CNG Trash Trucks for NY

One of the general conclusions that most people come to after serious study of peak oil and how we can adapt to it is that there is no one-shot solution. Rather a wide variety of niche solutions will fill many of the puzzle pieces and together can help maintain a certain level of societal complexity.

One possible niche that seems almost too perfect would be to fuel garbage collection trucks with CNG, preferably converted from methane gas from anaerobic digestion that would have otherwise have been released into the atmosphere . A nationwide fleet of more than 126,000 Garbage trucks operate daily in almost exclusively residential areas including the most dense urban areas of the country. They are a major contributor of ground level pollution and unhealthy air. At the same time, 450-650 billion cubic feet per year of methane waste leeches out of landfills each year which is a significant contributor to greenhouse gases.

In an Op-Ed piece written by Johanna Underwood, the Founder and former president of INFORM (a non-profit research organization) in today's NY Times it was revealed that Smithtown, NY recently decided to switch over it garbage fleet to CNG and this may be the first of many in the local area to recognize the benefits.

SOME may think Smithtown an unlikely pioneer in a major technology revolution. But last month, leaders of this community of 116,000 made a historic decision: by January, all refuse trucks serving the town must be powered by natural gas instead of diesel fuel. Smithtown is the first community on the East Coast to do this, and, if we’re lucky, other cities will follow its lead. Why should communities buy new, different and seemingly more expensive refuse trucks? The big heavy diesel trucks, providing an essential service, rumble down residential streets nationwide largely ignored by citizens (unless, of course, they don’t pick up the trash on time). But recent research conducted by Inform, under my leadership, shows that we can’t afford to ignore them anymore.

In May, Stephanie Mandell of the Sustainable transportation program at INFORM wrote about the many benefits of CNG powered municipal vehicles in Gotham Gazette. She also contrasted that to the current situation with Sanitation trucks:

Per mile, refuse trucks consume the most fuel of any vehicle on the road, burning one gallon of diesel fuel every 2.8 miles. Partly because they are among the oldest vehicles on the road (nationally, 41 percent of them have been in use for more than 10 years), garbage trucks are among the most polluting vehicles. As trucks age, their pollution controls deteriorate, allowing higher levels of pollutants to escape into the air. A recent report by INFORM (in pdf format) calculated that the 3,607 diesel-fueled refuse trucks operated by private garbage haulers in the city collectively generate as much as 9,500 tons of soot and pollutants per year. Thousands more tons spew from the Department of Sanitation's 2,500 diesel-powered refuse trucks.

Robert Rapier applauded Rhode Island's choice for choosing to sell Compressed Natural Gas (CNG) because CNG offers a good 50-60% reduction of ground level carbon monoxide emissions and because of the potential to develop renewable domestic supplies of CNG from landfill methane and collect stranded natural gas from around the world and transport it to the US through LNG tankers and ports.

Similar to how biodiesel might provide a niche in use for important functions like food distribution, basic municipal functions (police, fire, mass transit, sanitation), investing in CNG vehicles may play an important role in preserving reliable and possibly renewable fuel supplies to the most important vehicles in our society.

Local sanitation departments could become net fuel producers if they close the loop of waste from their landfills and the fuel their trucks use everyday. They could use the excess fuel for other municipal vehicles or to create electricity or provide gas for cooking/heating to surrounding homes and businesses.

So where does the current New York City Department of Sanitation stand on this? The latest information I could find on the subject which was contained in an October 2004 report for the Solid Waste Management Plan that was recented passed by the City Council seemed to state a preference for Ultra Low Sulphur Diesel (ULSD) as a way to reduce ground level pollution over CNG which they cite as too expensive for vehicle procurement and infrastructure development (p.9):

"DSNY recently procured 26 new CNG collection trucks. Based on their performance with the first-generation CNG trucks purchased under a contract. One of the major disincentives, however, to creating a CNG refuse fleet is the cost related to puchasing the trucks and infrastructure needed for a CNG facility; a CNG refuse collection vehicle can cost considerably more than a conventional diesel truck and the cost of a CNG facility with fueling, proper ventilation and leakage alarms can be high."

I could not find any further information on how these trucks performed on any metrics or specific costs estimated for what type of investment might be required to have a fleet of CNG trucks. It would be interesting to see the difference in emissions, the difference in noise level, the range and operating costs associated with each after the initial investment and what assumptions were made about the price of diesel.

All of this needs to be investigated, but I hope some imagination is considered in building anaerobic digesters to produce onsite methane that can be converted to CNG and placed back into trucks that collect the waste. The potential benefits to public health through the reduction of carbon monoxide on our streets, the prevention greenhouse gases, could make this a great idea now, even before post-peak oil production dramatically affects the reliability and cost of supplies of gasoline and diesel.

Here's a start: a 1997 DOE report on the CNG fleet. Of course, it needs updating viz. current energy costs to be useful. It also contained the statement that "total hydrocarbon emissions from the CNG trucks were consistently greater than those from the diesel trucks. However, hydrocarbon emissions from natural gas vehicles are typically 90% to 95% methane." Given that methane is a serious GHG, I find it a cause for concern.

Something else to consider: LNG. LNG increases the range of a vehicle by a factor of six over an CNG vehicle for the equivalent volume of fuel. I also think it might be safer to be carrying LNG at atmospheric pressure than canisters of highly pressurized CNG.

I just want to point out that unless there is a reliable supply of methane available (say from a landfill) using CNG is probably worse than using oil domestically because our domestica natural gas production is set to go over a cliff (or steep slope) faster than global oil ever could (knock on wood). But if you can get it from a landfill, that's great. Or if you want to make the investment now, with the idea that it'll be slim pickin's (probably) for a few years and then we'll have this beautiful LNG infrastructure built to import from the same countries that caused our illustrious president to talk about addictions.
Yes, I see this as a way to create a complete system that collects methane from it's landfills, then uses some of that methane to collect more trash, then use some of the excess energy for other municipal vehicles, heating homes, generating electricity or cooking fuel.
I'm sensing a disconnect here. NYC can collect methane from its existing (but closed) landfills. Do they generate enough to fuel the trucks? "New" garbage is shipped out of state or burned for energy. How is NYC going to get the gas generated from the out-of-state landfills back into the city to fuel the trash trucks? I suppose the transfer trucks (those large, over-the-road trucks traveling between NYC and the landfills) could be fueled at the landfills, but not the NYC trash trucks. Also, even if you fueled the transfer trucks, you'd run into the CNG range-limitation of 100 miles or so (which could be overcome by LNG, but that's another thread).
Absolutely agree ... If we have a direct link where a large share (if not all) the gas would come out of the dumps/landfills, then it becomes a counterproductive as we've passed peak natural gas in the United States, as I understand it, and the prices are already extremely volatile.  

RE trash trucks, it seems that this is a fleet that is extremely open to hybrid technologies due to the constant braking and stop/go activity. (Which would have the community 'good' of making less noise much of the time ...)  This hybrid can be with an air compression or hydraulic (rather than electrical) system.

Thus, hybrid CNG trash trucks that are getting their "fossil" fuel directly from the trash they carry, reducing the methane gas emissions from the dump into the atmosphere.

That is an attractive prospect ...

This looks like the first generation of CNG trucks ever developed so there was probably some leakage or engine inefficiency at play to cause the increased emissions. I believe that much of these problems have been worked through. But yes, depending on the emission levels and different types of emissions CNG should only be deployed if it is a net reduction in GHG. That's why I'm so interested in knowing how this generation of trucks are doing.
I wrote a letter to a local biomass energy company, Taylor Biomass Energy asking them if they had considered converting waste into CNG and here was their very quick and interesting reply:

Dear Sir,
We have not considered the use of methane from waste for transportation use for a number of reasons.  First, such recovery requires that all waste go to the landfill - contrary to our primary goal of keeping material out of the landfill.  Secondly, the production of methane by a landfill, is via the production of landfill gas, a mixture of methane, carbon dioxide, and other contaminants.  Recovery of methane from the mixture would be quite expensive and energy inefficient.  Finally, gasification of the sorted and separated wastes provides the option to produce a variety of liquid fuels by way of synthesis of the gas.  In this manner, such products as ethanol, mixed alcohols, or other fuel can be produced with higher overall efficiencies and with little residue remaining to be disposed of in the landfills.

I hope this answers your questions.

Taylor Biomass Energy

It appears that the idea of a closed system for Sanitation vehicles specifically using CNG may be a bit optimistic given current technology, but the idea of making some type of transportation fuel may be practical.

So what should Sanitation vehicles be powered by? Well, as we know, the North American natual gas situtation may deteriorate quicker than the global oil markets. And even after the installation of LNG facilities in our area, it is hard to predict whether that market will be more or less reliable than global oil markets.

The most important piece of information missing is the emissions difference between the 26 CNG trucks in operation and Ultra Low Sulphur Diesel fueled trucks.

What about methane from the city's STP's instead of landfill gas. I remember when I lived in Bay Ridge (15 years ago) and saw the flares from the Owls Head STP. I hope the city is capturing that gas for reuse.
I remember reading in Kate Asher's wonderful book "The Works" that they burn that to generate electricity to run the plant and send some out to the grid
...contrary to our primary goal of keeping material out of the landfill....

Yes, don't need CNG based garbage trucks. Need less garbage. A LOT LESS. Garbage is not an item of commerce, meaning the Commerce Clause does not apply. States should simply ban the incineration or landfilling of "trash". Eliminate trash. Easier said than done, but must be done.


It is hard to get economical progress by hitting the problem with the lawbook.

Over here in Sweden there has been a success with taxing landfills, it has mostly led to large scale garbage incineration that turns the waste into heat, chilling and electricity.
It has also somewhat helped the sorting of garbage usefull for  biogas production or reuse within he building industry and so on.

Our greens realy dont like this since the idea were that there would be no garbage and instead we have more then ever but soon very few new landfills. They are arguing for taxation on garbage incineration, I do not think this will work.

My guess is that we will have this garbage stream untill we hit a depression and people no longer can afford to buy as much new things and parts of the wastes turn valuble.

My recommendation is to in the meantime try to get misc products to contain less harmfull substances such as certain flamability inhibitors and become easier to burn and recycle.

Getting people to not make garbage is a loosing battle, try to get them to make better garbage instead.

UPDATE: Here is some information that I received, but did not have a specific link so I'm copy and pasting from email.

New York City, NY, Department of Sanitation (DSNY)

Contact: Spiro Kattan, Engineering Division

Phone: 718-334-9205

E-mail: skattan [at]

Contact: Rocky DiRico, Assistant Commissioner of Support Services

Phone: 718-334-8911

E-mail: rdirico [at]


Current Natural Gas Fleet: 26 CNG

NG Fleet in 2002: 36 CNG

Refueling: N/A

The New York City Department of Sanitation (DSNY) pioneered in testing the first generation of compressed natural gas refuse-collection trucks fifteen years ago. The DSNY fleet is the largest municipal fleet in the country - with more than 2,200 refuse collection and recycling vehicles.

The early CNG trucks clearly had some particular strengths and weaknesses. According to DSNY Manager Tim Harte in the mid-l990s, sanitation workers "really enjoyed running these trucks on natural gas. The vehicles were quieter and cleaner and there was no diesel knock and no fumes. The drivers appreciated the significantly lower engine noise levels of these trucks. They could "easily talk to each other in the cabs."

However, according to Assistant Commissioner Rocky DiRico, "DSNY had problems with these first CNG trucks, and some of the same obstacles still exist today." In January 2006, DiRico commented on

DSNY's goal, on how its trucks are selected and on its experience with natural gas trucks. "Our mission is to maintain a proactive stance of implementing the 'Best Available Technology' to reduce the overall exhaust emissions of the fleet. Our goal is for DSNY to continue to provide essential services, while maintaining a vigilant and environmentally responsible Clean-Air Program."

"We pre-qualify truck chassis manufacturers to be sure they meet our specifications. We only accept bids from those who are pre qualified. Up until now, only 'Mack Trucks' and 'Crane Carrier' have been pre qualified. The last time we put out a bid for natural gas trucks, Mack came in as the low bidder. The department purchased 26 refuse-collection trucks powered by the Mack E7G engine."

"Mack did not have a strong focus on building natural gas trucks, and we have had a lot of problems with these trucks. For example, their longer wheelbase, because the fuel tanks are between the cab and truck body, has resulted in an inadequate turning ratio. Range has been an issue, even though the CNG trucks were specified with the same capacity as their diesel counterparts. You can't let CNG trucks run low on fuel because the pressure in the tanks drops. We also have had problems with cold weather starts.

Our CNG fleet has also experienced greater downtimes at local dealerships due to a lack of technical knowledge, and replacement parts availability. CNG warranty claims have been much greater than those involving our diesel fleet."

"Despite all this," DiRico added, "we are looking at the new generation of natural gas trucks, and in 2006 we have increased our CNG powered street sweepers from 10 to 20. We appreciate the concern over our country's heavy reliance on foreign oil. We will be opening a new CNG refueling facility in Queens soon, and the biggest challenge at this stage may be adequate refueling infrastructure. DSNY has almost 6000 vehicles in all, so refueling capacity is a big question."

Landfill Gas

A demonstration landfill gas recovery project, conducted in Burlington County, New Jersey, in 2004 and 2005, successfully produced excellent quality gas and used it to fuel two refuse trucks. In this project, landfill gas was purified using a proprietary CO2 Wash system, developed by Acrion Technologies, Inc., which produced a contaminant-free stream of methane (75 percent) and carbon dioxide (25 percent). This methane-carbon dioxide stream was further separated into high-purity methane (less than 100 parts per million CO2) using membranes manufactured by Air Liquide. Additional processing liquefied the methane into high purity LNG truck fuel. The trucks were refueled with LNG at a Chart Industries fueling station located at the EcoComplex facility adjacent to the Burlington County landfill. The fuel powered two Mack trucks, with E7G engines, owned by Waste Management. Mack is now focusing on selling this process commercially and is conducting free assessments for landfills to determine the economic feasibility of building landfill gas recovery facilities.

A landfill gas recovery system is also underway at the Puente Hills Landfill in Los Angeles County.

Run by the Sanitation Districts of Los Angeles County, Puente Hills started the world's first full-scale facility to produce CNG from landfill gas in 1993. Between 1994 and 2004, the facility successfully fueled four large waste transfer trucks with 350 400-horsepower engines off and on. However, this application was halted when the engines were no longer being sold. Although the facility is still capable of producing 1,000 gasoline gallon equivalents of CNG per day, it currently produces only 1,000 gasoline gallon equivalents per month. Puente Hills has met with Cummins Westport and expressed interest in running a demonstration project for a large waste transfer truck if an engine becomes available.

EPA's Landfill Methane Outreach Program (LMOP) is promoting interest in converting landfill methane, a potential greenhouse gas, into a renewable clean transportation fuel. As this trend continues, companies that own landfills and refuse truck fleets will find initiatives such as the Burlington County project especially attractive.

So this has been done before and is technically feasible, it's just not clear if this is better than simply burning the waste gas for electricity. I look forward to following this area and seeing which reuse of trash becomes the more viable and energy efficient concept.

It would seem to me that a hybrid CNG trash truck would make the most sense, since they are probably the worst example of "stop and go" use I can think of the regenerative braking system really makes sense here to recover some of the energy required to accelerate all those tons of trash time and time again.
Hybrid drivetrains are being developed by Volvo trucks and heavy machines and Scania trucks for stop-and-go trucks, busses, loaders and so on.
In a low-energy future... efficiency becomes the prime consideration...

It will never make sense to burn ANY liquid fuel in an ICE at 30% efficiency >> throwing away 70% in the form of heat???

If we have a liquid or gaseous fuel... CNG; landfill gas, CTL... it will be primarily used as a chemical feedstock.

And if you did want to burn the fuel... then it would have to be in a stationary situation so that you can harvest the high-quality heat... for industrial process, space heating, water heating, greenhouses... whatever...

As for trash trucks... what better application for EV... frequent stop & start; no pollutants whilst idling, only low velocity needed... day-use only > over-night recharging

Hell, the British have had electric "milk delivery vehicles" going door-to-door for this identical role since way back in 1950s...

It also seems to me that a hybrid CNG truck would make a lot of sense for trash hauling. I'm fuzzy on whether current diesel engines can be converted to CNG like gasoline vehicles, but I do know that the Houston MTA runs most of its busses on CNG, but that these vehicles were purchased new. The buses are much cleaner and more quiet than diesel vehicles.
  The US gas situation is a heck of a lot better than the oil situation as far as supply. Most of the US sedimentary basins have only been explored thoroughly to 12,000 feet subsurface,and commercial production depths are now possible to 20,000 feet plus. Virtually all the oil is in the 2,000-10,000' depth range in wells, but the greater depth areas are prone to natural gas production. I think that we are still on the up slope in gas production as far as volumes.
  But costs go up exponentially as wells are drilled and completed at greater depths and in unconventional objectives such as coal bed methane and shale gas wells or in the deep water and subsalt plays offshore. And burning gas in vehicles still doesn't address global warming.
  Produced gas from organic wastes could have the CO2 captured and sequestered from both the upstream production and also from the exhaust of an electric generating plant in a much more cost effective manner through osmotic membrane technology,IMO because it has only one source.  
My wild ass guess is that even if you had to swap the engine for something else to make it wor on CNG it would be worth it

To John Milton,
Allow me to requote your paragraph, because it so correct....

"It would seem to me that a hybrid CNG trash truck would make the most sense, since they are probably the worst example of "stop and go" use I can think of the regenerative braking system really makes sense here to recover some of the energy required to accelerate all those tons of trash time and time again."

There are developments afoot that will astound you, then, but, surprisingly, they will be hybrids, but not gas electric style hybrids.  Due to the battery limitations, those are still half decade down the road for heavy vehicles.

But there is a better way.  Combined with CNG, the use of the Hydraulic Hybrid drive will enhance performance and efficiency.

And of extremely great promise, the stats and details on the EPA/Eaton Corp./Ford partnership demondstrated on a sport ute:

On many stop and go and vehicles, including mail and delivery trucks and vans, UPS delivery vans, school buses, city passenger buses, and of course, sanitation trucks, the improvement in efficiency once these designs make their way into the fleet nation wide will result in declines of tens of millions of gallons in fuel consumption.  It is a revolution that is long overdue.

Roger Conner known to you as ThatsItImout

As Engineer Poet has proved... pure electric is the only way for transportation. It whips HFC by an efficiency factor of 2; and as for the ICE... (hybrid or not) forget it...whether you are burning petrol, diesel or CNG... why throw away 70% of your liquid/gaseous energy to the atmosphere for what is just a low speed, multi-stop & start trip ?

Ok, so heavy duty EV is not ready yet... how much imagination does it take to get round the problem...  say, a fleet of small EV "cabs" pulling lightweight trailers to a central point.. drop & pick up an empty... go to the next subdivision... SOLVED.

And maybe while we are at it... we can start locating landfills for garden waste in the centre of town rather than every inhabitant having to drive(in my case 5 miles) out of town and there, join a line of trucks emptying their 10kg of grass cuttings...

Sorry... just venting...


Old hat? CNG (and LPG) have been used in vehicles in New Zealand (and probably Australia)@since the 1980s! While CNG has sort of disappeared (due to lower power output) LPG is still very popular and one would expect it to increase its market share substantially; especially since it is much cleaner running and price is less than half that of petrol. But as with any good thing, it seems that the Big Car are trying to discourage its use with many companies no longer offering an LPG tank option at the time of purchase! Of course you can modify your car at a later stage but they refuse to cover it under warranty! Go figure!

Anyway, in Kyoto (where I am based now) the city rubbish trucks have used cooking oil for the past 2-3 years, if I remember correctly. Also, another major contributor to city pollution, the bus fleet is slowly switching over to bio-diesel, although I am not sure of the exact combination of the alternatives they use. It is certainly a start because hundreds of huge buses belching out black diesel smoke has been an eyesore in Kyoto and other Japanese cities for years now.

i think a peak in natural gas should be looked at seriously
OPEC production down in July.0.8%.

Iran,Kuwait ,Saudi Arabia and Nigeria all down. The citibank analyst says "it is unusual to see so many members move in the same direction" Really? Get used it. Idiot.

This won't help much.

Major Alaskan oil field shutting down
By MARY PEMBERTON, Associated Press Writer 7 minutes ago
ANCHORAGE, Alaska - Half the oil production on Alaska's North Slope was being shut down Sunday after BP Exploration Alaska, Inc. discovered severe corrosion and a small spill from a Prudhoe Bay oil transit line.
BP officials said they didn't know how long the Prudhoe Bay field would be off line. "I don't even know how long it's going to take to shut it down," said Tom Williams, BP's senior tax and royalty counsel.
Once the field is shut down, in a process expected to take day, BP said oil production will be reduced by 400,000 barrels a day. That's close to 8 percent of U.S. oil production as of May 2006, according to data from the U.S. Energy Information Administration.
"We regret that it is necessary to take this action and we apologize to the nation and the State of Alaska for the adverse impacts it will cause," BP America Chairman and President Bob Malone said in a statement.
Malone said the field will not resume operating until the company and government regulators are satisfied it can run safely without threatening the environment.
Officials learned Friday that data from an internal sensing device found 16 anomalies in 12 locations in an oil transit line on the eastern side of the field. Follow-up inspections found "corrosion-related wall thinning appeared to exceed BP criteria for continued operation," the company said in a release.
That's when workers also found a small spill, estimated to be about 4 to 5 barrels. A barrel contains 42 gallons of crude oil.
BP says the spill has been contained and clean up efforts are under way. State and federal officials have been informed of the decision.
BP said it was sending additional resources from across the state and North America to hasten the inspection of the remaining transit lines. About 40 percent of the lines have been inspected.
BP previously said it would replace a 3-mile segment of pipeline following inspections conducted after up to 267,000 gallons of oil spilled onto the frozen ground about 250 miles above the Arctic Circle in March.
House Speaker John Harris said it was admirable that BP took immediate action, although it's sure to hurt state coffers.
"This state cannot afford to have another Exxon Valdez," said Harris, R-Valdez

Hundred dollar/bbl oil, here we come! Combined with the beating of the war drums for Iran
and Syria and hurricane season, and the collapse
of Cantarell, we are all in a world of poo.
It sounds like the Alaska pipeline needs replacement.
crude oil jumped about $1 on this news, so its meaningful, but not a crisis.

"It sounds like the Alaska pipeline needs replacement."

....yeah and they just realized TODAY, with no foreknowledge....


Roger Conner  Known to you as ThatsItImout

yeah, they alllllll peaked at once....this is getting rich!!

Roger Conner  known to you as ThatsItImout

In the city I live in, between 35 and 40% of all rubbish disposed of to land fill is composatble. Basically any  material which was once alive. The nutrient loop can be closed and those valuable nutrients returned to the foodchain by either composting or vermicomposting. My worm farm manufactured from an old refuse bin (250 L)disposes of every bit of food waste my girlfriend and I produce. We use the resulting juice for our pot plants and the dirt produced for our raised bed salad garden. Our worm population is big enough after 1 year to dispose of all of our food waste and all the weeds we pull from our garden. Needless to say I enjoy very fine salads every day. If everyone in NYC was encouraged to seperate their foodwaste for composting and dispose of it onsite if possible, or encourage communal composts where it is not possible to dispose of it onsite (Apartments) this would go a long way towards minimising not only oganic refuse to landfill, but the resultant methane entering the atmoshere...
Feeding the stuff to worms just turns it to CO2 without offsetting any other energy use (at least not directly).

Suppose instead that you carbonized that matter (turning it into charcoal and a combustible off-gas), then used the off-gas for fuel and the charcoal as half soil amendment, half feed for direct-carbon fuel cells.  All potassium and phosphorus winds up either tied up in charcoal or in recycled fuel-cell effluent.  You could knock out a considerable chunk of your energy needs this way (and even store it against future needs once it was dried).  Would you rather eliminate large parts of your fuel consumption and sequester a stream of carbon, or feed worms?

Great idea E-P! Have you prototyped it? Or know anyone who has?
Not really my idea; check the DCFC stuff in my reference library.
Folks, step right up and get in line to purchase your very own EnPoCo Ergosphere 250 LX home solid-oxide fuel cell with integrated solid waste gasifier and air liquifier.  For the introductory price of just $39,999.98 you to can own this amazing piece of technology and start burning your garbage and save!,,*

*Estimated to provide $200/year of energy savings with a payback period of 200 years.  Maintenance not included in calculations.  

**To be used with paper waste and food refuse only.  Products containing silanes such as conditioners, hand-lotion, and makeup are not to be gasified.

**Coproduct liquid nitrogen is not a toy.  

I was thinking more of a city-sized unit.  It would certainly reduce transport costs over e.g. shipping Toronto garbage to Michigan, or NYC's to North Carolina.

A sterile product such as charcoal would eliminate pathogen worries when used as a soil amendment, too.

Check this out!  BP is shutting down 400 kbpd from Prodhue Bay!

I understand the pollution advantage of CNG, but what is the fuel advantage. Does it really matter whether we produce the methane and sell it to others, or produce the methane and use it in our own trash trucks? This second reasons seems to be grasping at straws.

Pollution reasons seem good though.

The idea is to close the loop on a local energy demand and supply. If it's not feasible to do, I'm all in favor of selling the methane or burning it to generate electricity or whatever, but there is great value in basically taking garbage trucks, a critical municipal service, and insulating it from the price shocks that will inevitably occur.