Nancy P. from Spokane. I've been building an Excel model to compare Avista's Schedule 25 TOU rates against their standard Schedule 21 for commercial customers. The TOU has peak hours 6AM-10PM weekdays with different summer/winter periods. Anyone have a good template or approach for modeling the hourly usage patterns? I'm struggling with how to estimate the peak vs off-peak splits without detailed interval data.
Excel model for comparing time-of-use vs standard rates
Walt D. in Pittsburgh here. For TOU modeling without interval data, I use a rule of thumb based on business type. Office buildings typically see 75-80% of usage during peak hours. Manufacturing depends on shift patterns but often 60-65% peak. Retail is usually 70-75% peak. You can refine these with the customer's operating schedule.
Randy Dawson here. Walt's percentages are good starting points. For your Excel model Nancy, I recommend setting up separate worksheets for each rate schedule, then use lookup tables for the time-of-use periods. Don't forget Avista's demand charges - Schedule 25 has separate peak and off-peak demand billing which can significantly impact the analysis. Also include their Power Cost Adjustment (PCA) rider which updates quarterly. The TOU benefits really depend on the customer's load profile flexibility.
Larry N. also in Spokane. Nancy, if you're working with Avista customers regularly, you might want to request interval data directly from them. Avista usually provides 12 months of 15-minute data for commercial accounts upon request. Makes the TOU analysis much more accurate than estimating usage patterns.
Great suggestions everyone. Randy, I hadn't considered the separate demand billing on Schedule 25 - that's a key factor. Larry, I didn't know Avista would provide interval data on request. That would make this so much easier. What department do you usually contact for that?
For interval data requests, call Avista's Commercial Energy Services at 509-495-4500. Ask for the Key Accounts team. They usually need a signed data release form from the customer but turnaround is pretty quick - about 3-5 business days.
Lisa F. from Arlington. This thread is super helpful. I'm dealing with similar TOU vs standard rate comparisons with Oncor here in Texas. The ERCOT market adds complexity with all the pass-through charges, but the modeling approach should be similar. Nancy, would you be willing to share your Excel template once you get it working?
Lisa, I'll work on cleaning up the model and can share a generic version. The Avista-specific riders won't apply to Texas but the basic TOU comparison structure should work. Give me a few weeks to get it polished.
Nancy, any update on that Excel model? I've got three TOU analyses coming up and could really use a good template to work from.