As biodiesel finds its way into commercial marine applications, the green alternative to conventional petroleum-based diesel is fueling debate and raising questions.
Biodiesel is a clean-burning fuel produced from feed crops such as corn and soybean or from waste vegetable oil through a refinery process called transesterification. Alone, it contains no petroleum products, but can be easily blended with petroleum diesel at any level, or used alone.
For marine applications, biodiesel offers some advantages: it is biodegradable, non-toxic and essentially free of sulfur and aromatics.
According to the National Biodiesel Board, the fuel is environmentally friendly. It is harmless to fish and is easier on vessel crews in terms of exhaust odor, which has a tendency to irritate eyes.
"It's a cleaner burning fuel and only slightly more expensive" than petroleum-based diesel, said Andrew Cole, owner of Portsmouth Harbor Cruises in Portsmouth, N.H.
Cole is captain of Heritage, a 60-passenger tour boat built in 1963. He runs a 5 percent biofuel mix in Heritage without any modification and feels that its high lubricity is an advantage, especially in older engines.
Biodiesel has an advantage when it comes to preventing engine wear, said Scott Dubrow, sales manager for the Mack Boring Co. in Union, N.J., a supplier of marine diesel engines and parts. However, biodiesel's viscosity can be a problem in cold weather, Dubrow said.
When mixed, it is less expensive than straight diesel, but Dubrow said operators must adhere to engine manufacturers' guidelines for using biodiesel or risk invalidating their warranties. Because of chemicals used in the refining process, biodiesel can have deteriorating effects on rubber hoses, gaskets and other components.
|The Portsmouth, N.H-based tour boat Heritage runs on a 5 percent biofuel mix. The operator, Portsmouth Harbor cruises, says green fuel has lubricating properties.|
Availability, fuel stability and varying quality are concerns when using biodiesel. Oliver Baer, president of Clean Emission Fluids Inc. in Grosse Pointe, Mich., said the quality of biodiesel can vary greatly, from "garage biodiesel" made from a variety of vegetable waste oils to carefully engineered corn and soy biodiesel that has been properly manufactured and stored. When compared to petroleum diesel, which has an unlimited shelf life, biodiesel lasts only about six months under ideal conditions.
Availability becomes a problem because the fuel is produced in relatively small batches, and distributors are hesitant to convert existing tanks or install new ones to accommodate the variety of biodiesel mixes.
In an effort to solve the problems of storage and availability, Baer's company manufactures and installs on-demand blending and storage equipment systems. It tests fuels aboard its tug Titan on the Detroit River.
Ron Ackman, owner of Oldport Marine in Newport, R.I., said his launch and tour-boat company began using biodiesel about 10 years ago. Oldport is a Yanmar dealer.
"At that time we were running 100 percent biodiesel in our boats, fuel which we received with the help of a state grant. We also made sure that Yanmar was OK with it. From 2007 to 2008 we ran B20 (20 percent biodiesel, 80 percent petroleum diesel). We ran it without any problems,'' Ackman said. He noted, however, that biodiesel tends to gel and make cold starts difficult.
Today, Ackman no longer uses biodiesel, in part because it is not readily available on his waterfront. He is also concerned about the conversion of food-producing acreage to biofuel farms. Ackman feels that a lot of the hype behind biofuels come from politics and the 'feel good' factor. He has mixed emotions about the fuel and about ethanol, a vegetable-based product that he believes was promoted largely "to say that we are making a homegrown fuel instead of relying on foreign oil."
The future of biodiesel appears to lie with the U.S. Environmental Protection Agency (EPA). The EPA's recently proposed rule requires renewable fuels to meet certain greenhouse gas emission reduction targets. The EPA believes biodiesel does not.