Researchers from the University of Texas and the Massachusetts Institute of Technology in the U.S. conducted a study on the Plug-in Hybrid Electric Vehicles (PHEVs) to determine the optimum way to charge these vehicles.
PHEVs have become popular due to their increased efficiency, less detrimental impact on the environment and lower cost of fuel. These electric vehicles can run on both gasoline and on battery power, and do not release any pollutants when they run on battery. But, the electricity generating units (EGUs), which are used to charge these batteries, emit pollutants.
The researchers studied three different charging situations – charging at off-peak hours during the night, charging with the necessary amount of charge just before the trip to maximize battery life, and thirdly, charging at times suitable for the driver.
Emissions associated with EGUs were found to be lesser than gasoline related emissions. Night time charging was associated with the least amount of ozone emission leading to positive air quality. Nitrogen oxides emitted at night would get diluted before sunrise and would not be able to react with sunlight to form harmful pollutants. The results of the study about charging PHEVs at night time were published in Environmental Research Letters, a journal published by IOP.
Encouraging vehicle charging during night times would help the air quality and improve the reliability of the electricity grid.
Source: http://iopscience.iop.org/