Tony V. in Newark. I'm building an Excel model to compare PSE&G's standard GP rate against their new TOU-GP time-of-use schedule. The challenge is modeling the seasonal rate periods and peak/off-peak hours that change throughout the year. Has anyone built something similar that accounts for summer vs winter pricing periods? My client has fairly consistent 24/7 load but I need to show potential savings across different consumption patterns.
Time-of-Use Rate Comparison Model
Randy here. TOU modeling gets complex fast, especially with seasonal variations. I built a monthly model that breaks down hourly consumption by rate period. Key is getting good interval data from your client's meter - at least 12 months to capture seasonal patterns. PSE&G's TOU-GP has different peak hours in summer (1-7 PM) vs winter (6-9 AM and 6-9 PM weekdays). You need separate calculations for each month. What's the client's load profile look like?
Carla N. in Cincinnati. We use a pivot table approach with 8760 hours of data when available. Import the interval data, tag each hour with the appropriate rate period, then sum by month and rate category. Duke Energy Ohio's TOU rates change peak hours seasonally too. The pivot table method lets you quickly model different scenarios and rate structures.
Randy, the client runs a small data center so pretty flat load profile around 85-90 kW continuous. Load factor is about 92% so most hours are near peak demand. That might actually hurt them on TOU since they can't shift much load to off-peak periods. Carla, I like the pivot table idea but I only have monthly billing data right now. Think it's worth requesting interval data from PSE&G?
Gary W. in Tacoma. Data centers usually don't benefit from TOU rates unless they can shift cooling loads or have backup generation for peak periods. Puget Sound Energy has similar issues with their Schedule 40 TOU. With 92% load factor your client is probably better off on standard rates. But definitely get the interval data - it's free from PSE&G and invaluable for analysis.
Gary's right about data centers and TOU. With that high load factor, your client is consuming power during all rate periods proportionally. TOU rates reward customers who can shift load to off-peak hours. A 90 kW continuous load will hit peak rates every day. I'd model it anyway to confirm, but standard GP rate is probably better. The interval data request is definitely worth it for future analysis.
Mike S. in Boise. Idaho Power has a TOU option that actually penalizes high load factor customers exactly like what you're describing. Sometimes the standard rate is the right answer. I always run both scenarios even when I suspect the outcome. Clients appreciate seeing the numbers rather than just taking our word for it.
Thanks everyone. I'm going to request the interval data and build the model anyway. Even if TOU doesn't work for this client, I'll have a good template for future analysis. Gary and Randy, your point about load shifting capability makes perfect sense. Data centers are tough candidates for TOU unless they have some flexibility I'm missing.
Janet A. in Tacoma. One thing to consider - some data centers can shift backup testing and maintenance to off-peak hours. It's not much load but every bit helps on TOU rates. Also check if PSE&G has any demand response programs that could offset the TOU disadvantage. Puget Sound has some good DR options for data centers.
Janet, good point about maintenance scheduling. This client does monthly generator testing that could be shifted to off-peak. It's only about 2 hours but worth modeling. I'll look into PSE&G's demand response options too. Sometimes the DR payments can tip the economics in favor of TOU rates.