New research from N.C. State professors suggests that the increased production and use of electric cars might not actually reduce harmful emissions.
In fact, the N.C. State professors argue that the use of hybrid vehicles, electric vehicles and battery electric vehicles won’t significantly reduce levels of carbon dioxide, sulfur dioxide or nitrogen oxides.
Electric drive vehicles and alternative energies and fuels are being researched to help stem the rising tide of emissions. President Barack Obama encouraged the Department of Energy to enact policies that would promote EDVs. These policies include tax credits and millions of dollars in funding.
Though this research puts a dent in the validity of these plans, the N.C. State researchers said it doesn’t discourage the current progress being made, but simply suggested that reducing emissions will require a more holistic approach.
Joseph DeCarolis, an assistant professor of civil, construction and environmental engineering, authored the paper with graduate student and research assistant Samaneh Babaee and former postdoctoral research assistant Ajay S. Nagpure.
They examined five factors on future development of electric cars, including crude oil and natural gas prices, federal CO2 policy, a federal renewable portfolio standard and EDV battery costs. All of these were combined in analysis to form 108 scenarios that encompassed numerous possible outcomes for the future of electric cars.
In addition, the researchers used an energy-system model that measured the economic presence of EDVs in the U.S. market and changes this would have on CO2, SO2 and NOx emissions. Rather than simply projecting what the energy distribution would be in the future, they were able to quantify it with greater accuracy to the year 2050, and thus derive the effects on emissions from the given data.
The subsets of the model included a Model Generator using The Integrated MARKAL-EFOM System and the National U.S. TIMES Data Set. All five factors were used in this model, which optimized the multitudes of data simultaneously.
The results varied according to which of the five variables were modified and in what sequence. Having caps for CO2 emissions would affect the EDV projection or future gas prices would adversely affect it. Taking all these fluctuating variables into account, the results demonstrated that overall changes in emissions were not significant.
“There are a number of reasons for this,” DeCarolis said. “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.”
DeCarolis said federal policy should emphasize reducing emissions as opposed to stressing specific technologies, such as cars.
“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,” DeCarolis said.
DeCarolis also said certain caveats to the results found. For one, the research didn’t take into consideration the potential effects of relocating dense urban emissions from cars to more remote power plants, whose emissions can be more easily monitored and reduced. Another stipulation was the assumption that electric cars would be charged constantly throughout the day. Consumer choice and buying patterns could be a barrier to the development and expansion of electric cars.
