The Institute of Physics has published a study that suggests the best time to charge electric vehicles, in terms of impact to air quality, is at night. While electric vehicles do not produce emissions, electricity generating units do, a lot. Researches from the Massachusetts Institute of Technology (MIT) and the University of Texas have specifically been studying ozone pollutants under three different charging scenarios in Texas for plug-in hybrid vehicles.

The first scenario was based on charging cars at off-peak times during the night, the second under the conditions of maximizing battery life by charging vehicles just before use and only enough to complete the journey, and the third by charging the vehicles just after use.

electric vehicle charging station
image via GM

The study found that overall, across all cities and hours tested, the least amount of harmful emissions occurred at night, especially because the sunlight wasn’t around to interact with the particles. The eleven-page report is available for PDF download on the Institute of Physics website.

With more and more smart-meter programs being rolled out, night may be the best time in terms of electricity rates as well. But as we recently reported, not only are consumers largely unknowledgeable about the smart grid, but the infrastructure itself may not be ready for the large scale implementation of electric vehicles.

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