This report from the Smart Electric Power Alliance (SEPA) and their partners explores how utilities can influence home charging behavior through EV time-varying rates that provide an incentive to residential customers to charge off-peak, thereby minimizing distribution system impacts and avoiding the need for costly infrastructure upgrades and investments. Specifically, the report analyzes residential EV time-varying rates based on survey results from customers and utilities and identifies factors that increase rate enrollment. For the purposes of this report, residential time-varying rates were included that were identified and marketed as rates specifically available to EV drivers. To collect insights on residential EV time-varying rates implemented to date, SEPA worked with The Brattle Group to develop and administer a survey for U.S. utilities that had a qualified rate in-place for at least one year. In addition, to collect insights from EV drivers on time-varying rates, SEPA co-developed a survey with Enel X which was distributed nationwide to the company’s JuiceNet-enabled charging station customers.
The survey results show that customers on an EV-specific time-varying rate were more familiar with the rate rules and more likely to charge off-peak compared to their generic time-varying rate counterparts. SEPA also found that utility-driven initiatives had significantly higher average enrollment than mandated programs and that utilities that actively market residential EV rates had customer enrollment 1.4 times greater than those that were not marketed. Furthermore, 72 percent of the non-enrolled customers indicated that they were willing and able to charge their EV during off-peak hours if the rate resulted in savings and was convenient to use.