Elliot Hicks is one of the co-founders of Oberon Fuels, a company that is exploring the production and use of dimethyl ether, or DME, in heavy duty trucks. He has a background in mechanical engineering and is tasked with addressing the issues of bringing a new alternative fuel to market, focusing on regulatory compliance and customer acceptance.
At this year’s Green Fleet Conference running from Oct. 29-30 in Schaumburg, Ill., Hicks will be part of a panel called "Looking Ahead: Emerging Alternative Fuels & Powertrains," where he will discuss DME as a sustainable, clean and efficient alternative to diesel.
Heavy Duty Trucking: What is DME and what are its benefits to the trucking industry?
Elliot Hicks: DME is a simple fuel. It’s made out of any source of methane, natural gas being the easiest to reform.
It gets the same power performance in a combustion engine that diesel does, so you aren’t losing any torque or efficiency by going with DME. The structure of the molecule doesn’t have a carbon-carbon bond, so it doesn’t generate any particulate matter when it burns. There is no need for a diesel particulate trap or a filter on the trap, making it much easier to manage for NOx control.
It’s a simple fuel to produce and transport because its handling properties are essentially identical to propane. It is stored at moderate pressure, liquefied at moderate pressure, and all the dispensing equipment is the same as propane except for a few modifications to seals and gaskets for material compatibility. There are very minor changes.
HDT: Do any modifications have to be made to a diesel engine to be able to run DME?
Hicks: The fuel delivery system has to be modified for DME because it handles like propane. You need to modify the tank, the pump and the injectors to handle the fuel flow, and the engine controller needs to be tuned for DME.
It’s very much the same as converting a smaller gasoline engine to run on propane, and on a diesel engine, once DME is actually injected into the cylinder, it will combust very efficiently.
With the DME engines that Volvo is commercializing, they are doing some additional modifications to cylinder geometry and optimizing other parts but you don’t need to have those in-cylinder modifications in order to run DME in a diesel engine.
HDT: What is the efficiency of DME compared to diesel gas?
Hicks: Volvo’s getting about the same thermal efficiency from the engine that they do from their diesel engines. On a volume basis, you need 1.88 gallons of DME to have the same energy content as one gallon of diesel. It’s very similar to LNG in terms of energy density.
You might need a larger volume of fuel, but in terms of getting actual work out of the truck, you'll see the same converted mileage and the same efficiency.
HDT: DME is interesting because it can be pulled from sustainable sources. What level of production could you actually see from those sources?
Hicks: Landfills and other biogas sources are certainly where we are focused. Initially there will be quite a bit of production from fossil natural gas in order to maintain a stable supply of DME as the market launches, but there is tremendous opportunity to extract it from waste gasses.
We see a lot of room for development of sustainable DME as the market develops. Whether the biogas is from food waste or other organic waste, those waste streams still have a lot of development be done but there are a lot of opportunities for turning those sources into DME.
HDT: How is your pilot program with Volvo and Martin Energy Services going and what have you discovered?
Hicks: It’s performing quite well. 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 cycles and set up of the truck.
Naturally with any switch-over 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.
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.
HDT: Are there other companies producing DME at a production rate or is this still the early days?
This is still relatively early days. We have our plant in Southern California that we actually run in a batch process because at the moment there are only 4 demo trucks out in North America. There will be some additional ones coming in the next year in advance of the commercial trucks being available. That will start rolling out in 2017 or 2018.That’s where the real volume of fuel will be needed, in order to support the commercial trucks.
HDT: Thank you for your time, is there anything else you'd like to say?
I'm looking forward to the Green Fleet Conference, it should be fun to be there
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