SACRAMENTO, Calif. – Driving along I-80 just outside Sacramento, I’ve got the window down and my ears strained. I’m in a Volvo VNL day cab belonging to Texas-based Martin Transport with a D13 engine under the hood, mated to an...
SACRAMENTO, Calif. – Driving along I-80 just outside Sacramento, I’ve got the window down and my ears strained. I’m in a Volvo VNL day cab belonging to Texas-based Martin Transport with a D13 engine under the hood, mated to an I-Shift automated transmission. I’ve driven this truck before – or a reasonable facsimile – but this time something’s different.
The tanks mounted to the frame will tell you this truck is fuelled by dimethyl ether (DME). But try as I might to prove otherwise, from behind the wheel the truck drives, pulls and sounds just like a diesel. And that’s what Volvo loves about DME, and why it has been publicly pounding the DME drum since as far back as 2005.
While the North American trucking industry has come to equate natural gas with going green, along comes DME, which is in many ways cleaner, and potentially more energy-efficient than natural gas. DME is a manufactured fuel, which can be produced using virtually any methane-containing feedstock, including cow manure, grass clippings, organic food waste and even natural gas itself. On a molecular level, because there are no carbon-carbon bonds, the fuel burns exceptionally clean, producing absolutely no soot. This eliminates the need for a diesel particulate filter (DPF) and even cooled exhaust gas recirculation (EGR), as well as its associated EGR valves and coolers.
Volvo has been testing DME in Sweden and North America – but mostly Sweden – for several years now and has accumulated 650,000 miles of real-world testing. But it’s safe to say the industry’s trade journalists were surprised when it was announced June 6, in front of the California State Capitol building, that Volvo will bring to market a DME-powered truck in North America as early as 2015.
DME, commonly used today as a propellant in aerosol sprays, including asthma inhalers, is not yet widely available as a vehicle fuel. However, the impetus for Volvo’s announcement was a proprietary new, small-scale DME production method, developed by Oberon Fuels, which could produce DME at a customer’s own facility at a price that’s competitive with diesel. That got Volvo’s attention.
“Our small-scale process enables the utilization of regional feedstocks to produce DME,” said Rebecca Boudreaux, Ph.D., president of Oberon Fuels. “Cost-effective, regional fuel production addresses the distribution issue, and offers the potential to bypass the need for a national fuelling infrastructure, while reducing the carbon footprint associated with transporting the feedstock and the fuel produced.”
Oberon, whose co-founder and chief operating officer Elliot Hicks hails from Saskatchewan, is planning to build skid-mounted production units that can be delivered to customer sites for the production of DME using locally available feedstocks. The company’s business model involves building, owning and operating the production units, which will be available in 4,500 and 10,000 gallon per day versions, able to produce enough DME to fuel 60 or 150 trucks, respectively. The first of these sites are going online in Brawley, Calif. and Chicago, Ill. this month. A 4,500 gallon per day site would require about 100 tonnes of food waste daily, but it’s capable of producing smaller volumes, Boudreaux noted.
Oberon’s ability to cost-effectively produce DME for road transport was just what Volvo needed to take the next step towards commercializing DME-powered vehicles. Goran Nyberg, president of North American sales and marketing with Volvo, declared at the Capitol that “In 2015, Volvo will begin commercial production of DME-powered Volvo trucks in the US. This is a first for North America and a first for Volvo Group. Volvo is a pioneer in developing and testing DME as a viable fuel for heavy trucks and we feel very positive about the commercial potential in this market.”
Ed Saxman, marketing product manager, alternative fuels with Volvo, said the engine adaptation required to run off DME is actually quite simple. The D13 base engine doesn’t change drastically, with the exception of a new fuel system that will operate at much lower injection pressures.
“DME doesn’t make any soot, so we won’t need that very high fuel injection pressure,” Saxman said. “This engine design gets us back to basics. We are confident we can produce a reliable, durable engine out of the box with this low pressure injection.”
Customers won’t be sad to see the elimination of DPFs and EGR coolers, either. The DME design also does away with the seventh injector and could eventually eliminate selective catalytic reduction (SCR), though the early versions will likely be SCR-equipped.
Current DME prototypes being run by Texas-based Martin Transport – including the one I drove –have a range of 600 miles, which Saxman said was the target needed to commercialize the vehicles.
“We’re easily capable of putting enough fuel on the truck to do 600 miles, which we feel is the needed range,” Saxman said. The first DME-powered D13s will be rated at 425 hp and 1,750 lb.-ft. of torque, which is currently Volvo’s most popular rating. A 500-hp version will follow.
Comparisons to natural gas will be inevitable, since the trucking industry has been gravitating towards compressed and liquefied natural gas as the alternative fuels of choice. Fuel price and availability will continue to favour natural gas – and Volvo has no plans to abandon its natural gas product development – but DME addresses some of the shortcomings of CNG and LNG.
CNG and LNG-powered trucks can cost $30,000 to $90,000 more than their diesel counterparts, and much of that is attributed to the cost of the fuel tanks. CNG is stored on the vehicle at 3,600 psi and LNG at temperatures of -260 F. Both scenarios require heavy and costly double-walled tanks.
DME is stored at ambient temperatures at 75 psi, requiring a less expensive steel tank that’s similar to a propane canister. For that reason, coupled with the simplicity of the base engine adaptation, Volvo is confident it will be able to sell DME-powered trucks at roughly the same cost as conventional diesels.
With 69,000 BTU per gallon, DME has energy density comparable to LNG (about half that of diesel and twice the punch of CNG) and doesn’t boil off over time, like LNG.
“We can package DME on a truck with a shorter wheelbase and still have a greater range than either of the other two popular alternative fuels used today,” Saxman said.
DME may be the ultimate clean fuel. After all, Oberon’s manufacturing process takes methane emissions that would otherwise be released into the environment and locally converts them into an ultra-low-emission fuel. But even if both the truck and fuel are priced competitively with diesel, most fleets will want to see how DME can benefit their bottom lines, which is what makes natural gas so appealing, with fuel prices about 30% lower than diesel.
Saxman said there are many benefits to DME that could pay back over time. For starters, the price of DME won’t be tied to crude oil, so users will be protected from the volatility of diesel prices. Fleets that make their own fuel won’t have to worry about how wars in the Middle East – or for that matter, refinery fires in Alberta – will influence their access to fuel.
DME may also appeal to fleets – private or for-hire – that want to run the cleanest fuels possible to reduce their environmental footprint. However, the biggest bang for the buck may go to carriers that have ready access to feedstocks.
For example, a fleet that transports municipal waste to a landfill or a grocery chain that delivers product to stores where there’s an abundance of expired food that can be converted to fuel. Dairy fleets in rural areas, cattleliners delivering to feedlots, refuse trucks in major cities – there really are plenty of applications where DME makes sense from both an economical and environmental perspective.
In the US, grocery giant Safeway has already agreed to pilot the next batch of DME trucks Volvo builds, using fuel that Oberon will produce for it at locations in the San Joaquin Valley.
Jonathan Mayes, senior vice-president of government relations, public affairs and sustainability for Safeway, said, “Our company continues to look for innovative ways to reduce our carbon footprint. Converting to a cleaner burning, renewable fuel such as DME presents a good opportunity. We are pleased to be working with Oberon Fuels and Volvo Trucks on this first-of-its-kind trial in North America.”
Because it has been thoroughly tested in Sweden, DME has been run in Canadian-type conditions and Volvo officials said it thrives in cold weather, with no gelling. And Saxman pointed out that bacterial growth and algae formation, occasionally problematic in diesel storage tanks, aren’t an issue either.
There’s a lot to like about DME, including from the driver’s seat. On my drive around Sacramento, it lived up to its promise of delivering diesel-like performance, sound and feel, both at highway speeds and in stop-and-go traffic. I was grossing about 55,000 lbs with a gravel-filled belly dump in tow.