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Edmunds Data Proves Diesel "Break-Even" Is Shorter Than Hybrids

With a new crop of diesel vehicles poised to invade the U.S., Edmunds.com has discovered that diesels present an even better choice for fuel-economy-minded consumers than hybrids.

Diesels cost more than their gas-powered equivalent vehicles, but this higher purchase price is quickly offset by fuel-economy savings and tax rebates in some models. With hybrid vehicles, this so-called break-even period is longer — in some cases many years longer.

With high fuel prices, consumers are steering their car purchases toward vehicles that get better fuel economy. For many shoppers, this means their first thought is to buy a hybrid vehicle. But in light of this new data, they should also consider a diesel vehicle, said Jessica Caldwell, Edmunds.com analyst.

"Diesel engines produce a greater fuel-economy boost over their gasoline counterparts than do most hybrid powertrains," said Caldwell. "This makes it a great choice for anyone tired of rising oil prices."

Case in point: The Mercedes E320 BlueTEC costs more to buy than its gas-powered counterpart, but the improved fuel economy it delivers pays for this higher cost differential in only 4.1 years. Compare this to the scenario where a car shopper chooses the Lexus GS450h Hybrid over the Lexus GS460 gas-powered car. In that case the better fuel economy of the Lexus GS450h takes 18.6 years to pay for the cost difference (see chart below).

In another, more dramatic example, the Mercedes-Benz GL-Class with a diesel engine gets 35.7 percent better fuel economy than its gas counterpart. The GL320 BlueTEC has an immediate break-even point, so the moment you purchase it, you are saving $343 dollars a year in fuel costs. This is primarily due to its tax rebate, and the close price differential to the non-diesel version. The R320 BlueTEC also has an immediate break-even point.

Turning to hybrids, the Cadillac Escalade Hybrid saves $748 a year in gas but takes 6.3 years to justify its extra cost.

So if diesels are so thrifty, why don't more people choose them?

"In the past, diesels have gotten a bad rap in this country," said Director of Vehicle Testing Dan Edmunds. "The diesels that were sold here were slow, noisy and smelly. But all that's about to change."

Breakthroughs in diesel technology by Mercedes and Volkswagen will mean that they can again be sold in states with tough air quality restrictions. The new diesels, with impressive fuel-economy benefits, is likey to steal some of the fuel-economy market share from hybrids.

Additionally, diesels are a good option for consumers who want to cut their use of foreign oil and show their support for energy independence. Diesels can run on biodiesel, produced in the U.S. from crops such as soybeans, with little or no modification. Biodiesel is often more expensive than "petro-diesel" but there is little drop-off in fuel economy between the petroleum-based fuel and the biofuel. This is not the case with E85 (85 percent ethanol and 15 percent gasoline), which costs less to buy but because of a steep decline in fuel economy is ultimately more expensive to operate.

"Another point in diesel's favor is that it offers a better 'well-to-wheels picture than a gasoline-powered car,'" said Edmunds, referring to the entire environmental impact of drilling, refining and shipping the fuel to the filling station. "Diesel requires less energy to refine and then provides more fuel economy when it's burned — that's a double win for environmentally minded consumers."

There are, however, drawbacks to diesel passenger vehicles, Rosten cautioned. Few models are currently available and there are tight restrictions on diesels sold in eight states — California, Connecticut, Pennsylvania, Maine, Massachusetts, New York, Rhode Island and Vermont. The 2009 Mercedes-Benz and Volkswagen diesels are the only models legal in all 50 states.

Still, many experts believe that the benefits far outweigh the drawbacks. And for anyone looking for a new option to hybrids, diesels are definitely worth consideration. Eventually diesels will be combined with hybrid powertrains, making it the best of both worlds.