Study finds that drivers will charge off-peak if it saves them money

A two-year study that examined the charging behavior of 142 households with plug-in vehicles. The PHEVs averaged 68 mpg and used 27 megawatt-hours of electricity.

 

The University of Colorado Boulder’s Renewable and Sustainable Energy Institute (RASEI) has presented the findings from a two-year study that examined the charging behavior of 142 households with plug-in vehicles. Partner Xcel Energy installed smart plugs in the participants’ garages, and Toyota loaned each household a Prius Plug-in Hybrid for one nine-week period.

Half the households were assigned to an “unmanaged” charging scenario, which allowed them to charge their cars at any time of day. The other half were assigned to a “managed” scenario, which allowed charging only from 10 pm to 6 am. Half of the households had time-of-use electricity rates, and the other half had a uniform rate. According to RASEI, most of those with standard electricity rates preferred the “unmanaged” scenario, and most of those with time-of-use rates preferred the “managed” scenario.

Households had access to two websites that provided data on vehicle electricity consumption and overall household electricity use. 90 percent of the households looked at the websites only a few times. Some never looked at the websites.

The PHEVs averaged 68 mpg, and were used for an average of 3.2 trips per day. Altogether, the cars used 27 megawatt-hours of electricity. It was less expensive to drive on electricity as a fuel than gasoline, even when paying higher on-peak electricity rates, according to an Xcel Energy analysis.

“The RASEI study demonstrates the importance of testing new technologies with real customers in everyday circumstances,” said Toyota spokesman Bill Reinert. “The results are often unexpected but help us understand the needs of potential customers and how to successfully introduce advanced technologies to the market.”

 

Source: University of Colorado Boulder