A five-year test program found that biobutanol would be a much better choice for gasoline blends compared to ethanol. The marine industry continues improvements to energy efficiency and addresses the Renewable Fuel Standard, while raising concerns about the damaging effects of higher concentrations of ethanol on marine engines. From a National Marine Manufacturers Association (NMMA) press release:

Engine manufacturers from across the recreational boating industry have identified biobutanol as a suitable and safe alternative biofuel to ethanol, a controversial biofuel due to its damaging effects on numerous types of engines, including those that power recreational boats. For the past five years, the National Marine Manufacturers Association (NMMA) and the American Boat and Yacht Council (ABYC) under the direction and guidance of the U.S. Department of Energy and Argonne National Laboratory, have been engaged in an industry-supported program to evaluate the performance of recreational marine engines operated on fuel containing up to 16 percent biobutanol.

The research and subsequent resolution to formally move forward with butanol as an industry-wide biofuel alternative comes as the industry focuses on addressing the congressionally-mandated Renewable Fuel Standard (RFS) requiring 36 billion gallons of renewable fuel to be blended into the gasoline supply by 2022.

The recreational boating industry is highly focused on the need to move towards alternative, renewable fuels and continues to support that effort. However, it is important to find fuel sources that are not only renewable but also safe for all engines and consumers who may use them. Methods to increase renewable fuels in the gasoline supply have primarily focused on ethanol, specifically fuel with a higher blend of ethanol such as E15 (fuel with 15% ethanol). Multiple reports show that ethanol blends greater than 10 percent cause significant damage to marine engines. As a result, the marine industry has explored biobutanol fuel blends with very promising results. Most notably, biobutanol does not phase separate in the presence of water like ethanol. Phase separation occurs when water is introduced and ethanol separates from gasoline, forming two separate solutions. An engine won't run on the ethanol solution, which sinks to the bottom of the tank and is highly corrosive. Additional encouraging properties of biobutanol are its higher energy content compared to ethanol and the fact that it has caused no performance-related issues in marine engines.

While large scale consumer availability of biobutanol fuel blends is not expected for another couple of years, the boating industry’s supportive position is poised to encourage its market expansion by providing marine fuel distributors, retailers and consumers with the confidence that this is not only a suitable, but a more compatible fuel for boats.

John McKnight, senior vice president for government relations at NMMA says, “The recreational boating industry is proud to be on the leading edge of renewable fuel research as we continue to work towards a solution for our industry and the many others that are impacted by the RFS. Our on-water and laboratory testing of biobutanol has been conducted in a wide variety of recreational marine engines and boats, giving us confidence that this fuel is a safe, viable alternative to ethanol.”
“We are very excited that NMMA has shown industry leadership in support of renewable isobutanol," said Gevo CEO Patrick Gruber. "Gevo has been an active partner with NMMA for the past 5 years, and has supplied all the renewable isobutanol and blended fuel used for on-water testing.”

“I'm thrilled that the entire recreational marine industry could come together to agree on a biofuel that indicates so much promise for our industry,” said Jeff Wasil, Engineering Manager for Emissions Testing, Certification & Regulatory Development at Evinrude. “Not only has the industry signed off on the resolution, but it has been very supportive of the efforts over the past several years -- stepping up with boats, engines, and people to collaborate in the testing. We've looked at the situation and offered a real solution for the industry and consumers.”

Paul Beckwith, CEO at Butamax™ Advanced Biofuels said “Butamax welcomes NMMA’s findings on the compatibility of fuel blends of up to 16 percent biobutanol with marine engines. We believe that these results from the extensive evaluation performed by NMMA and its partners are a powerful addition to the large body of work on biobutanol compatibility with automotive engines and fueling infrastructure which Butamax has sponsored and published. Butamax’s work to secure the EPA and UL approvals necessary to make 16 percent biobutanol blends broadly available for use in on-road engines and existing refueling infrastructure continues.”

John Adey, ABYC president stated “Participating in this testing from an engineering standpoint ensures that the boating public will enjoy reliable fuels that work well with new and existing product with little to no noticeable changes in the way boats are built and used.”

The recreational boating industry’s biobutanol research is supported by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, coordinated through Argonne National Laboratory. The testing results have been fully documented in published peer reviewed studies. Those participating in the testing from the recreational boating industry include engine manufacturers Volvo-Penta, Evinrude, Yamaha, Mercury Marine, Honda, Tohatsu and Indmar as well as the National Marine Manufacturers Association (NMMA), the American Boat and Yacht Council (ABYC) and the United States Coast Guard (USCG).

For more information on biobutanol, visit the U.S. Department of Energy Alternative Fuels Data Center.