Friday, January 07, 2005

Hybrid Buses' Fuel Economy Promises Don't Materialize

Expensive new hybrid diesel-electric buses that were portrayed by King County Metro as "green" heroes that would use up to 40 percent less fuel than existing buses have fallen far short of that promise.

In fact, at times, the New Flyer hybrid articulated buses have gotten worse mileage than the often-maligned 1989 dual-mode Breda buses they are replacing. Yet the hybrid buses cost $200,000 more each than a conventional articulated diesel bus.

In May of this year, when Metro held a public event to herald the arrival of the first of the new hybrid buses, County Executive Ron Sims said they would save 750,000 gallons of fuel a year over the Bredas.
What makes this better is that right next to this article in the newspaper was an ad from GM entitled "All aboard the Magic Bus" that claims GM hybrid-powered buses increase fuel efficiency up to 60%. And it also mentions the 750,000 gallons of savings. Nice. Check out this old press release stating the savings.

So where did the mythical 750,000 number come from and why has it not come to pass? Not quite clear.
The hybrids were not getting much better than 3.6 miles per gallon.

Boon said that today, the hybrids sometimes get better mileage than the conventional diesels and the Bredas. But it's difficult to compare different models, he said.

"It's comparing apples and oranges and pears."
First off "and pears"? There are no pears, there are just apples and oranges. No one compares anything with pears. That is just plain silly. Get with the program buddy.

What is Boonie's explanation for the discrepancy between the predicted 750,000 gallons savings and reality? He takes the tried and true strategy of using every explanation and hope one sticks and hope no one notices that they contradict each other.

Explanation 1: We didn't expect any fuel savings. We bought them for the improve maintenance and lowered emissions.
"We didn't buy this (hybrid) bus because of fuel economy," Boon said. It has other desirable attributes, such as being cleaner, quieter, and saving on oil consumption and operating costs, but the tunnel forced the choice of the hybrids. The hybrid fleet as a whole is saving $3 million a year in maintenance costs over the Bredas. And they're quieter than regular diesel buses and faster than the Bredas on hills and the highway. They also have very low emissions.

Despite the public claim of fuel savings, Boon said that when Metro prepared its budget for 2004, it projected no fuel savings.
Well then who the heck approved the press release about the 750,000 gallons in savings?

Excuse 2: The vendor switched the engine on us and we lost the fuel savings.
That's not what was expected of the bus. In an October 2002 e-mail, Boon said, "The vendor indicates that hybrid buses can achieve up to 60 percent in fuel savings, but I am only projecting 20 percent to 30 percent given our hills and traffic congestion."

A year later, as Metro ordered the buses, the agency said they could reduce fuel consumption by 20 percent to 40 percent.

The early tests were very encouraging. In December, Boon reported to his bosses that the buses were at 15,000 miles and had experienced hardly any mechanical problems. The hybrid was achieving about 32 percent better fuel economy than the Breda -- 4.46 miles per gallon compared with the Breda's 3.37 miles per gallon, he reported.

In January 2003, Todd Gibbs, manager of the hybrids project, said on a posting on Metro's Web site that the hybrid bus was achieving 40 percent better fuel economy than the Breda, even though it was overloaded with the water barrels.

The federal government had imposed stricter exhaust emissions standards, and the Cummins engine was not federally certified. Metro sent the bus to the Winnipeg, Manitoba, manufacturer to have a certified Caterpillar engine installed in its place.

The fuel economy results were never the same after the switch to the Caterpillar engine.
Was the press release given before the change in engines?

Explanation 3: We actually are getting the savings and the gas mileage on the old vehicles is lower then stated.
When he checked recently, Boon was told that Bredas are running at about 3.8 miles per gallon, while the conventional diesel older New Flyer articulated buses are running about four miles per gallon. The hybrids were getting 3.75 miles per gallon in September

"I've got hybrids that are getting four," he said recently. And Boon said he was surprised when he was told that Bredas were getting 3.8, because they've more typically been below 3.5.

Ok, then how many gallons are you really saving? Can't you give us the total number of gallons the old buses used vs. the new buses running the same routes?

In case you are like me and got confused about the gas mileages, it is because they stated multiple ones and never really cleared up which was the best estimate:
Old Buses (Bredas): 3.37, 3.5, 3.8
New Hybrids :3.6, 3.75, 4, 4.46

Well at least they are quiet when they come to a stop.

via Seattle PI

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