A Million New Vehicles, but Unknown Emissions Savings

Three things for you to think about:

1)   During his 2011 State of the Union address, President Obama announced that the U.S. aims to have one million “advanced technology” vehicles on the road by 2015.

2)   Advanced technology cars are electric or hybrid electric vehicles that don’t run solely off a traditional combustion engine. They are expected to emit less carbon dioxide than regular cars if the electricity does not come from coal power.

3)   A new report from MIT says that the technology to reduce vehicle emissions is ready and waiting to make a difference — but building the infrastructure to support the technology is a tough task.

The debrief:

For the United States, there are plenty of benefits to ramping up the production of “advanced technology” cars, which are cars without plain old combustion engines. According to the Department of Energy, producing hundreds of thousands of these vehicles would stimulate the economy and create new jobs. And because the cars don’t rely entirely on petroleum-based fuels like gasoline and diesel, switching to hybrid and electric cars means the country may not have to rely as much on other nations for transportation fuel. Policy makers are also often quick to mention that advanced technology cars can help lower U.S. greenhouse gas emissions.

A Toyota Prius hybrid plug-in vehicle, plugged in and charging. Credit: Tom Rafferty/flickr.

But according to a new analysis from MIT’s Energy Initiative, just bringing on new and cleaner burning vehicles won’t be enough to lower emissions; an overhaul of electrical infrastructure will also be needed to make a big dent. Based on a symposium held at MIT in the spring of 2010, the new report says some types of electric cars actually emit more carbon dioxide (CO2) than conventional hybrid cars that consume some gasoline. Only by vastly expanding the availability of carbon-free electricity, like that coming from nuclear power or biomass, can electric vehicles make a big difference in CO2 emissions. 

The thing about “advanced tech” cars is that they rely, in part or in whole, on electricity for power. Battery electric cars, like the Nissan Leaf and the Chevy Volt, and plug-in hybrids that all draw some electricity from a plug in the wall can only be considered as clean as their original source of electricity. So, when electricity going into the car originates at a coal-burning power plant, the CO2 that is belching out of the smokestacks counts just the same as if it were running out of a tailpipe. 

The MIT report says that conventional hybrids, like the Toyota Prius, which burn some gasoline and generate their own electricity, reduce CO2 emissions by 33 percent compared to an average car that uses an internal combustion engine. On the other hand, plug-in hybrid vehicles have about 66 percent lower emissions — but only if the electricity is “carbon-free,” which means it isn't coming from any of the coal-fired plants that provide about half of the country's energy today. If the electricity is derived from coal, researchers say the electric vehicles are only slightly better than regular gas-powered cars.

Why this science matters:

There’s no doubt that the expected roll-out of more advanced technology cars by 2015 would have job creation and energy security benefits. In addition, there are some potential environmental gains as well. The cars, vans and small trucks that Americans drive every day are responsible for nearly 20 percent of the country’s total CO2 emissions, according to MIT’s “Electrification of the Transportation System” report. So if cars can somehow become cleaner burning, that would go a long way towards lowering the country's overall emissions.

There is a hiccup when it comes to electric vehicles that draw energy from an electricity source that produces large amounts of CO2, however. With more electricity needed to power new vehicles on the road, electric utilities will have to work even harder. If fossil fuels (especially coal, which is more carbon-intensive) are the source of energy for the extra electricity produced, CO2 emissions may end up increasing, not decreasing. The researchers at MIT recommend that along with new vehicles must come an updated electrical grid with more carbon-free power.