In advertisements, fuel economy numbers are the ones that count. In auto showrooms, the window stickers explain these numbers. These stickers are absolutely critical to plug-in cars' prospects in the marketplace, and have been a long time coming. We've had five years of excitement about the100+MPG cars we could someday drive --now they're about to arrive! So the US Environmental Protection Agency and the Department of Transportation want to get this right. To help you, we provide links to the proposed stickers and to some of the first media stories, followed by our broad explanation and our initial specific technical analysis. We hope those who want to help contribute to the "successful commercialization of plug-in vehicles ASAP" will take Washington up on its invitation to comment in the next 60 days.

OUR OVERALL REACTION: The EPA and the DOT's National Highway Traffic Safety Administration have done an outstanding job. We're glad they've found a way to show MPG-equivalents. And they've created some effective graphics and ratings to explain the cost savings and environmental benefits of miles driven in plug-in vehicles. However, they've made it hard for the public to see what's important in the proposals and to contribute their views. (See specifics below.)

LET'S HEAR FROM YOU: You can add your comments about our report at http://www.plugincars.com , where a version of this posting will appear as a guest column on Tuesday, August 31. And you can transmit your views to the EPA for these regulations, to apply to all cars starting with model year 2012, via the box at the bottom of the page at http://www.epa.gov/­fueleconomy/­label.htm or by email to newlabels@epa.gov.

MEDIA STORIES: If like many people you get the picture best from news stories, here are some of the first:

• NY TIMES: http://wheels.blogs.nytimes.com/­2010/­08/­30/­e-p-a-develops-grading-system-for-new-car-stickers/ reports on the motivations for the new analyses and reports initial pushback from the U.S. auto industry, especially on the idea of issues A-D ratings for different vehicles.
• GM-VOLT.COM: http://gm-volt.com/­2010/­08/­30/­epa-proposes-new-phev-and-ev-fuel-economy-labels-wants-your-comments/ includes a description, links, and many comments.
• HYBRIDCARS.COM (sister site to plugincars.com) http://www.hybridcars.com/­fuel-economy/­government-proposes-report-cards-fuel-economy-window-stickers-28508.html explains the proposals and provides multiple label images.
• GREEN CAR ADVISOR http://blogs.edmunds.com/­greencaradvisor/­2010/­08/­feds-propose-new-fuel-economy-labels-for-cars-and-trucks-seek-public-input.html provides annotated explanations of the stickers and discusses how different vehicles would be rated in the sure-to-be-controversial rankings.
• GREEN CAR REPORTS http://www.greencarreports.com/blog/1048815_epa-proposes-two-designs-for-updated-fuel-economy-labels-wants-your-input describes the new labels and how ratings would be applied.
• AUTOBLOG GREEN http://green.autoblog.com/­2010/­08/­30/­epa-finally-issues-proposed-fuel-economy-labels-for-plug-in-vehi/ compares the two stickers.
• WIRED.COM http://www.wired.com/­autopia/­2010/­08/­feds-propose-letter-grades-for-vehicle-efficiency/ focuses largely on the letter rankings and their implications.

THE BASIC DOCUMENTS: Your starting point is the documents about the ruling at http://www.epa.gov/­fueleconomy/­label.htm . Here's where understanding the proposals immediately gets complicated. The site links to two main documents:

• A 7-page brochure designed for the public: http://www.epa.gov/­fueleconomy/­label/­420f10049.pdf , which includes two label options for the five standard vehicle types: gasoline & diesel (this includes conventional hybrids), electric, plug-in hybrid, flexible-fuel, and compressed natural gas. A small footnote on the cover page saying that the government is "also seeking comment on a third label design" sounds like an afterthought.
• Hard to find on the same page is "See All Labels," a second 19-page plain document with only images and no explanations, titled "Proposed Fuel Economy Labels in EPA and DOT Notice of Proposed Rulemaking" http://www.epa.gov/­fueleconomy/­label/­label-designs.pdf . Yes, this document includes that third (relatively inconsequential, most similar to today's) label design, but more importantly, it ALSO includes both "blended" and "extended range electric vehicle" (EREV) variants on the PHEV vehicle type.

This second document shows that people who view only the main summary document will have an incomplete picture of what's being proposed. While the explanations emphasize that the numbers used are illustrative, not referring to any particular car, the ones they picked are illuminate what's missing. Page 4 of the short brochure shows proposed Option 1 & 2 labels for a PHEV (also described as a "dual fuel vehicle: gasoline-electricity") with a 50-mile blended gas/electric operating resulting in a 65MPG equivalent for those first 50 miles, then 38 MPG with a depleted battery. That same Option 2 graphic is on page 12 of the second document, at a page labeled "PHEV (predominantly blended type) (Figure III-12)". But one page before, on page 11, is a page labeled "PHEV, extended range electric (series) type (Figure III-11)" -- a vehicle type that's not found in the shorter document. That vehicle has a 98MPG equivalent for its first 30-miles, then 38MPG. Page 7 shows an Option 1 graphic for a PHEV with an 11-mile EV range.

This all means that the short presentation omits from the main document -- and doesn't present completely in the long one -- the EREVs/series hybrids that will come to market first: the Chevy Volt, followed soon by the Fisker Karma. And it doesn't even present well the Toyota Prius blended PHEV that will follow. Presumably the EPA/DOT were attempting to simplify the issue -- but too much was lost.

CALCARS' DETAILED COMMENTS: These are largely the work of our Technology Lead, Ron Gremban. In the interest of encouraging broad discussion during a week when it's hard to reach people, we are providing preliminary starting points quickly and hope they will provoke additional responses.

We are focusing on the 19-page document at http://www.epa.gov/­fueleconomy/­label/­label-designs.pdf (which, as described above, includes separate EREV and blended-PHEV labels for both Label Option 1 and Label Option 2, and adds a Label Option 3 as well), rather than to only the more limited options shown in the 7-page brochure .

The EPA and DOT have done an outstanding job. These labels are great, and reflect serious thought and environmental consideration! And inclduing codes scannable by smartphones, they will empower consumers to find out much more.

The top half (down to the section on 5-year extra fuel cost or savings compared to an average vehicle) of Label Option 1, for all vehicles, is superb, and provides maximum incentive for buyers to buy green. We hope these ratings and fuel savings are included in the final label design. They produce the ratings that carmakers with many low-ranked vehicles won't want in new car windows in showrooms! Those savings over years (and the demonstrated long-term higher cost of low-ranking vehicles) will provide the best reasons for customers to buy vehicles with high fuel economy and those using clean and cheap electricity.

Although the numbers are placeholders, we suggest a higher price than $2.80 per gallon for gasoline -- both U.S. and international oil agencies now expect the price of oil (unlike electricity and natural gas) to increase significantly over the next five years. And we see a strong argument for using a 36.4 kWh per gallon high heat value of gasoline rather than the 33.7 kWh low value. (The extra energy is what's required to vaporize the water vapor in the exhaust, which might conceivably be condensed and recovered in an extra-efficient gasoline vehicle.) But these are minor quibbles with an otherwise-outstanding set of labels.

We see Label Option 2, for all vehicles, as superior to both Label Option 3 and the bottom of Label Option 1 in laying out the details of vehicle performance. We strongly recommend combining the top of Label Option 1 with all of Label Option 2.

The following points are about Label 2's exceptional features and a few recommendations for minor improvements.

Starting with the gas/diesel vehicle (Figure III-9), the gas pump icon, next to the MPG figure and the associated annual fuel cost, all offer obvious visual contrast to the plugs used for EVs and PHEVs. The plots of overall MPG, CO2, and other pollutants on bar graphs read well, too; and are similar to what consumers have seen for years on appliances. Displaying only tailpipe emissions may be the only way to reflect that 'well-to-tank' pollutants vary dramatically between locations and over time, with sources of electricity becoming increasingly clean, while more gasoline is starting to come from such high-CO2 sources as tar sands.

A minor point: throughout, for emissions, we would urge the use grams per kilometer instead of grams per mile. Most consumers will not relate to the absolute number anyway, and what is shown already takes a half step with grams instead of fractional ounces. Why not fully embrace the scientific metric units used by carmakers and governments everywhere else in the world?

We're delighted to see the gallons per 100 miles figure included. This is a much more important figure than the dumbed-down miles per gallon measure we've grown up with. Seeing it alongside MPG on vehicles will improve consumers' understanding of how fuel economy relates to vehicle size. In fact, taking it one step further, gallons used driving the typical 15,000 miles per year would be even better. Then the huge-seeming 50 MPG difference between 50 and 100 MPG would show up as saving just 150 gallons in a year, while the much smaller-seeming change when a 10MPG vehicle gets 20MG would save 750 gallons -- five times as much.

The EREV (Figure III-11) label ably explains a complex concept, The line below the two MPG boxes, showing a car driving first "All Electric," then "Extended Range (gas)" is inspired. It clearly shows how the vehicle is powered, with arrows from the electric and extended range miles to the two MPG boxes with electric and gasoline icons, and the 240-Volt charge time shown next to a battery. The "nameplate capacity" of the battery (the basis for federal incentives), is also of value and could be included inside a larger battery icon. Crucially, the boxes show both the "cost per year if always run in All Electric," which an EREV driver rarely exceeding the daily charge range would approach. And it includes the worst-case "cost per year if always run in Gas Only" mode. This latter number would apply only for an unusual driver who decided not to bother spending 15 seconds plugging and unplugging when an outlet was available.

The label for blended-mode PHEVs (Figure III-12) is likewise clear. We would suggest using a color between the electric green and the gasoline yellow to make the blending more obvious compared to the EREV and pure EVs. And perhaps find a way to include kWh per 100 miles along with gallons per 100 miles for the blended mode, so consumers have a way of knowing how much electricity is being used.

This discussion will continue. We hope many interested parties will weigh in publicly and to the federal government. Comment about this posting at http://www.plugincars.com and view the documents and send your views to the EPA at http://www.epa.gov/­fueleconomy/­label.htm .