Greening the Fleet
Landfill gas powers CNG garbage trucks.
It’s not quite the Mr. Fusion from Back to the Future II, but Rumpke of Ohio’s newest fleet of garbage trucks does indeed run on garbage. The Cincinnati-based landfill operation invested $2.3 million along with an $800,000 grant from Clean Fuels Ohio in order to put 10 new compressed natural gas (CNG) trucks on the street last August. The grant was part of the original, national stimulus package. The project includes the CNG-powered refuse collection trucks and the construction of a natural-gas fueling station at the landfill. Much of the gas comes from Rumpke’s landfill-gas (LFG) recovery system that provides gas to 25,000 homes in Cincinnati in a partnership with Duke Energy, which provides local gas and electric service.
The program is a pilot study that was set up to determine how feasible it might be to use CNG vehicles as permanent additions to the Rumpke fleet, which has more than 1,700 garbage trucks in service across Ohio, Indiana, Kentucky, and West Virginia. Rumpke is tracking fuel economy, reliability, and performance of the new vehicles. The cab-forward, rear-loading trucks are marked with large, red stickers declaring, “Clean and Green Technology at Work.” But other than that, and the cabinet, located between the cab and the compactor, that contains the CNG tanks, they don’t look or sound much different from standard diesel vehicles.
“We’ve seen very good results in the first five months,” Rumpke spokesperson Amanda Pratt says. “We have budgeted to add 10 more rear-load CNG garbage trucks. We will also add one CNG front-load truck.”
The eleven additional trucks are slated to be on the road by mid 2012. The vehicles are built by International on a Mack LE chassis with a McNeilus 25-yard rear-loading body and a Cummins engine. Pratt explains that Rumpke normally services its public garbage routes using an International 7400 with a Class 7 chassis, but the CNG upgrade required a larger chassis to accommodate the additional weight of the CNG engine and tank systems. The LE chassis is a Class 8. The CNG option costs an additional $50,000 for this configuration, above the $209,000 price tag of the Class 7 vehicle. The CNG tanks carried onboard the trucks can store natural gas that is equivalent to 60 gallons of diesel fuel, enough for 10 hours of work.
Rumpke Route Supervisor Paul Rosselot operates one of the new trucks and says they smell different from diesels.
“It’s cleaner,” says Rosselot. “You don’t get that haze that hangs around. I like that a little better. Does it sound different? Maybe a little. There’s a little more of a gurgle to a diesel. As far as the power train, the torque, everything’s pretty much the same, except the engine.”
Rosselot describes the fueling process as similar to using an air compressor. It takes time for the pressure to build in the tanks. There’s a safety valve that’s closed during refueling, cutting the feed to the engine and an electric cutoff switch that’s flipped, too. Particulates in the gas are trapped by a filter before they can get to the engine. Rosselot says he likes how simple the exhaust is on the vehicle, in comparison to complex diesel filtration setups.
Rumpke driver trainer Dave Weisinger says the CNG trucks are as safe and possibly safer than diesel trucks.
“One of the things we do from the safety side is we take these to the local fire departments,” Weisinger says. “We don’t want them to encounter one of these on the route, stand back from it, and not know what to do.”
The tanks that hold the natural gas are wrapped in carbon fiber material and housed in a steel cabinet built by McNeilus, and the cabinet is reinforced with carbon fiber. This housing is positioned just behind the cab and above the chassis.
“McNeilus has actually taken these trucks and simulated various accidents that may occur to check the structural integrity of the cabinet, and it hasn’t been compromised in their tests,” says Weisinger. “Each fuel tank has its own separate shutoff valve, and our drivers are told, if they smell a fuel leak for any reason—because natural gas, whether we buy it from Duke or get it from the landfill, will have mercaptan, the odorant—should they smell that odorant, immediately shut down the truck, get away from the truck, isolate the area and call 911.”
But the emergency call is probably just a formality. Weisinger says he’s been told that when leaks occur, which is rare, the most typical area for leaks is at fuel line fittings inside the fuel tank cabinet. If a leak were to happen, the event would likely be over before it started: “We’ve been told by both McNeilus and Cummins that the tanks are so pressurized that by the time you shut the truck down, walk away from it and pick up the phone, the event will be over. The event will be over that quick.”
And once the fuel is released into the atmosphere, it dissipates quickly, so a flashpoint is a non-issue. “They’re probably safer than a diesel truck, because if this tank ruptures, the event’s over. If we’ve got 75 gallons of diesel fuel and the integrity of that tank is compromised, we’ve got environmental concerns, fuel on the ground, all types of issues there.”
Pratt says that having these trucks in service is the culmination of years of work and planning. In accordance with Environmental Protection Agency (EPA) requirements to dispose of LFG, Rumpke contracts with Montauk Energy Capital to operate three methane recovery and processing facilities. The first was opened in 1986, followed by another in 1995 and a third in 2007. About 15 million cubic feet of LFG can be recovered every day using these facilities, which, says Pratt, makes it the world’s largest LFG-to-direct-pipeline facility. (These are different than facilities that generate electricity using LFG, but may distribute that electricity to more homes.) Building on this was the opening of a new, 40,000-square-foot vehicle maintenance center in 2008. The $8 million structure was built with electrical, heating, and ventilation systems that were designed with CNG vehicles in mind. Methane sensors are located throughout the structure, duct work is insulated to minimize surface temperature, and all electrical elements are placed at least 18 inches from the ceiling. All of this is to ensure a safe work environment when servicing CNG vehicles.
The slow-fill fueling station and stands were added in 2011 along with the CNG trucks. At present, they can accommodate up to 16 trucks with room to expand to up to 50 more. Refueling takes around six hours if all ten trucks are hooked up to the lines and can take as little as 15 minutes if just one is refueling.
The LFG-to-CNG fuel operation appears to sprawl at first glance. The landfill produces the methane, which is captured by the gas recovery system, which consists of the three gas plants that purify the methane and convert it into natural gas. Then, the natural gas moves through Duke Energy’s lines and on to the slow-fill compression station, which is the first hit on Duke’s lines. From the fuel station, which has several stages of compression, ramping the pressure up to 800 pounds of pressure, is a line to the fueling stands.
Pratt says, although there is a learning curve for all of the new technology that required several days of training for Rumpke employees, there’s a good reason waste companies around the country are moving toward CNG: “There’s so many people in the industry that are seeing such positive results and it’s such a win-win for the environment and from a diesel cost perspective. They cost about half the amount for the gas.”
Pratt says the slow-fill setup works well for her company’s purposes. It’s standard for the trucks to sit at night anyway and fuel is the cheapest at this time. She says it can surprise people that Rumpke is both a natural-gas producer and consumer.
|There’s a safety valve that’s closed during refueling, cutting the feed to the engine.
“Although we recover the methane from the landfill and it goes to our gas plant and it’s converted to the natural gas, there’s not direct piping leading from our plant over to our CNG station—yet,” says Pratt. “We hope to do that in the future. The reality is we don’t own the gas from our landfill. We subcontract that out to a company called Getty Synthetic Fuels.”
Getty owns the gas as it is extracted from the landfill and sells it to Duke Energy, which distributes the gas to local homes and businesses.
The process is similar to the way solar panels are used on homes: Instead of keeping a battery in your own house that you charge every day, you feed back into the grid and draw from the grid, using the grid as a battery.
“Right now we’re the first hit on the lines coming from the landfill gas,” Pratt says. “From the natural-gas plant, the gas goes straight into duke’s lines. Our CNG station is one of the first hits on those lines. So truly we are getting the gas from the landfill to fuel these trucks, but we want to make it more direct in the future by building direct pipelines across our site. It’s happening, it’s just, logistically, it could happen better.”
So it’s not quite the Mr. Fusion, but it’s in the ballpark.
“From our standpoint, we’re focused on different ways to make our waste reusable or recyclable,” Pratt says. “We were already taking the renewable energy from the landfill, so this is just the next step. It’s an environmental protection effort, it reduces greenhouse gasses, it reduces our dependence on foreign oil, and at the same time it has a great economic benefit.”
CNG From Standard Gas Makes Sense, Too
Of course, large companies like Waste Management have made significant inroads into landfill-gas-to-energy operations and CNG truck use. But Rumpke’s work shows that it’s economically feasible for a regional waste management company like Rumpke to get in the game of cradle to grave upcycling of LFG. For smaller companies, like Ace Sanitation in Minneapolis, LFG may not be an option, but CNG trucks still make sense.
Ace Sanitation General Manager Mike Berkopec says his company operates a fleet of 55 trucks around the northern suburbs of the Twin Cities.
“We’ve been around since 1955 and have seen a lot of different changes so this whole thing was about us moving to the next level,” Berkopec says. Ace Sanitation’s first three CNG trucks will be on the road this year.
Berkopec concedes that the trucks are slightly more expensive than the upfront cost of a diesel, and the new fueling station Ace has built was just under $1 million, but says he’s hopeful the technology will pay for itself in the near future. The maintenance costs associated with new diesel trucks that meet current EPA requirements were a major factor in Ace’s decision to move to CNG.
“When we looked at that emission system we said, ‘Wow, there’s a lot of things on here and a lot of things that can go wrong,’“ Berkopec says. “There’s a certain way these things have to run including the burn off of exhaust. Although the CNG trucks are going to be more expensive, long term we’re hopeful they’re going to be better from a maintenance perspective because they’re simpler than the 2010 emission compliant diesels. The older diesels are obviously simpler. But these newer diesels, that kind of helped put us over the hump a far as making a decision. We’re hoping long term that the new CNGs are going to be a little bit better. From a maintenance perspective, there’s less that can go wrong on them.”
Berkopec says a lot of where the technology will go, as he sees it, depends on the prices of diesel and natural gas.
“In the short term, the payback is hard to see,” he says. “Especially as it depends on where the price of diesel and the price of natural gas goes. That, to us is the big unknown. Those are the big assumptions. It really depends on what those numbers are going to do. Obviously, if we’re going to make close to a million dollar investment in the station we believe that the differential is going to be there, that it’s going to be there to do CNG.”
Berkopec says Ace has to time the fueling of its CNG trucks not just when the prices are low, but also to avoid peak gas usage times for a practical reason. In Minnesota, when it gets really cold, the demand for natural gas goes up, and the gas company can’t pump enough natural gas to meet the demand. A peaking plant compensates for this by injecting propane into the line. Home heating systems can handle a certain amount of propane, says Berkopec, but CNG trucks can’t.
“There are cases, due to line pressure or this peaking thing, where some sites just aren’t good places to put a CNG facility, which is to me a barrier,” says Berkopec. “There may be times where we can’t get gas, so we have to plan for that.”
Because of its location, Ace isn’t using LFG. It’s not close enough to a landfill to make it work. Berkopec says Ace made the choice to buy the CNG trucks because it’s good business. He says that the new diesels are clean, but no longer that practical.
“When it first started, people said we’re going to do it because we’re greener,” Berkopec says. “They were going to greenwash it. I don’t really think that’s the case any more. I think it’s more of a business decision and that we’re trying to get out of the foreign oil problem. We’re going to market these as reducing our reliance on foreign oil and that they are quieter.”
Berkopec says he is concerned that if fracking technology is banned, it may cause a spike in gas prices.
“That to me is probably the biggest risk,” he says. “If that technology gets restricted that’s really going to put a wrench in this whole thing.”
Price Gap Narrows
Veolia Environmental Services Director of Business Chad Mark says his company has 56 CNG vehicles on the road and has two fueling stations operational: one in Fort Myers and another in Chicago. Veolia will have 49 more CNG trucks hauling trash and two more fuel stations working by mid-2012 in Madison and Evansville, IN.
“Our current strategy has been to find a location, build the infrastructure and then place the vehicles at that site,” says Mark. “I get calls frequently from companies that want to invest in the infrastructure themselves and then have us commit to converting our fleet and buying fuel from them.”
But it made the best economic sense for Veolia to build its own stations. Mark says Veolia expects the recoup its investment in CNG over about five years.
“Let me put a caveat on that. The calculations were quite complex,” Mark says. “There were a lot of assumptions made. One of them was we have to buy or replace a vehicle no matter what. So every year we have to replace a portion of our fleet in order to maintain our maintenance costs going forward. We keep our trucks 8 to 12 years. That’s one of the key assumptions and it’s a very big key assumption. The base truck itself, let’s say it’s $275,000, we’re talking about the additional cost being about $35,000 for CNG. So all of our payback analysis is based on that we already have to buy the truck, we have the choice of buying diesel or CNG. I look at payback analysis as the additional cost of CNG, and it does include the station. The complications come in depreciation. How long do we depreciate it? Is it over the life of the contract? Is it 10 years, 15 years, 20 years? All those are variables that our finance team puts in place when the project goes live, so it’s not quite an easy question to answer.”
All are of Veolia’s current CNG fleet is a cab-over design. He says they’ll also add some rolloff trucks this year, two in Madison and eight in Evansville.
“The drivers love them, aside from a little bit of additional heat down in Florida. That’s a problem or challenge a few months out of the year, when it’s really hot, but other than that we can keep them cool with the air-conditioning system,” Mark says. Because the CNG trucks burn hotter than diesel, there’s more radiant heat, and this affects driver comfort.
“They like them because they’re quiet and, of course, they’re brand new and they run,” Mark says. “Frankly, we’ve had a long list of issues with most recent releases of diesel engines with all the emissions requirements. These trucks, when you start them they run. There’s a very simple after-treatment system on the engine versus the diesel, which now has a complex after treatment system.”
Mark says CNG makes a lot more sense now than even just a half-decade ago. He says the cost difference might have been as much as $30,000 more four years ago than it is today. Since then, the diesel cost has risen considerably because of the EPA’s exhaust emissions requirements.
“So now the diesel trucks got $20,000 to $30,000 more expensive, which trumped that gap,” Mark says. “With that shrinking of the gap, we had dramatically increased problems. Trucks not running, getting clogged, shutting down on the road. Our failure rates on the diesel trucks have been unbearable. I think if you ask other guys, it’s universal. We’re all having problems with 2007 emissions trucks. I think every truck fails just about, and it fails often. They probably spend as much time in the shop as they do on the road, which is a problem for a $300,000 asset.”
Author's Bio: Cincinnati-based writer Stephen Novotni specializes in technology and energy.