Alcohol & Boat Engines
Is There Another Way?By Ryck Lydecker
Published: December 2011
Federal law says the nation must increase its "biofuel" capacity dramatically in the next decade, but does it have to be ethanol?
"The National Renewable Energy lab sanctioned a series of performance and durability tests on both two- and four-stoke outboards (see sidebar) and we know that E15 can seriously damage those engines," Mc Knight added. "Right now in the U.S. we use 14 billion gallons of corn-based ethanol in gasoline, but the nation is under a federal mandate to increase biofuel consumption to 36 billion gallons by 2022. So we thought it was time to look for an alternative to ethanol, and after analyzing our tests of last summer, we may have found just that in isobutanol."
Although discovery of isobutanol as a byproduct of plant fermentation goes back to 1861, it's only due to innovations in biology over the past 20 years that it's become a viable and potentially cost-effective fuel source, according to chemical engineer Dave Munz. As a member of the team that conducted the June boat trials, Munz and his company, Gevo, a Colorado-based isobutanol producer, supplied the fuel. Isobutanol, Munz said, is everything ethanol isn't; it's non-hygroscopic, meaning it absorbs little water, and its use would avoid the fuel phase-separation problems in boat engines that aren't run regularly. In addition, isobutanol is not as potent a solvent as ethanol, so it might be the panacea for older boats with fiberglass fuel tanks.
From a distribution-cost perspective, Munz explains that because isobutanol is less corrosive than ethanol, it can be shipped by pipeline as opposed to the more expensive truck and rail transportation that ethanol demands. "We think it can solve a lot of problems for the fuel industry, as well as for the consumer," he adds.
The EPA has ruled that isobutanol, even at a higher percentage, is a "substantially similar" fuel, meaning that small retailers like rural convenience stores and marinas should not have to retrofit or replace their gas pumps, which can help keep prices down. That "higher percentage" is one of isobutanol's chief advantages: It's got 30 percent more energy than ethanol.
Fuel Of The Future?
Gevo, in fact, supplied isobutanol fuel for an entire summer of testing, according to John Adey, technical director for the American Boat and Yacht Council and a member of our BoatUS Magazine tech team writing "Ask The Experts." Adey handled logistics for the four-month project and designed test protocols that put three boats through their paces on isobutanol.
"By the time we were done in September, we'd gone through about 800 gallons of isobutanol-enhanced fuel," Adey reported. "We wanted to conduct the scientific emissions tests, but also just to operate the boats on this fuel the same way regular boaters would during a summer." Adey's work actually started in March, prepping the boats: a Mako 19 with a 175-hp Evinrude E-Tec, two-stroke outboard; an 18-foot Sea Ray with 135-hp Mercruiser inboard/outboard power; and a 23-foot Sea Doo with twin 215-hp Rotax engines driving its jet pump. In addition to the calibrated and controlled emissions testing in June, Adey, McKnight, and others (including a few BoatUS staff who were asked to help) logged 40 hours, what EPA determines the average "seasonal life" for recreational boat engines, on each boat.
The June emissions testing with the Mako provided a baseline for the entire summer suite of evaluations. According to Jeff Wasil, engineering technical expert for Evinrude Marine Engines, and inventor of the MPSS, which stands for Marine Portable Sampling System, the first "bag run" captured exhaust with the engine burning a pure, EPA-approved, test gasoline called Indolene.
"Two years ago we investigated how isobutanol would work in one of our outboards and its properties seemed much better suited for marine engines," Wasil said. "We found no appreciable changes in emissions and because you get more energy without more pollution, and with a fuel that appears to be more compatible with marine engines, isobutanol looks more promising than ever as a replacement for ethanol."
Coming To A Pump Near You?
Wasil notes that the U.S. Department of Energy has designated isobutanol a "drop-in fuel," meaning that it can be used to displace petroleum under the Energy Independence and Security Act of 2007, and increasing its use could help reduce greenhouse-gas emissions faster as well. It can be produced from agricultural waste products like corn stalks, or from switch grass and wood chips. At last count at least 10 companies worldwide, including a BP-Dupont joint venture called Butamax were working toward commercializing isobutanol in the next few years, according to chemical-industry reports.
"There is no need to rush E15 into the marketplace," Wasil told the House Subcommittee on Energy and Environment in testimony for NMMA last July 7. He appeared before the panel to address the risks of the EPA's "partial wavier" allowing 15-percent ethanol fuel, or E15, to be used in some engines and not others. He told lawmakers, "Let's have a strategic pause while more testing is done to determine the effects of E15 on various kinds of engines and to see whether there might be alternatives to ethanol, such as isobutanol."
With the baseline emissions tests quite literally in the bag and a full summer of routine operation logged on all three boats, at press time Team Isobutanol planned to conduct the emissions test sequence again and look for anomalies. "We want to find out if, after 40 hours of running time, the engines still comply, or if there were any ill-effects," Adey explained in late summer. "So far, the engines are running better than ever. Power is excellent and fuel economy seems improved; in fact, I'm amazed at how great this fuel seems to be."
But if one of the engines doesn't pass the next "bag test," scheduled for the fall, after boating season, Adey said technicians would tear it down and determine how any failures may relate to the fuel. As Wasil put it, "It's important for the marine industry to secure a fuel that we know is going to work in our products and that consumers can depend upon." McKnight said a full report on the project would be ready for presentation at the Miami International Boat Show
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