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John Shore
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Here and elsewhere, Mr. Bullis strongly disagrees with our decision to measure vehicle efficiency based on the amount of energy delivered to the vehicle at the pump (or plug). Very simply, we chose MPGe as a pump/plug-to-wheels efficiency measure for two reasons: (1) We wanted to have a simple and unambiguous efficiency measure that depends only on the vehicle, and not on any aspects of fuel production and distribution. (2) Upstream (wells to pump/plug) issues are addressed directly and indirectly in our second figure of merit – the cap of 200 g/mi on total wells-to-wheels greenhouse gas emissions. It was clear from the outset that – compared to gasoline vehicles - electric vehicles would have an easier time achieving 100 MPGe, but a harder time achieving 200 g/mi GHG emissions. Some argued that the competition unfairly favored electric vehicles, but we felt that the balance was reasonable. There’s no “right answer”, and one can continue to disagree about this. However, note that not a single electric vehicle made it to the validation stage in the Mainstream Class. Those who wish to read in more detail the reasoning behind our figures of merit (and the debate around them) should check out the blog entry (and comments) Is Electricity a Fuel or Just an Energy Carrier? (, and also these FAQs on pages 61-63 of the Competition Guidelines ( What is the basic reasoning behind the two figures of merit? Why measure fuel economy pump-to-wheels rather than wells-to-wheels? Don’t electric vehicles have a huge advantage? Mr. Bullis’ opinion is valid, in the sense that a reasonable alternative choice is to define MPGe by including upstream energy conversions. But our choice is neither dishonest, nor the result of ignoring the laws of physics. For the record, we (along with Argonne, EPA, DOE, and Dr. David MacKay of the UK DOE) have not decided to cancel the Second Law of Thermodynamics.