Leland Snook is Director, Rates & Rate Strategy, for Arizona Public Service Company.
PUF's Liz Stipnieks: What are some of the challenges and opportunities you saw in putting together APS's residential rates?
Leland Snook: APS has had a long history of more advanced rate design for residential customers. However, we just went through a major overhaul of that rate design. We had achieved a fifty percent adoption of advanced rates with our old rate design. But we also had a couple of versions.
We had a frozen version with on-peak hours of 9 a.m. to 9 p.m. We had a new series that was generally available with on-peak hours from 12 p.m. to 7 p.m. We had about forty percent of our customers on time-of-use rates with an energy-only component, and ten percent on a demand rate. There were demand and energy-only versions for each time period.
Our peak has shifted over time and is actually later in the day than those timeframes. So, we proposed a 3 p.m. to 8 p.m. timeframe for the on-peak period. That's Monday through Friday.
For residential customers, on the demand component, we only measure it in that on-peak window. We measure it over a one-hour period, versus fifteen minutes for our commercial customers, which is a little bit more forgiving design.