Major headache with APS after client installed solar. Manufacturing facility in Tempe, 2MW rooftop system went live in January. APS moved them from E-32 Large General Service to E-65 Customer Generation tariff. Problem is they're being charged standby charges of $8.50/kW on their entire demand, not just the solar capacity. That's an extra $34,000/month! Tariff language is murky - anyone dealt with this?
Arizona manufacturing client installed 2MW rooftop solar - APS billing suddenly wrong
Sarah - APS standby charges should only apply to the nameplate capacity of the solar system, not total facility demand. E-65 Schedule clearly states "applicable to the Customer Generation System capacity." You need to file a formal complaint. I've seen this exact error before.
Mike's right. Had similar issue with TEP in Tucson last year. They tried charging standby on full facility load instead of just the 1.5MW solar array. Took 3 months and a complaint to Arizona Corporation Commission to get it fixed. Refund was $127,000.
Thanks both. Filed the complaint yesterday. APS claims their billing system automatically applies standby to total demand when customer generation is present. That's clearly wrong but they won't budge without ACC intervention.
Document everything! Screenshot the tariff language. APS has been doing this "accidentally" to several solar customers. Class action might be warranted if the pattern continues.
Solar interconnection billing errors are becoming more common as utilities struggle with outdated billing systems. Always verify that standby/interconnection charges match the actual generation capacity, not facility demand. Most state PUCs have clear guidance on proper application of these charges.