Ethanol: are diesel owners next?

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Implementing an ethanol-diesel program would be more complex than it was with gas, but you never know

Implementing an ethanol-diesel program would be more complex than it was with gas, but you never know

The introduction of ethanol into the gasoline supply chain has certainly caused problems — some of them seriously expensive — for boat owners. After some false assumptions and journalistic detours were corrected, the problems, their causes and effects have been fairly well documented. But other than the fact that some fiberglass gasoline tanks will have to be replaced, the final solutions to the rest of the ethanol-

related issues are still being worked out.

While all this was going on, owners of diesel-powered boats could be forgiven for the occasional smug smile they displayed while congratulating themselves for being free of such worries. But have they truly escaped, or has their day of reckoning just been delayed? Diesel-powered vehicles of all types consume more than 36 billion gallons of fuel each year in the United States, so diesel presents an inviting target for any scheme that promises to reduce both emissions and our dependence on imported oil.

Biodiesel has received a lot of coverage in the press and especially on television, where the aroma of hot french fries emanating from the exhaust of a passing bus is a big story. The properties of biodiesel are such that it can be burned effectively in most diesel engines without significant modification. However, restricted supplies and a lack of processing systems will probably limit its annual use to its present level of 15 million gallons or so, a mere drop in the bucket compared to current diesel fuel consumption. Another alternative with the potential for much wider use (on paper anyway) is e-diesel, a blend of ethanol and diesel fuel.

First, some background. Diesel-ethanol blends are a reality, not just fiction, and they reportedly suffer from most of the drawbacks that plague gasoline-ethanol blends: the tendency to separate at low temperatures and in the presence of water contamination, damaging effects on some materials, the growth of bacteria, and difficulty in transporting the product to market. Much of the research on e-diesel was sponsored by the Department of Energy under its Biomass Program. It focused on diesel fuel with concentrations of up to 15 percent ethanol and up to 5 percent special additives to prevent the ethanol from separating out of the fuel. Tellingly, the DOE reportedly now has “refocused its research and development” and e-diesel is “no longer a research priority,” according to information from the Biomass Program Web site (

Some of the reasons for this “refocusing” could be contained in a report published by another government agency, the National Renewable Energy Laboratory ( ). “Safety and Performance Assessment of Ethanol/Diesel Blends (E-Diesel)” is a 48-page tome that is weighted down with copious charts, facts and figures, but thankfully presents its conclusions briefly, mainly addressing the safety and performance aspects of the blended fuel.

On safety, it states that the increased flammability and volatility of e-diesel prevents it from being blended, transported, stored or delivered via the infrastructure now used for heating oils and diesel fuels. This would require a massive and expensive changeover to infrastructure and on-vehicle systems similar to those used for gasoline to reduce the risk of fire or explosion. At a minimum, this would require land-based storage tanks, pipelines, trucks and delivery points to be equipped with flame-arresting vents, effective vapor-recovery systems, and positive grounding between the fuel dispenser and the receptacle being filled. Boats would have to be modified with sealed fuel systems, bilge blowers and in-tank fuel level sensors that were appropriate for the extra volatility of ethanol. Electrical devices below deck that weren’t specifically designed for use in a volatile atmosphere would have to be replaced.

On the performance issues associated with e-diesel, the report recognizes a reduction in engine power output due mainly to three causes: cavitation caused by vapor lock in fuel pumps or vaporization in injectors, fuel filter clogging, and ethanol’s lower power content and the presence of blending agents that may contribute little or nothing to the combustion process.

The report suggests that all safety and performance issues could be addressed by upgrading infrastructure as outlined above and modifying vehicle systems, adding additional fuel pumping power, restricting fuel return lines, and modifying injector pumps (or microprocessor controls) to increase fuel delivery rates. The report’s logical conclusion is that the massive changes and resulting expense required to support the widespread use of e-diesel are “unacceptable” and “likely unwarranted.” The cost far outweighs the benefits (if any).

The other important drawback in the potential use of e-diesel is ethanol’s lack of lubricating properties, leading to a dilution of the natural lubricity of diesel fuel. This would require the addition of still more additives to protect engine parts — such as fuel pumps, injection pumps and injectors — that derive some of their lubrication from the incoming fuel. And as it stands, e-diesel wouldn’t meet the ASTM standard for diesel fuel and, therefore, couldn’t be widely sold.

Fortunately, the cards seem stacked against any attempt to institute an e-diesel program on the scale of what we see happening in the gasoline industry. Technical and cost issues aside, the shortage of ethanol that will result from the congressionally mandated gasoline program should help keep the idea in limbo for a long while. And the sheer cost and complexity of instituting an e-diesel program should deter the Feds indefinitely.

Ethanol in gasoline was comparatively easy to implement on a gradual basis. There were no additional safety considerations. Cars didn’t have to be modified to use it. Delivery methods had to change slightly, but there was no disruption to speak of. Sure a few boat owners were inconvenienced, but the average consumer was blissfully unaware of the change.

A switch to e-diesel will be far more difficult, expensive and fraught with potential danger. Its presence in a system that isn’t equipped to handle it can result in fire and explosion. Its use in an engine that hasn’t been modified for it will result in reduced performance and greater overall fuel consumption, a reduction in reliability, and the potential for accelerated wear or outright damage. Taken together, the many drawbacks, hurdles and expenses involved in implementing e-diesel should cause any reasonable person or agency to agree with NREL, whose conclusion might be paraphrased as, “it’s just not worth it.”

As the owner of a diesel-powered boat, I’m smugly comfortable that I won’t have to deal with e-diesel anytime soon. But then I remember that the final e-diesel decision could result from the pet project of a politician from Nebraska whose last six campaigns were financed by agro-business. And I shudder. This would be a good time for sanity to reign.

David Yetman is a freelance writer and regular contributor to Soundings.