Dale H. from Indianapolis here. I'm drowning in AES Indiana TOU rate comparisons for a manufacturing client. They're looking at Schedule TOU-GSD-A vs Schedule IS-TOU and the seasonal demand charges are making my head spin. Does anyone have an Excel template that handles time-of-use rates with seasonal variations? Their load profile shifts dramatically between summer cooling and winter production schedules.
Excel model for comparing TOU rates - anyone have a template?
Jennifer R. in Sacramento. I built one for PG&E's crazy TOU schedules that might help. It handles up to 4 seasons and 6 time periods per day. Main trick is using INDEX/MATCH functions to pull the right rates based on month and hour. Can you share the specific rate structures you're comparing?
Jennifer R. - that sounds perfect! TOU-GSD-A has summer demand charges of $18.42/kW vs winter $12.85/kW, plus energy rates ranging from $0.0891/kWh off-peak to $0.1247/kWh on-peak summer. The IS-TOU is even more complex with intermediate seasons and coincident peak adjustments. Would love to see your template approach.
Craig P. from Portland Oregon. For seasonal complexity like that I use pivot tables feeding the calculations. Set up your load data with datetime stamps then pivot by month/hour to match rate periods. Works great for PGE's Schedule 32 TOU which has 5 different time periods.
Randy Dawson here. For AES Indiana specifically, watch out for their Transmission Cost Recovery factor that changes quarterly - it's not always obvious in the main tariff sheets. Also their coincident peak determination is based on PJM system peak, not local peak, which can throw off your demand charge calculations if you're not careful. I can share a template that handles Indiana's quirks if you're interested.
Brett H. in Kansas. Similar challenge here with Evergy's Schedule TOU-LGS. Randy D., would your template work for other utilities or is it AES-specific? I'm dealing with 3-part demand charges plus coincident peak adjustments that change monthly.
Brett H. - the core template is flexible enough for most TOU structures. Main difference is how utilities define peak periods and whether they use coincident vs non-coincident demand. For Evergy you'll need to account for their Regional Transmission Service charge that varies by month. I'll post a generic version on the resources page this weekend.
Randy D. and everyone - this has been incredibly helpful. Got the analysis done and client is saving about $23,000 annually by switching to IS-TOU despite the complexity. The coincident peak timing made all the difference. Thanks for steering me in the right direction!