October 2, 2015 – Apparently, public charging infrastructure is not needed everywhere to enable PEV (plug-in electric vehicle) adoption. Instead, infrastructure should be focused at homes, workplaces and public hot spots that serve multiple venues.

This conclusion stems from Idaho National Laboratory (INL), which recently reported analysis results from what it calls the largest collection of light-duty PEV and charging infrastructure demonstrations in the world. The findings will be used to support and refine activities of the U.S. Department of Energy’s (DoE) EV Everywhere Grand Challenge.

A commonly cited barrier to greater adoption of PEVs is the lack of public places for drivers to plug in their vehicles. To tackle this barrier, researchers sought to understand how many and what kind of charging stations are needed; where and how often do PEV drivers charge, etc.

In 2009, DoE set out to answer these questions. Several resulting projects (Charge Point America project, Chrysler Ram PEV Demonstration, General Motors Volt Demonstration, South Coast Air Quality Management District/Via Motors PHEV Demonstration, and The EV Project) installed roughly 17,000 charging stations and deployed about 8700 PEVs across the U.S. The DoE Office of Energy Efficiency & Renewable Energy provided half the funding for the five projects, and INL researchers collected and analyzed the resulting data.

Data collected from all five projects captured nearly 130 million miles of driving and 6 million charging events, providing “the most comprehensive view of PEV and charging usage to date”.

The analysis reveals that PEV private owners performed an average of more than 85% of charging at home. When away from home, they tended to favour just a few public charging stations, with workplace stations being most popular and less expensive to install. Factors that drive the popularity of public charging locations are community-specific.

The study also finds that drivers adjust their charging habits based on conditions such as fees and rules for use. When privately owned Volts are charged frequently, they achieved better than 120 mpg in normal consumer use patterns. Also, workplace charging was found to enable significant electric range extension. Project participants with access to charging at work were observed to drive 25% more on electricity alone than the overall group of vehicles in the project.