Various studies have compared the emissions of biodiesel, SVO/WVO, and petrodiesel. The EPA reports that, compared to petrodiesel, biodiesel reduces emissions of hydrocarbons, carbon monoxide, and particulate matter. Test results published in a May 2006 Consumer Reports article reported that biodiesel and SVO also produced fewer particulate emissions, but greater hydrocarbon emissions than petrodiesel. In terms of NOx, biodiesel had the highest emissions, and SVO had the lowest emissions. Most studies agree that burning biofuels does produce fewer health hazards compared to petrodiesel.
Thus far, hybrids sold in the United States have been gasoline-electric hybrids. Since the primary power plant is an internal combustion engine, these hybrids are still heavily dependent upon petroleum. Diesels are dependent upon petroleum as well, but to a lesser extent if the fuel is biodiesel or SVO.
One of the inherent drawbacks of petroleum as a transportation fuel is that it is not renewable. While the amount of untapped world oil reserves may be debated, one fact is undeniable: There’s only so much oil underground. Biofuels like biodiesel and SVO are renewable. More crops can be grown to replace the “fuel” that has been harvested from oil-bearing crops like canola, soybeans, and peanuts. To sweeten the deal, these sources could be classified as “carbon neutral.” The carbon dioxide released into the atmosphere when their oil is burned as fuel equals the amount captured while the plant was growing. Petroleum fuels cannot make this claim.
But what about ethanol, a renewable biofuel for gasoline engines? Ethanol is renewable, and a cleaner-burning fuel than gasoline, but it has a lower energy content than gasoline, so you’ll have to burn more fuel to travel the same distance. No hybrid on the U.S. market is designed to use ethanol or even the much publicized, but still difficult to find, ethanol blend. Although Ford is testing an E85 (85 percent ethanol; 15 percent gasoline blend) Escape Hybrid, at this point, ethanol is moot.
More than 50 percent of the petroleum used in the United States is imported. And, according to the American Council for an Energy Efficient Economy, the vehicles we drive gobble up a little more than half of that imported oil. Growing demand from countries like China means stiffer competition for oil and higher costs in the future, so it makes good business sense to develop alternative domestic sources of transportation fuel and the vehicles to use them. A diesel vehicle or a diesel-electric hybrid could use a domestically produced fuel like SVO. (Although no diesel-electric cars have hit the market yet, both General Motors Corp. and Mercedes-Benz have concept cars on the road.) Since the U.S. market currently has no gasoline-electric hybrids capable of running on E85, the final event goes to diesels.
When the dust and the exhaust smoke settles, is there a clear winner? As you’ve probably figured out, there’s no pat answer to finding sustainable, economical, and environmentally friendlier transportation solutions. Ultimately, you’ll need to weigh your needs against the available options to find the wheels that are right for you.
If you need a greener get-around-town car, and want something new, a hybrid may be your best bet. They are price-competitive with most new diesels, although their limited production numbers may mean putting your name on a waiting list. Here’s the hybrid hype and dirt on diesels, though—newer standard gasoline models introduced this year, like Toyota’s Corolla and Yaris, and Honda’s Fit, are edging up on them in terms of fuel economy—all while doing less damage to your bank account, with prices of almost half that of hybrids and diesels. The Corolla and Yaris get a respectable 40 mpg on the highway, and the Honda Fit gets 38 mpg.
If you need four-wheel drive, the new hybrid SUVs beat the wheels off their gasoline-only counterparts, and even trump the mileage of comparable diesel models (the Jeep Grand Cherokee diesel and VW Touareg). Hybrid options for light-duty trucks are limited to Chevrolet’s Silverado, which gains you an extra 1 to 2 mpg—a 5 to 10 percent improvement, and still helpful—compared to its nonhybrid version. As for new light-duty diesel trucks—forget it. (In the pre-owned market, you may be lucky to stumble on some older-model diesel Toyotas and Volkwagens). No heavy-duty hybrid trucks are now available, and diesels still remain the workhorses. Diesel trucks only get moderately better mileage than their gasoline-guzzling cousins (and some get the same, so do your research first). But if you install an SVO-kit, they can run on free fuel—if you can find it and don’t mind getting your hands dirty.
Ray Holan • www.burningriverfuels.com
Adapted in part from Sliding Home, 7th ed. by Ray Holan, 2006, spiral bound, 308 pages, ISBN 0-9777247-052650, $25, available from www.goldenfuelsystems.com, www.greatlakesbrewing.com, www.koalamotorsport.com, or www.plantdrive.com
U.S. EPA/EERE Fuel Economy guide • www.fueleconomy.org
Kelly Blue Book • www.kbb.com • Vehicle prices