A Survey of Residential Time-Of-Use (TOU) Rates

This presentation surveys TOU rate offerings in North America and abroad. It is organized into two sections:

Key findings:

The survey of residential TOU rates in the United States
- 14% of all US utilities offer a residential TOU rate; roughly half of IOUs offer one
- Where TOU is available, around 3% of customers are enrolled on average
- APS has the highest enrollment, with 51% of its residential customers on a TOU rate
- 74% of TOU rates have only two pricing periods
- 71% of TOU rates have a price ratio of at least 2-to-1
- Half of TOU rates have a price differential of at least 10 cents/kWh
- Of the utilities offering TOU rates, roughly half offer more than one TOU option
Emerging trends
- To address solar PV integration challenges, new TOU rates are being introduced with a low mid-day price and a peak period that is delayed until later in the evening
- A few utilities have recently introduced TOU rates on a default (i.e., opt-out) basis for all residential customers
- Volumetric TOU rates are increasingly being proposed by environmental advocates to address grid cost recovery issues associated with rooftop PV adoption (as an alternative to fixed charges or demand charges)
- TOU rates continue to be piloted in North America and internationally; the pilots consistently find that on average customers shift consumption from peak periods to off-peak periods