Boats Run Better on Isobutanol-Blended Gasoline and Renewable Biodiesel

All boaters can benefit from the Gevo biofuels, which include isobutanol, an oxygenate blendstock that can replace ethanol in gasoline, and renewable biodiesel, which can replace diesel from fossil-fuel sources, or be blended with it. Boaters understand the impact of greenhouse gases better than most people, because they see the effects fossil-fuel emissions have on the environment, as the resulting increased acidity harms fragile marine ecosystems.

Gevo makes isobutanol from inedible No. 2 corn, and it is considered an excellent replacement for ethanol as a gasoline oxygenate blendstock. Isobutanol, sometimes called “biobutanol,” has numerous advantages:

  • Isobutanol does not absorb water—a key feature for the open-vented fuel systems most boats use. There’s no phase separation with isobutanol.
  • It has a chemical makeup that is not corrosive on marine fuel lines and fuel-system components.
  • It will not damage fiberglass fuel tanks, nor will it cause galvanic corrosion in aluminum fuel tanks.
  • The National Marine Manufacturers Association has endorsed isobutanol as a fuel oxygenate blendstock.
  • Gevo takes carbon out of every step of its production process, so the carbon footprint is substantially lower than even other biofuels.

Gevo also makes low-carbon, renewable diesel, and it’s coming at the right time to meet increased demand since the Renewable Fuels Standard (RFS) and California’s Low Carbon Fuel Standard (LCFS) went into effect. The renewable diesel is expected to compete head-to-head on price with natural and petroleum-based equivalents, while reducing particulates and CO2 emissions. Also, the marine sector will have to reduce sulfur emissions to meet new international water regulations beginning in 2020. The proprietary, breakthrough process converts low-carbon isobutanol or low-value “fusel oils”—a mixture of alcohols that are byproducts from fermentation processes—into renewable diesel fuel.


Isobutanol Makes Boating Better

By Dr. Pat Gruber, CEO, Gevo, Inc.

Boaters are the kind of people who have a real knack for living in the moment. They show it by investing in their chosen fun, and by that I don’t mean money—boating is a great way to spend time with family and friends, get plenty of fresh air, and make the most of time off. Fueling up a boat can be expensive, but to boaters, it’s the price they have to pay to get that time on the water. These days many boats are finely tuned machines, so the right fuel is key to getting good performance. So much gasoline doesn’t meet the specifications engine manufacturers had in mind, a fill-up can cost more than just the price at the pump. The wrong fuel can be hard on boats and the resulting damage to the fuel system can result in downtime and lost days on the water.

If you love an activity like boating, you look forward to it, you think about it all the time, and it’s your escape. When the weather is good, it’s all you want to do, particularly in the northern areas where the season is short and sweet. Well, add unplanned boat problems, especially those due to something preventable like fuel issues, and suddenly your escape becomes a new source of stress and too many questions: When will the boat be fixed? Will we get out this weekend? Should we invite friends if we’re not sure the boat will run right?

Our isobutanol solves many fuel problems. It adds oxygen to every gallon, but just the right amount. Boats that sit idle won’t see any problems from gasoline blended with isobutanol: Once it’s blended it stays that way.

Boaters also manage to create some of their own issues because of the way they use their boats—sporadically. The fuel sits around in the tank, and not all gasoline blends react well to that. Because boats use what’s called an open-vented fuel system, and are generally kept in areas with higher-than-average humidity, water can get into the fuel system. It then phase-separates out of the fuel, dropping to the bottom of the fuel tank (where the fuel-pump pickup is located). It has to be removed with a fuel-water separator, or a boat needs to have an alarm fitted that alerts the operator of the water’s presence, to prevent damage to components.

All that being said, use of biofuel blendstocks came about as a response to the Renewable Fuel Standard (RFS), which came out of the Energy Policy Act of 2005, which states that a certain amount of transportation fuel in the U.S. needs to be from renewable sources—not fossil fuels. The Renewable Volume Obligations (RVO), or the amount of renewable fuel required by will grow to 36 billion gallons in 2022, that’s four times what it was in 2008. That’s good, the more the better.

Some blendstocks increase oxygen levels in the fuel, so burning that fuel is like adding oxygen to a fire: it will raise the temperature in the combustion chamber. While this doesn’t have much of an impact on a car engine, with its varying rpm levels throughout the day, boat engines can run at wide-open throttle for long periods of time, and that temperature can build up and damage engine components. Isobutanol, even when it’s blended at 16 percent of the fuel, only has 3.5 percent oxygen, very similar to the amount of oxygen in the common fuels today, such as a 10-percent ethanol blend, so the fuel burns at a temperature range where the engine was designed to run, all day long.

Another good thing about isobutanol: Since boating is often enjoyed in the summertime, when temperatures are hot, isobutanol actually lowers the volatility of gasoline. Volatility describes how quickly the gasoline evaporates, which causes hydrocarbon emissions from the fuel system. In some areas, fuel with higher volatility can cause engine vaporlock, where the fuel turns from liquid to gas within the fuel system, presenting engine problems on the water and taking up more of that valuable time. Stalling engines are not okay, and isobutanol helps boaters avoid that problem.

Isobutanol raises the octane of the base gasoline. Refiners can get a premium blend out of isobutanol quite easily, taking their base-stock gasoline with a lower octane level and blending in the isobutanol to get a higher octane in the final blend, delivering better performance, which commands a better price.

Boating Magazine did a decidedly unscientific hands-on test of a couple of Boston Whalers powered by Mercury outboards and reported its results, and the writer found the fuel showed a 17-foot center console with a 60-horsepower outboard had its fuel economy improved by 8 percent, while speed increased by 2.2 mph. A 24-foot center console with a 200-horsepower outboard saw a speed improvement of 1.4 mph and 6-percent-better fuel economy. Over a season that can add up to more boating.

So it’s no wonder the entire marine industry has embraced isobutanol-blended fuel, especially since Isobutanol is resistant to phase separation, and it doesn’t corrode fuel-system components, such as fuel tanks, primer bulbs, fuel hoses, gaskets, and O-rings. According to tests performed on engine oils by the U.S Department of Energy at Argonne National Laboratory (Emissions and Operability of Gasoline, Ethanol, and Butanol Blends in Recreational Marine Applications) the results suggest that isobutanol-blended fuel results in friction reduction but also a noticeable reduction in scuffing load compared to indolene, a non-oxygenated test fuel. Data collected during a multi-year test program suggests that isobutanol blends up to 16-percent volume can be used in recreational marine engines and boats without deterioration of performance, durability, or emissions characteristics.

The only problem with isobutanol? According to the Environmental Protection Agency (EPA), it’s too clean. Because biobutanol lowers the volatility of the fuel, it actually lowers the emissions too much for the EPA regulations, so in other words the fuel is too clean in some circumstances. Years ago, when the EPA wrote rules they didn’t know about IBA. Now, It’s just a matter of resolving some red tape. Once these regulatory hassles are altered, isobutanol will be blended by more refiners, and be available in more locations. Contact your government representatives about this issue. 

Look for an opportunity to try isobutanol in your boat, and you may find you never want to run another fuel, renewable or otherwise.