This sounds a lot like demand-billing [1] [2] that's common with electric utilities, particularly commercial, and increasingly, people with grid-tied solar installations. [citation needed]
You pay a lower per-kilowatt-hour rate, but your demand rate for the entire month is based on the highest 15-minute average in the entire month, then applied to the entire month.
You can easily double or triple your electric bill with only 15 minutes of full-power usage.
I once got a demand bill from the power company that indicated a load that was 3 times the capacity of my circuit (1800 amps on a 600 amp service). It took me several days to get through to a representative that understood why that was not possible.
You pay a lower per-kilowatt-hour rate, but your demand rate for the entire month is based on the highest 15-minute average in the entire month, then applied to the entire month.
You can easily double or triple your electric bill with only 15 minutes of full-power usage.
I once got a demand bill from the power company that indicated a load that was 3 times the capacity of my circuit (1800 amps on a 600 amp service). It took me several days to get through to a representative that understood why that was not possible.
[1] http://www.stem.com/resources/learning
[2] http://www.askoncor.com/EN/Pages/FAQs/Billing-and-Rates-8.as...