compressed_natural_gas_bus

Transit buses fueled by natural gas more viable than diesel or electric

Researchers at Purdue University found that a local bus system running on natural gas is more economically feasible and less harmful to the environment than the currently employed diesel model. The team lead by  Purdue University energy economist Wally Tyner also concluded that natural gas is a better fit than electric-hybrid.

compressed_natural_gas_busThe analysis was  was specific to the Greater Lafayette Public Transportation Corp., also known as CityBus, which operates 72 buses and cares for 30,000 riders daily. The team prompts, however, that their findings can be extended across all bus systems across the country.

The company already runs a couple of diesel-electric hybrid buses which have a higher fuel economy than a standard diesel bus but considerably higher capital expense in the form of higher bus costs. While operation costs can make diesel-hybrid buses feasible in the long run, high capital costs makes the initial investment difficult to make.

“Because of the lower fuel price and pollution reduction, the CNG bus is considered to have good potential as an alternative vehicle used in the public fleet in the United States,” Tyner writes

Purdue researchers found that over the course of 15 years, even with the $2 million expense of building a natural-gas fueling station, the natural-gas system would cost $48 million over the span of the project, compared with $54 million for the diesel-electric and $48.5 million for the diesel-only, according to the report. The analysis takes into account fluctuations in diesel and natural gas prices, operation costs and maintenance.

“Moreover, from the environmental perspective, the implementation of compressed natural gas (CNG) buses in the fleet would also produce less emission and provide benefit to the environment of the local society,” the report says.

The  natural-gas option has a 65 percent to 100 percent chance of being lower cost than the diesel option, considering fuel price forecasts. Natural gas has become ever cheaper in recent years mainly due to massive shale gas exploitation. Shale gas production is expected to increase until 2035.

Full report can be viewed here.

One thought on “Transit buses fueled by natural gas more viable than diesel or electric

  1. shusa2013

    This “study” is seriously flawed and reads like it was prepared by the natural gas lobby. I wondered who paid for this “study”. Similar reports from other universities have come under serious question due to financial conflicts of interest.

    One of the most ridiculous claims is this: “Moreover, from the environmental perspective, the implementation of compressed natural gas (CNG) buses in the fleet would also produce less emission and provide benefit to the environment of the local society.”

    Really? Clean diesel is a very good environmental and fuel efficiency choice for transit systems. Because of this, transit systems in New York City, Baltimore, Chicago, Pittsburgh and around the country are adding clean diesel and diesel-hybrid to their fleets.

    The Clean Air Task Force conducted an analysis comparing 2012 CNG buses to 2012 clean diesel buses, which is significant because the natural gas industry often compares 2012/13 CNG buses to older diesel technology to inflate the CNG environmental “advantage” over diesels.

    According to the analysis entitled Clean Diesel versus CNG Buses: Cost, Air
    Quality, Climate Impacts: “Both new diesel and new CNG buses have
    significantly lower emissions of NOx, PM, and HC than the older diesel buses
    that they replace. According to EPA’s MOVES emissions model a 2012 model year diesel bus emits 94% less NOx per mile, 98% less PM, and 89% less HC than a model year 2000 (12-year old) diesel bus. A model year 2012 CNG bus emits 80% less NOx, 99% less PM, and 100% less HC than a model year 2000 diesel bus.”

    In addition, the analysis stated: “Replacing 10 older diesel buses with new
    diesel buses will reduce annual NOx, PM, and HC emissions by 4,953 kg, 275 kg, and 421 kg respectively. Replacing 10 older diesel buses with new CNG buses will reduce annual NOx, PM, and HC emissions 4,197 kg, 279 kg, and 471 kg respectively. On a per-bus basis new CNG buses provide slightly greater PM and HC reductions, but lower NOx reductions,than new diesel buses.”

    With such serious flaws in its environmental analysis, I have no doubt the Purdue “study” is just as inaccurate in its economic “analysis”.

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