Got a client here in San Antonio on CPS Energy's large commercial rate and their demand ratchet calculations don't seem right. The tariff states 80% of highest demand in previous 11 months, but when I analyze their interval data, I'm getting different numbers than what CPS is billing. Their interval data shows peak demands that should create lower ratchet levels, but the bills show higher ratchet amounts. Has anyone else had issues with CPS Energy demand ratchet calculations? I'm missing something or they are.
CPS Energy demand ratchet calculations seem off - need help with load profile analysis
Angela, are you sure you're looking at the right demand values? Some utilities use different demand measurements for ratchet calculations - like using the billing demand (which might include power factor adjustments) rather than the raw kW demand from interval data. Also check if CPS Energy uses a different methodology for determining the "highest demand" - some utilities look at the highest single interval, others use averaged values over multiple intervals.
I work with TEP in Arizona and they have a similar 80% ratchet provision. The key thing to watch for is whether they're using coincident demand (your actual peak during the utility's system peak hour) versus non-coincident demand (your highest individual demand regardless of when it occurs). Also verify the 11-month lookback period - make sure they're not including estimated billing periods or partial months in the calculation. These details can significantly impact the ratchet amount.