Working on an audit in Topeka and running into an issue with Westar Energy's demand billing. When I add up the kW readings from their 15-minute interval data for each billing period, it doesn't match the demand charges on the bill. The interval peak shows 847 kW but they're billing for 892 kW demand. Is there some kind of adjustment factor I'm missing? Their tariff documentation isn't very clear on this.
Westar Energy demand calculations not matching interval totals
Floyd, check if they're using a demand ratchet or if there's a minimum demand provision in the rate schedule. Some utilities bill the higher of actual demand or a percentage of the previous 12-month peak. Also verify the billing period dates match exactly with your interval data range. A few days difference can change which 15-minute peak gets captured.
Jim, you were right about the ratchet clause. Found it buried in section 4.2 of their GS-2 tariff - they bill 80% of the highest demand from the previous 11 months if it exceeds the current month's peak. The 892 kW billing demand is actually from last August when they hit 1,115 kW during that heat wave. Thanks for pointing me in the right direction.