Combination of RNG/Renewable Natural Gas and NZ Engine
To Meet Goals Faster and Cheaper than Batteries or Hydrogen
The super low-NOX engine from Cummins Westport, powered by RNG/renewable natural gas, will allow California to meet its goal of zero-emission transmit buses more quickly and for less money that it will with battery electric or hydrogen fuel cell buses, says a new analysis.
Fleet costs will rise by just 1% with LNOx+RNG, as compared to 8% to 14% for all-electric buses or 9% to 13%, according to a presentation last week by by Dana Lowell of M.J. Bradley & Associates and Julia Lester of Ramboll/Environ for LA Metro.
LA Metro switched entirely to compressed natural gas operation in 2011 – the currently operates 2,194 CNG buses, according to Bradley-Ramboll – so would face no infrastructure/depot-upgrade costs to make the switch to LNOx+RNG.
‘An Order of Magnitude More Cost-Effective’
Battery bus charging infrastructure, by contrast would cost some $36,000 per vehicle, while deport modification for fuel cell buses (hydrogen sensors and ventilation) would cost about $28,000 per vehicle, the analysis found.
In summary, states the report, over the next 40 years the use of RNG and transition to Low NOx CNG engines will be
- more effective at reducing GHGs from the LACMTA fleet than transition to either electric or fuel cell buses;
- more effective at reducing in-basin NOx emissions than transition to fuel cell buses, and almost as effective as transition to electric buses; and
- significantly less expensive than transition to either electric or fuel cell buses.
Emission reductions of both GHG and NOx from LNOx engines and RNG “are an order of magnitude more cost effective than reductions from transition to electric or fuel cell buses,” the report concludes.
LNOx+RNG, says LA Metro of vehicle technology director John Drayton, “is a very viable immediate strategy for a lot of operators. We have the ability to implement a low-NOx CNG program here virtually immediately.”
‘We Will Probably Do Both’
The caveat? Fuel cell and batteries are becoming more competitive as technologies evolve and costs drop. “We expect this Ramboll/Environ report to be a living document that will help guide Metro’s technology decision-making,” Drayton told F&F.
With regard to LowNOx with RNG or zero-emission? “We will probably do both.”
The “Near Zero” Cummins Westport engine technology introduced last year and made available this past April as an option on the 8.9-liter, dedicated-natural gas spark-ignition ISL G, is certified at just 0.02 grams per brake-horsepower – 90% below 2010 U.S. EPA requirements (F&F, October 6).
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Source: LA Metro with Fleets & Fuels follow-up