summary:
A Department of Energy study found that depending on which electrical utility region an electric or plug-in hybrid recharges from the carbon footprint of the electricity provider to generate the electricity could be more than the carbon footprint generated by a regular gas-electric hybrid like the Toyota Prius. The Western part of the USA, especially the Northwestern USA states, is where electric and plugin hybrids would generate less carbon dioxide emissions than a regular hybrid. However, in the Mid-Atlantic states and the Upper Midwest States, a regular hybrid like the Toyota Prius would have a smaller carbon foot print than an all-electric car like the Nissan Leaf. In New york, Ohio, Illinoise, and the Southeastern states a regular hybrid(like the Toyota Prius), would have a smaller carbon foot print than an all electric car (like the Nissan Leaf) OR a plugin hybrid (like the Chevy Volt).
analysis/commentary:
Carbon foot print cause by electricity used by a Plugin or All Electric vehicle is very low if the electricity is generated by hydroelectric, solar, geothermal or wind power. Electric power generated by nuclear power would have a radioactive waste foot print (which is not identified in the source story). The source story identifies electrical utility regions where electricity is mainly generated by using coal/natural gas/diesel (fossil fuels) inwhich the electricity used by a EV or PHEV would indirectly generate a carbon dioxide footprint.
source: The Dirty Truth about Plug-in Hybrids: How green is that electric car? Depends on where you plug in. Michael Moyer. Scientific American. July 2010. Vol. 303. Number 1. page 54-55