Study says electric rates govern PHV charging, not online feedback


By: SGN Staff

Households with plug-in hybrid vehicles (PHVs) and smart meters "actively managed" their vehicle based on electricity rates, but largely ignored online feedback designed to help them make decisions, a study from the University of Colorado Boulder discovered.


The smart grid-related study, conducted by the university's Renewable and Sustainable Energy Institute (RASEI), took two years and involved 142 households equipped with smart meters. Toyota, the study sponsor, loaned 28 Prius PHVs and Xcel Energy installed smart plugs in study household garages. Participants shared the cars, each using them for nine weeks.


Two Web sites were made available to the participants, one operating as an almost instantaneous meter for vehicle power use when it was plugged in; and the other provided feedback on all household electricity consumption. They also were given the option of using unmanaged charging (charging whenever they wanted to) and managed charging (the cars were programmed to charge only between 10 PM and 6 AM), and were allowed to switch back and forth at any time.


Here are some of the study's preliminary findings:

·         About 90% of the households looked at the Web sites rarely, and some not at all.

·         Not surprisingly, most of the households paying standard electric rates preferred to charge whenever they wanted to and those with time-of-use rates preferred the managed "set-it-and-forget-it" approach (although many thought managed charging was inconvenient).

·         While electricity pricing was the strongest influence on charging decisions, time/cost and convenience also were considered important.

·         Households were generally well-satisfied with the PHVs they drove, but not their short range