Submitted by Darren Smith, Weekend Contributor
If you drive a fully electric car, hoping at least to benefit the environment by reducing carbon emissions, the location of your home can actually affect how carbon neutral your ride is.
Why is this significant? It depends on which electric utility provides service.
Compare two vehicles: The all-electric Tesla S; and the Toyota Prius hybrid, garaged in two neighboring cities: Bellevue, WA; and Seattle. The cities are separated by Lake Washington and a floating bridge. It is not about sunlight or cloud cover it is the utilities used.
It seems your zip code could dictate the environmental benefits more than might be expected.
Seattle residents use Seattle City Light. Bellevue residents have Puget Sound Energy. Seattle City Light receives approximately 1% of its energy derived from coal whereas Puget Sound Energy uses 20% coal derived energy sourced from a coal plant in Colstrip, Montana. The coal plant is dirty by comparison with other energy sources and according to Seattle newspaper “The Stranger” is the eighth largest producer of greenhouse gases in the United States. Puget Sound Energy has a twenty percent ownership position in the plant.
The percentage of coal sourced electricity of PSE nearly eliminates the environmental benefit of using a pure electric vehicle such as a Tesla, making its carbon footprint nearly identical to that of the hybrid gas/electric Toyota Prius.
A study by the Sightline Institute’s Clark Williams-Derry presents some rather sobering news about location and carbon neutrality. Using PSE’s 2012 emissions figures a Tesla Model S with an 85 kilowatt battery emits 0.50 pounds of “carbon dioxide equivalents” per mile, compared with 0.51 pounds per mile for a Toyota Prius C. (This assumes a 5 percent rate of energy loss between the power plant and your outlet; PSE did not provide its specific loss rate, but 5 percent is pretty average.) Williams-Derry believes: “Having a lot of coal in your generation mix significantly reduces the benefits of driving a Tesla.”
Across the water in Seattle, the Tesla becomes greatly better environmentally while obviously the Prius’ difference is none.
PSE for its part has made bona fide efforts in trying to embrace renewable energy, a promising work in Kittitas County with the Wild Horse Wind and Solar Facility that can generate up to 273 megawatts of clean, renewable energy. Yet, the company still sources 30% of its electricity from fossil fuels.
Despite the utilities’ power mix there still remains the possibility the individual electric vehicle owner may install solar panels for charging, but therein reveals the problem of capital outlay costs aside from tax credits and other government and utility reimbursements.
What is clear is the need to address the energy, carbon costs and other pollutants as often as possible. Even the environmental cost of lithium ion batteries exists. But when location can dictate carbon costs for the environmentally conscientious, having to factor in zip codes is a problem best eliminated.
By Darren Smith
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