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Wednesday, June 15, 2011

New EPA Fuel-Economy Stickers for Gas Vehicles, Plug-in Hybrids, and EVs Explained

It was just a few months ago that we dissected the convoluted fuel-economy sticker on the Chevy Volt, but if you didn’t get a chance to figure that out, don’t bother. The EPA has released a set of all-new stickers for cars and light trucks that will be mandatory for the 2013 model year. Use of the new sticker is optional for 2012, so you could see it in showrooms as early as this fall. Why this, why now? According to the EPA’s online fact sheet, the new labels “highlight the increased efficiency standards achieved under the Obama Administration that will save families money at the pump starting this year.” How’s that for grandstanding? Politics aside, the new labels are meant to provide more-detailed information about energy consumption and ownership costs. Plus, the labels give a consistent, easy-to-read look for plug-in hybrids and EVs.

The Basics

All labels have a projected annual fuel cost (and yes, it says “fuel” on the EV label) and five-year estimate for how much you save or spend compared to the projected CAFE average of all vehicles in that model year. The other universal elements to the labels are the “Fuel Economy & Greenhouse Gas Rating” and “Smog Rating” sliders. The greenhouse-gas rating is strictly a measure of tailpipe CO2 emissions (which is directly proportional to fuel consumption) and doesn’t count any upstream emissions for electricity production. The smog rating is based on emissions of non-methane organic gases, oxides of nitrogen, particulate matter, carbon monoxide, and formaldehyde. The smog rating also is tailpipe-only; EVs and hydrogen fuel-cell vehicles get a pass on both of these rankings.

Your Mileage May Vary

Gasoline, diesel, and E85 ratings are simple: a big combined fuel-economy figure is accompanied by smaller city and highway figures. E85 vehicles will actually display gasoline mpg; optional inclusion of E85 fuel economy is a future possibility. The reason for this, according to the EPA’s final ruling, is because “Data show that, on average, FFVs operate on gasoline nearly 99 percent of the time, and on E85 fuel about 1 percent of the time.” Sorry, Iowa. Compressed natural gas and hydrogen vehicles look similar, only with mpg-equivalent figures.

Another number on the label is consumption rate in terms of gallons per 100 miles. Despite our American attachment to mpg, consumption rate is a great way to look at fuel economy. For example, consider a 25-mpg car and a 40-mpg car. When viewed in terms of consumption rate–4 gallons per 100 miles compared to 2.5 gallons per 100 miles–the difference is perhaps even more  pointed. Consumption rate also makes it easy to figure out relative fuel costs.

Conventional hybrid vehicles will get a standard gasoline sticker. Plug-in hybrids are broken into two categories, blended or series. Blended PHEVs include the plug-in Toyota Prius, where electric-only operation is possible at low speeds but the gasoline engine is still used when needed. Series PHEVs, like the Chevrolet Volt, can operate in full electric mode until the battery is depleted. Both types show 240-volt charge time, an mpg-equivalent combined city/highway rating, and range for either the blended or electric-only mode. Blended PHEVs also show the corresponding gasoline and electricity consumption (per 100 miles), while series PHEVs simply show the electricity consumption. This is essentially the same information presented on the old Volt EPA sticker, but the presentation is easier to read.

Finally, the label for pure-electric vehicles is much like the gasoline label, with the addition of 240-volt charging time and consumption rate expressed in kilowatt-hours per 100 miles. For both EVs and PHEVs, the electric consumption rate is wall-to-wheels, so it accounts for the electricity used to charge the battery and not just the electrical energy used to move the vehicle.

View the original article here

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