Electric Drive Vehicles Don't Reduce Emissions as Much as Expected

In the past, researchers believed that electric drive passenger vehicles (EDVs) could reduce emissions. Yet this latest study reveals that even a sharp increase in the use of EDVs by 2050 would not significantly reduce emissions of high-profile air pollutants such as carbon dioxide, sulfur dioxide or nitrogen oxides.

EDVs is a catch-all term that includes hybrid, plug-in hybrid and battery electric vehicles. These means of transportation have been touted as ways to help reduce emissions and curtail climate change. But it seems that they're not as effective as previously supposed.

"We wanted to see how important EDVs may be over the next 40 years in terms of their ability to reduce emissions," said Joseph DeCarolis, one of the researchers, in a news release. "We found that increasing the use of EDVs is not an effective way to produce large emissions reductions."

In order to find out how effective EDVs were, the scientists ran 108 different scenarios in a powerful energy systems models. In the end, they found that even if EDVs made up 42 percent of passenger vehicles in the U.S., there would be little or no reduction in the emission of key air pollutants.

"There are a number of reasons for this," said DeCarolis in a news release. "In part, it's because some of the benefits of EDVs are wiped out by higher emissions from power plants. Another factor is that passenger vehicles make up a relatively small share of total emissions, limiting the potential impact of EDVs in the first place. For example, passenger vehicles make up only 20 percent of carbon dioxide emissions. From a policy standpoint, this study tells us that it makes more sense to set emissions reductions goals, rather than promoting specific vehicle technologies with the idea that they'll solve the problem on their own."

The findings are published in the journal Environmental Science & Technology.