San Diego-based Oberon Fuels has been developing a new alternative fuel for the heavy duty trucking industry. Called dimethyl ether (DME), the fuel is clean-burning and non-toxic with diesel-like performance and handling properties similar to that of propane. As the first company to produce fuel-grade DME in North America, Oberon is hoping to bring this fuel, made from natural gas or biogas, to the solid waste hauling market.

With no commercial or passenger vehicles with DME-capable engines and no network of fueling stations, Oberon, led by President Rebecca Boudreaux, has developed partnerships with automakers Volvo and Ford to develop DME engines, and has led the certification process for the fuel with the EPA, state of California, Department of Energy and ASTM.

Officials in California certified the new automotive fuel for use in the state last year, giving it a push as the latest innovation in the alternative fuels space. The company also has reached out to commercial fleets and city managers to drive demand for fuels and engines.

“For waste haulers in particular, what we hear is that there is still a gap between companies that want, or are required to, reduce emissions and the ability of current alternatives—electric and CNG—to provide the power and torque needed. DME fills this gap and we and our partners are committed to bringing this new option to fleets in the U.S. and around the world,” says Boudreaux.

But given the success of compressed natural gas (CNG) and liquefied natural gas (LNG) in the waste industry, does DME stand a chance?

“The key driving force for DME is its simplicity—simple fuel, simple engine, simple infrastructure,” says Boudreaux. 

According to Boudreaux, DME generates no particulate matter, low NOx, is sulfur-free, and can be made from a variety of methane and carbon dioxide sources like food, agricultural, wood and animal waste. Because DME contains no carbon-carbon bonds, DME produces no particulate matter and thus requires no diesel particulate filter (DPF).

“Without the DPF, it becomes simpler for engine OEMs to treat other criteria pollutants such as NOx, reducing the after-treatment required on a vehicle,” Boudreaux says. “Compared to a spark-ignited engine used with CNG, DME engines provide higher torque, longer range, shorter fill times, and more flexible and efficient chassis designs.”

Like propane, DME is a gas at ambient conditions. It becomes a liquid with only about five bars of pressure. It fuels as a liquid and offers diesel-like fill times for demanding freight duty cycles.

Boudreaux says the key to DME market penetration is not only lower fuel cost but a lower total cost of ownership—fuel, vehicle, maintenance, and infrastructure—compared with diesel and other alternative fuels.

DME can be made from a variety of waste feedstocks—food waste, grass clippings, agricultural waste, wastewater treatment gas, and landfill gas.

“As cities and states write increasingly stringent regulations for diverting organic waste from landfills, waste haulers and processors need options for that diverted waste,” she says. “Converting waste to biogas which can then be converted to DME provides opportunities for waste haulers to obtain a locally-produced, resilient, and clean, low-carbon fuel for their fleet—including the heavy-duty trucks used to transport consolidated waste from material recovery facilities to processing plants. As diesel prices inevitably rise from today’s lows, DME provides a flexible fuel for all duty cycles, and with the ability to negotiate stable, predictable pricing over the long term.”

DME vehicles use a standard base diesel engine with a modified DME fuel system.

Oberon's challenges are, like any alternative fuel, educating customers about the benefits of DME, gaining early traction, being cost-competitive as it scales to large volume offerings, and ensuring the right regulatory framework is in place to deal with a new fuel.

Oberon currently is providing fuel-grade DME to the Volvo Group for its North America-based testing of Class 8 heavy-duty trucks and to Ford’s Germany-based project building world’s first DME-powered passenger car for on-road testing.