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DE60LF
Joined: 03 Oct 2007 Posts: 142 Location: Albuquerque, NM
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Posted: Fri Mar 21, 2008 1:03 pm Post subject: CNG vs diesel-electric hybrid technolgy on a global scale |
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In the United States and Canada, diesel-electric hybrid buses are becoming the alternative technology of choice, and will eventually overtake CNG. However, what I find strange is that outside the U.S. and Canada, CNG is still the predominant alternative tecnology of choice. Why is this?
According to New Flyer, diesel-electric hybrids have emission levels well below the level of CNG buses, and have nearly double the fuel economy. So, why in most of the world, particularly in Europe, are CNG buses still dominant? I know there are a few diesel-electric hybrid buses operating in Japan, however, they are rather rare (although not non-existent, as Mercedes introduced a diesel-electric hybrid Citaro) in Europe. Doesn't Europe have stricter emissions laws than the U.S.? I don't see a real reason why CNG is preferred over diesel-electric hybrids. |
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The Port of Authority
Joined: 16 Apr 2007 Posts: 118 Location: Hong Kong
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Posted: Fri Mar 21, 2008 5:44 pm Post subject: |
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I wouldn't go so far to include the entire United States as having embraced diesel-electric hybrids -- California, for example, mostly goes with CNG, LNG, and gasoline-electric hybrid buses. |
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DE60LF
Joined: 03 Oct 2007 Posts: 142 Location: Albuquerque, NM
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Posted: Fri Mar 21, 2008 8:15 pm Post subject: |
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The Port of Authority wrote: | I wouldn't go so far to include the entire United States as having embraced diesel-electric hybrids -- California, for example, mostly goes with CNG, LNG, and gasoline-electric hybrid buses. |
Well, that is only because of emissions laws in southern California, where TAs are prohibited from using any form of bus using diesel fuel, regardless of whether it is ULSD or a diesel-electric hybrid.
ABQ RIDE's 300 series (Neoplan AN440A, delivered 1996) and 400 series (Thomas/Dennis SLF200, delivered 2001) buses are all CNG powered, however, all new ABQ RIDE buses since 2004 (6400 and 6600 series New Flyer DE60LF, and 700 series New Flyer DE40LFR) have been diesel-electric hybrids. I don't expect ABQ RIDE will order any more CNG buses anytime soon.
Also, NYCT operates both the Orion VII CNG and the Orion VII HEV, and has determined that the HEV is more economical to operate.
As for gasoline electric hybrids, that could be an option, however, ULSD produces emissions well below the level of gasoline. Gasoline actually produces more carbon monoxide, which is converted into the atmosphere into CO2, contributing more to global warming. |
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CAT218
Age: 53 Joined: 02 Jan 2008 Posts: 17 Location: Las Vegas, NV
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Posted: Fri Mar 21, 2008 10:48 pm Post subject: |
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From what I've seen, that is not true about double the mpg. RTC's New Flyer CNG vehicles are averaging about 3 mpg while the DE41LFR's are averaging a little under 4. Believe me I pretty much have all of our fuel consumption memorized as we have been doing a lot of blocking based on fuel consumption and trying to place the hybrids on the longer blocks as much as possible even if it's only about a mile per gallon more. |
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DE60LF
Joined: 03 Oct 2007 Posts: 142 Location: Albuquerque, NM
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Posted: Sat Mar 22, 2008 4:57 pm Post subject: |
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CAT218 wrote: | From what I've seen, that is not true about double the mpg. RTC's New Flyer CNG vehicles are averaging about 3 mpg while the DE41LFR's are averaging a little under 4. Believe me I pretty much have all of our fuel consumption memorized as we have been doing a lot of blocking based on fuel consumption and trying to place the hybrids on the longer blocks as much as possible even if it's only about a mile per gallon more. |
Well, ABQ RIDE has stated that the new DE40LFRs get about 4.5 mpg, while the old TMC RTS diesel buses get about 3.2 mpg. By design, CNG buses have inferior fuel economy compared to diesel electric hybrids or even regular diesel buses.
From what I have heard, ABQ RIDE's Neoplans have to be refueled daily, while the new DE40LFRs can go for several days without being refueled. As for the Thomases, since they have a smaller engine than the Neoplans (Cummins B-Gas Plus vs. the Cummins L10G engines on the Neoplans), they probably get better fuel economy. The latest New Flyer C40LFs use a Cummins ISL-G engine, which is slightly smaller than the L10G, but larger than the B-Gas Plus.
Also, ABQ RIDE's newest garage, the Daytona Transit Facility, isn't even equipped with CNG, so the CNG buses (Neoplans and Thomases) continue to operate out of the older Yale Transit Facility.
No offense to CNG supporters, however, the diesel-electric hybrid path is the way to go for the future. As for hydrogen fuel cell technology, as of now the technology is very expensive, and it will take several years for costs to go down. |
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