With no miracle fuel on the horizon, truck makers weigh near-term alternatives to standard diesel.
If there is such a thing as a Holy Grail in the world of alternate fuels, it would be hydrogen. It is truly a miracle fuel: Cheap, safe, abundant and – since it’s mostly water atoms – renewable.
But while hydrogen may show promise as a fuel of the distant future, alternate fuels we’re likely to see in the near term will, for the most part, depend on some percentage of fossil fuels to work properly. But global factors now are trending against cheap and abundant petroleum-based automotive fuels.
Andy Douglas, national sales manager of specialty products for Kenworth Trucks, says the truck maker has been working closely with Boone Pickens. “He’s a firm believer that oil production capacity is not going to get a whole lot larger,” Douglas says. “Demand is going to outstrip it – particularly world demand coming out of Asia. So we’ve got to figure out another way of doing some things. And I think we’re there.”
The challenge for truck and engine manufacturers is two-pronged: What can they do in the near term to ease environmental concerns and help a fleet’s bottom line, and what can they do in the long term to end our dependency on fossil fuels permanently?
A big part of the challenge, experts say, is that diesel is unfairly maligned in some quarters. It’s high in power density, making it efficient compared to other fuels, and – thanks to low-emissions diesel technology – has turned into one of the cleanest fuels now in existence. Truck and engine makers often argue that when the next generation of clean diesels enters the market in 2010, diesel trucks will serve as mobile air scrubbers, since their exhaust emissions may be cleaner than the air they draw into engines in the first place.
“In the near term, our choices are fairly limited in terms of what we can do,” Douglas admits. “Long term, we’re working every day on things you’ve heard of – like hydrogen – and things you haven’t heard of. And there’s a lot of ‘man in the moon’-type technology out there that may never pan out for us. So the intense focus now is on technologies and fuels that we can produce in relatively high qualities and bring to the marketplace quickly.”
Detroit Diesel is working to develop engines that burn less while also burning cleaner. “For urban mobility, we see an opportunity for natural gas to become a commonly used fuel,” says David Siler, marketing director. “For more all-around and long-haul activity, Detroit Diesel sees opportunity with not only current generation biodiesel fuels, but also the next generation of biodiesel,” also known as BTL (biomass to liquid or synthetic) diesel fuels.
Working with its Daimler partner companies, Detroit Diesel sees promise with SunDiesel as a strong contender to reduce emissions of particulate matter, carbon monoxide and hydrocarbons, while converting wasted biogenic matter into synthetic diesel fuel, Siler says. “This technology would not compete with food crop cultivation and would not require engine equipment retrofitting,” he says.
While there may be a lot of uncertainty in the marketplace now as to what, if anything, will ever truly replace diesel fuel, Douglas does know this: “We’re in a nice little lull right now with oil. But my sense is this is the calm before the storm. Sooner, rather than later, we’ll be back to where we were with $5 diesel at the pump, and eventually prices will go higher. So we really don’t have a choice. We’ve got to do something.”
Betting on biodiesel
Near-term alternatives to petroleum typically have one thing in common: Fossil fuel. Liquefied and compressed natural gas (LNG and CNG, respectively) are fossil fuels, and so, in part, are biodiesel and ethanol – unless they are 100 percent, which they typically aren’t today. None of these alternative fuels have the same power density as conventional diesel fuel, however.
So simply finding alternative fuels isn’t enough, Zahn says. “We have to find new fuels that can deliver performance on par with diesel and gasoline. Market demand will define the fuels of the future.”
By any standard, biodiesel has been an early winner in the race to find viable alternative fuels. Biodiesel typically is produced from standard animal feedstock such as soybeans, rapeseed and palm, and there are efforts to use “waste” plants and animal fats for biodiesel.
When refined, soybeans and other plants yield fatty acid methyl esters, says Greg Shank, coordinator of lubricants, fuels and coolants technology for Volvo Powertrain North America. Fatty acid methyl esters can be blended in various quantities with conventional diesel fuel, Shank says; up to 20 percent biodiesel has been approved for use in some North American engines.
Some biodiesel users have reported slightly reduced engine performance – about a 5 to 10 percent energy loss – compared to engines burning straight diesel fuel due to biodiesel’s lower energy density, Shank says. “Biodiesel is solvent, and therefore corrosive to certain materials and components inside an engine, so users will see an increased need for maintenance,” he says. Additionally, higher nitrous oxide emissions are possible. “We’re now examining biodiesel’s impact on diesel particulate filters.”
But all told, Shank is a biodiesel fan. “It’s currently available, and that’s a big plus,” he says. “It offers almost equal operational range to nonblended diesel fuel and requires only minor vehicle adaptation requirements.” But Shank believes the industry must adopt a common standard for biodiesel formulations and blends. “I think that’s a relatively minor obstacle to overcome.”
Zahn agrees that biodiesel remains a good solution from a domestic availability standpoint. “Octane boosters can help with its lower energy density,” he says. It does produce more NOx, which is a leading contributor to smog, so the benefit is split. “It also is prone to absorbing water, so potential algae growth needs to be closely watched. But, again, additives are available for use to control any algae growth and keep fuel clean.”
Cleaner, complicated natural gas
From the standpoint of the environment, natural gas is among the best near-term alternatives. Comprised mostly of methane with carbon being only one-fifth of its makeup, it is an inherently clean-burning fuel that leaves almost no soot behind after combustion.
But natural gas has its detractors, since the fuel is hard to ignite and there are onboard storage issues for trucks. As a vehicle fuel, natural gas can be either compressed (CNG) or liquefied (LNG). While CNG is compressed like the air in a scuba tank, LNG is stored at a cool -260 degrees Fahrenheit, in super-insulated tanks that resemble large Thermos bottles. Since LNG must be vaporized prior to combustion, the only real difference between LNG and CNG systems is in the fuel delivery hardware. In either case, the fuel mixes with air at the throttle body and is ignited by a spark plug at each cylinder.
Also, because the natural gas infrastructure is so immature, it currently is suitable only for fleets that return regularly to a home base within reach of city gas mains. Natural gas currently is as much as 40 percent cheaper than diesel fuel, but skeptics point out that natural gas is not subject to federal or state highway taxes. Taxing natural gas could reduce the operational cost advantages.
Cummins Westport, a joint venture between Cummins and Westport Power, has been producing LNG ISX diesel engines for several years and is a passionate proponent of natural gas in trucking applications.
Westport takes standard Cummins ISX engines and equips them with highly advanced injection systems. Medium-duty Cummins Westport diesel engines also include a spark-ignition system and a different combustion chamber to help facilitate optimal performance. Fueling the trucks is fast: Both saddle tanks can be filled via a single connection on one side of the truck.
The tanks store the fuel without a significant pressure increase, although if left idle for seven to 10 days in warm weather, they may vent a small amount of gas. The tanks have been tested to withstand impacts equivalent to a drop from an eight-story building, says Tony Picarello, Westport’s vice president of heavy-duty sales and marketing; in the event of a rupture in a crash, the lighter-than-air gas rapidly rises skyward, making an explosion unlikely.
Picarello believes natural gas engines suffer from an image problem. Old-model natural gas engines limited efficiency and reliability of medium- and heavy-duty vehicles, he says, but today’s technologically advanced high-pressure direct injection systems allow engines to operate with diesel efficiency, power and torque. “We’ve conducted numerous field trials and demonstrations to prove technology advances.”
Customers include the ports of Los Angeles and Long Beach, which plan to spend $1.6 billion on Kenworth T800s equipped with Westport natural gas engines as part of their Clean Trucks Program. Also, Pacific Gas and Electric in San Francisco is the nation’s first utility to operate T800 LNG-powered trucks.
Kenworth’s Douglas believes that at the end of the day, “it’s going to be a little bit of everything” that fuels future trucks. “I’m fully convinced there’s a place for plug-in electric and natural gas, and diesel-electric hybrids and something running on swamp water,” he says. “It’s going to take all of that – and more.”
2-million-mile biodiesel test passes halfway point
Biodiesel has caught the eye of Americans everywhere, from famous Outlaw Country singers to patriotic good ‘ol boys running their rigs from coast to coast. The appeal is a natural one: Get American farmers to grow feedstocks that can be blended with diesel fuel, thereby stimulating the farming industry and reducing our dependence on foreign oil at the same time. Biodiesel reduces the carbon footprint of a diesel engine, and any CO2 it emits eventually will turn into oxygen and sugars during later growing seasons.
Despite the biodiesel buzz, its use has raised some red flags in the trucking industry – mainly gelling issues in cold weather and slightly higher NOx emissions than conventional diesel engines.
Some of these concerns are being addressed by a 2-million-mile biodiesel study conducted by Fort Dodge, Iowa-based Decker Truck Line, which runs more than 700 trucks and 1,400 trailers, with nine terminals in five states. Third-generation trucker Dale Decker, the company’s industry and government relations director, found out about biodiesel several years ago. The more he learned, the more he wanted to try the fuel in trucks. “I appreciate the fact that biodiesel provides support for American farmers as a homegrown fuel,” he says.
Decker Truck Line is the first major trucking company to compare a soy biodiesel B20 blend to regular petroleum diesel in a comprehensive over-the-road test covering 2 million miles. With about 400,000 miles left to go in the two-year demonstration being conducted in the upper Midwest, the head-to-head testing showcases positive performance effects and valuable cold weather findings, the partners say; data collected from each truck’s electronic data recorder this summer shows fuel efficiency for the B20 blend comparable to that of petroleum diesel.
“In recent months, we have learned that driver variability makes more difference in fuel efficiency than biodiesel utilization does,” says Dr. Don Heck, coordinator of biotechnology and biofuels programs at Iowa Central Community College in Fort Dodge, where Two Million Mile Haul test data are analyzed.
“This new information is exciting because we already know that biodiesel offers a fleet many added benefits beyond fuel efficiency,” says Grant Kimberley, Iowa Soybean Association director of market development, who helped coordinate the program. “Biodiesel acts as an engine lubricant. Biodiesel offers significantly higher cetane numbers, reduces harmful emissions and adds national fuel production, and biodiesel offers a fleet the opportunity to market itself as a ‘green’ transporter to today’s environmentally conscious corporations.”
In addition to fuel-efficiency data, the Two Million Mile Haul aims to demonstrate operability of a B20 blend year-round in cold weather situations. “Although both the petroleum and B20 groups experienced some fuel-filter plugging in zero-degree Fahrenheit weather, the B20 trucks did not experience any considerable challenges because test partners implemented proper handling and storage measures,” Kimberley says. “If B20 can work for a fleet in the upper Midwest from December through February, it can run in any fleet across the nation year-round.”
The partners say these findings mimic fuel-efficiency test results released in July by the National Renewable Energy Lab and the National Biodiesel Board, showing comparable mileage between B20 and ultra-low-sulfur diesel. “Fleet owners, fuel managers and owner-operators can be confident about biodiesel utilization in their over-the-road operation because of the results of the Two Million Mile Haul demonstration,” says Tom Verry, National Biodiesel Board director of outreach and development.
There also may be additional benefits for a trucking company using biodiesel. “We are receiving positive feedback from customers who see the ‘green’ benefits of using a trucking company that runs on biodiesel,” says Steve Lursen, special projects manager for Decker Truck Line. “By using a renewable fuel, Decker is actually picking up additional business.”
The two-year study is sponsored by the Iowa Soybean Association, Iowa Central Community College, Decker Truck Line, Caterpillar, the National Biodiesel Board, Renewable Energy Group and the U.S. Department of Agriculture. The study, which began in fall 2006, consists of two groups of 10 Decker semi-tractors running with flatbed trailers on matched routes to either Minneapolis or Chicago. The control group uses 100 percent No. 2 petroleum diesel, and the B20 test group uses a blend of 20 percent biodiesel from Renewable Energy Group and 80 percent No. 2 petroleum diesel.
