State may not see electric car emission benefits
Hybrid and other high-mileage, gasoline-powered vehicles driven in Colorado may produce fewer greenhouse gas emissions than all-electric vehicles such as the Chevy Volt or Nissan Leaf, according to a report released Tuesday.
The report, from the climate-research organization Climate Central, analyzed the “climate-friendliness” of different cars in different states based on the sources of power generation in those states.
In Colorado, where about 70 percent of power comes from coal — whose greenhouse gas emissions are a significant contributor to climate change — charging an electric vehicle from the power grid can result in more emissions than getting high mileage on a tank of gas, as hybrids do.
Electric vehicles are still the least-polluting options in states where renewables, hydroelectric or natural gas account for the majority of the power generated in the state.
A report from the advocacy group Union of Concerned Scientists, released last week, came to similar conclusions.
That report found nearly half of Americans live in regions where charging an electric vehicle on the grid “emits less global warming pollution than driving even the best hybrids,” though Coloradans and most Midwesterners driving electric vehicles would generate emissions equivalent to driving a vehicle that gets only 31 to 40 miles per gallon.
Both reports emphasize electric vehicles are still far better for the climate, environment and human health — in every region — than the average gas-powered vehicle.
“Our findings don’t mean that we won’t need electric cars as an option for fighting climate change,” said Eric Larson, a research engineer at Princeton University and senior scientist at Climate Central, who was the lead author of the report. “In the long term, electric cars may be the cornerstone of personal mobility in a world where carbon emissions are next to zero, which will be required to stabilize the climate.”
Some experts question the assumptions behind these reports, namely that it is possible to break down power generation by state or region while ignoring the time of day at which electric vehicles are charged.
Many power grids cross state lines, so that if you are in Washington, where most power comes from hydroelectric, at a certain time of day you might actually be getting power from Wyoming, where 90 percent of power comes from coal, pointed out Nick Nigro, manager of transportation initiatives at the Center for Climate and Energy Solutions.
These sorts of state-based breakdowns, he said, “are just not gonna be accurate. States import and export electricity at all times of the day.”
What would be most useful, Nigro said, is a report breaking down vehicle emissions by both state and time of day. Consumers might then be able to choose the time of day to charge their cars based on the source of power being used, and thus reduce the greenhouse gas emissions generated by their vehicle use.
Despite these asterisks, the conclusions of Tuesday’s report generally hold true in the case of Colorado because the power grid that serves the state only stretches to eastern Wyoming and parts of Nebraska, New Mexico and South Dakota, which, aside from South Dakota, all rely heavily on coal power.
The report finds the Toyota Prius is the best car for Coloradans concerned about their vehicle’s climate impacts, followed by the Honda Civic Hybrid. The Volt comes in eighth and the Leaf 11th.
This article is part of a grant-funded project in cooperation with Colorado Mesa University to report on issues of environmental concern.