses 30-minute for billing. The billing cycle vs calendar month is also worth investigating. Thanks for the suggestions.
Harvey, turns out it was the interval window issue Nancy mentioned. Xcel was using 30-minute intervals and I was calculating based on 15-minute peaks. Once I adjusted my calculation method, everything matched up perfectly. No billing error after all.
Good reminder for everyone - always verify the utility's demand measurement methodology before assuming billing errors. Different utilities use different interval windows, and some even use rolling intervals vs fixed time blocks. Pete, thanks for following up with the resolution.
Pete, that's a significant difference. Are you looking at the same demand window that Xcel uses? Some utilities use 15-minute intervals, others use 30-minute. Also check if they're using calendar months vs billing cycle periods.
Pete, what's the actual demand showing on the bills vs your calculations? Are you factoring in the ratchet provision correctly? Xcel's C&I schedule has some peculiar ratchet language that can be tricky.
Pete, I haven't seen systematic errors with Xcel but CT ratio mistakes are always possible. Have you verified the CT ratio on-site? Sometimes the billing records don't match the actual installation, especially after equipment upgrades.
Pete, any update on this? I'm starting an audit with a large Xcel customer and want to know if I should be looking for similar issues.