Energy Questions Answered
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EVs and The Environment   Arrow divider image - marks separation between nested pages that are listed as breadcrumbs.

One of the main reasons consumers are interested in electric vehicles is the fact that while in electric mode there are no tailpipe emissions. It should be noted, however, that electricity from the grid used to charge the batteries is primarily produced from fossil-fuel burning power plants that do emit greenhouse gases.

Based on emissions data from the National Renewable Energy Laboratory and a conservative set of assumptions*, electric vehicles charged using Colorado’s electric grid would emit less CO2 equivalent than a new, average light duty vehicle traveling the same number of miles per day when accounting for both tailpipe and charging-based emissions. At any range, battery electric vehicles would reduce emissions by 30%. Because plug-in hybrids use gasoline as well as electric components, they would reduce emissions by 30% up to their electric-only range and by lesser amounts above that range. At 60 miles per day, for instance, a plug-in hybrid may reduce emissions by 15% compared to a new conventional gasoline vehicle.

As Colorado uses a greater percentage of renewable energy in its electricity portfolio, CO2e emissions from electric vehicle charging will decrease. It should be noted, however, that the carbon intensity of the grid varies according to the time of day. Pulling electricity from the grid at night could mean you’re charging with higher percentages of coal and wind, whereas charging during the day might mean you’re charging with higher percentages of natural gas, coal, and solar.

Another environmental consideration for electric vehicle use is that these vehicles are relatively new to the U.S. auto market and only a small number of them have approached the end of their useful lives. As a result, few post-consumer batteries from electric vehicles are available, thus limiting the extent of battery-recycling infrastructure. As electric drive vehicles become increasingly common, the battery-recycling market will likely expand.

*Assumptions:
Plug-in hybrid can travel 30 miles before switching to gasoline
Plug-in hybrid achieves 37 mpg after switching to gasoline
New non-electric vehicle rated at 33.7 miles/gallon
19.6 lbs. of CO2e emitted/gallon of gasoline
1.0 lbs. of CO2e emitted/kWh
Mileage converted to electricity consumption at a rate of 0.37 ACkWh/mile
Daily charging