Although interest in alternative fuels has cooled down a bit as diesel prices have dropped, supporters of dimethyl ether, or DME, still believe the alternative fuel has a bright future.

DME is a methane-based fuel that burns clean and can be derived from a variety of sources, from natural gas to agricultural waste products. It functions similarly to propane for engine conversion and storage purposes, but delivers a similar power performance to diesel.

Volvo Trucks North America so far has been the biggest supporter of the fuel in the U.S., developing DME for commercial use with Oberon Fuels and working to build infrastructure and engines to take advantage of the fuel.

However, last fall it announced it would no longer project a date for commercial availability, citing a slowdown in the pace of the North American alternative fuel market.

Volvo said it would continue to field-test its DME powered vehicles, but the company decided not to set a date for commercialization "as it monitors market and stakeholder interest in the fuel."

Volvo has been conducting a pilot program with Martin Energy Services and Oberon Fuels to bring the fuel to the commercial vehicle industry.

Ironing out the bugs

At the Mid-America Trucking Show, a DME-powered truck was lacking from the Volvo booth. When asked about it by reporters at a press conference, Frank Bio, Volvo Trucks director of sales development, specialty vehicles and alternative fuels, said the DME project was "still alive. We're still actively working with the State of California and also internally still developing DME," he explained.

"The reason we took the introduction date off the table was that we recognized we still had some challenges with distribution and some technical things, that can be solved very easily."

In an interview with Truckinginfo last fall, we asked Elliot Hicks, co-founder of Oberon Fuels, about the pilot program. "Volvo had done all of their development work on DME in Sweden. When they brought over trucks to work with Martin, it was the first time they converted to a North American duty cycle and set up of the truck.

"Naturally with any switchover there are issues to iron out, so it’s been very valuable in that it was the first effort to get the trucks over to North America and get them converted," he continued.

"Overall, it’s been very successful in that we’ve been getting good mileage out of the trucks and the drivers have been very happy with the performance of the trucks. The fuel that we’ve been producing has worked well with the vehicles.

"We have a couple of years before commercialization is finalized, but at this stage we’re quite happy with the performance of the tests," he added.

Long-term play

In an interview at MATS with Truckinginfo, Oberon president Rebecca Boudreaux called DME "a long-term play."

The advantage of DME, she explained, is its simplicity. It's one simple molecule and it can be made from a variety of sources. Unlike natural gas, it does not need to be put under very high pressure or cryogenic storage for use on a vehicle. And, she said, it's "true compression ignition," not needing spark plugs or piloting with diesel fuel as some natural gas engines require. That means less costly vehicles and fueling infrastructure.

She echoed Volvo's Bio, noting that "from an infrastructure standpoint, we want more companies doing it," saying, "we are continuing to make steady progress as well as on technical issues."

"In the last six months we have seen a surge in OEM interest," Boudreaux said. Achates Power, which is developing an opposed-piston engine, is testing it with DME. Oberon hopes to have another announcement soon on a deal with another OEM.

"We need multiple players on the engine side and multiple players on the infrastructure side," she said.

Approvals

Meanwhile, Boudreaux said recent approvals of DME as a vehicle fuel from the Environmental Protection Agency and California officials "are a key step in increasing confidence among distributors, engine manufacturers and fleet owners that DME is ready for commercial markets."

Late last summer, the EPA approved Oberon Fuel’s biogas-based dimethyl ether as meeting the agency’s Renewable Fuel Standard, helping clear the way for it to be an alternative fuel for trucking.

The agency determined that biogas-based DME produced from the Oberon process resulted in an approximate 68% reduction in greenhouse gases when compared to baseline diesel fuel, according to the company.

In February, California officially approved DME for use as a vehicle fuel.

Boudreaux predicts we will see DME trucks in significant volume within the next three years. California's more stringent emissions standards and low-carbon fuel requirements may help pave the way. "Gov. Brown has been very vocal about reducing dependence on petroleum," she said.

Despite the lack of a Volvo DME truck on display at the show, Volvo Group chief Olof Persson, in remarks to a supplier audience at MATS, said that although Volvo sees natural gas fuel as “continuing to play a role in some segments of this market – particularly in certain vocational applications and shorter, regional haul … when it comes to other segments, particularly longer hauls, we continue to believe DME shows tremendous promise.”

That’s because the conversion of natural gas into DME can “address many of the distribution, storage, and fueling challenges otherwise presented by natural gas – particularly liquefied natural gas – as a heavy truck fuel. If the industry were able to get the critical mass of production volume we need, DME could really be a game-changer.”