Recreational boats account for less than 0.1% of global greenhouse gas emissions, according to a report called “Pathways to Propulsion Decarbonization for the Recreational Marine Industry” commissioned by the International Council of Marine Industry Associations. The same vessels also create 0.7% of transportation carbon dioxide emissions in the United States and 0.4% of those emissions in Europe. By comparison, 46% of emissions are generated by powering homes and industry, and 14% of emissions are created by global transportation.

“It’s our purpose and role in life to inform the industry without any corporate bias,” says Joe Lynch, CEO of ICOMIA, which has worked with legislative bodies in the United States, Australia, Europe, the United Kingdom and Sweden to find ways to decarbonize the industry. “It’s driven by the fact that everybody knows sustainability is our key responsibility.”

The report, presented at Metstrade in November, followed several years of action by other bodies. In 2016, 196 countries signed the United Nations Paris Agreement with the goal of achieving the “tolerable” limit of 1.5 degrees centigrade above preindustrial levels. To achieve that, greenhouse gases must peak before 2025 and decline by 43% by 2030. “Current forecasts are that we are not on track to meet this,” according to ICOMIA’s presentation.

In the past two decades, the U.S. recreational boating industry has decreased marine engine emissions by more than 90% and increased fuel efficiency by more than 40%, according to ICOMIA.

Two years ago, ICOMIA and its technical committee tapped the independent, U.K. firm Ricardo to research emissions and the marine industry’s carbon footprint for a realistic look at how to best remove emissions from recreational boating. The organization chose Ricardo because the firm “has a long track record of [life cycle assessment] studies and is familiar with the fuels for the marine environment,” Lynch says. “They had no bias or agenda.”

He adds that the report was named “pathways” because the decarbonization process is going to take many routes and years, and needs the support of industry, government and the consumer. “The driving force was to get the baseline data to create informed debate,” Lynch says. “Nobody wants to make decisions based on a hunch or emotions. There is no one-size-fits-all solution to reduce the carbon emissions of propulsion.”

One area that virtually everyone agrees needs improvement for decarbonization to succeed is the industry’s infrastructure. “We will use the research to start the discussions to lobby for infrastructure investment,” Lynch says. “This is the start of the first phase, sharing the results as widely as possible and continuing to work with regulators and legislators.”

The next phase will be to discover where any gaps might exist in the research. For example, Ricardo didn’t look at foiling, but it’s something that will garner more attention as the technology evolves.

The release of the report is the first part of a multiyear plan that will start with educating the industry, followed by educating legislators and regulators and, eventually, consumers. “Our education agenda will be to the industry initially and to the legislators to develop sensible guidelines,” Lynch says. “It’s about moving to a consumer-focused campaign, and finding and identifying more partners to work with to expound and extend the body of work.”

All Charged Up

With such companies as Candela and Vision Marine Technologies setting endurance and speed records with electric boats, the marine industry and the public have often assumed that boating would follow automobiles by using electrification to reduce carbon emissions. “The thing I worry about is the ‘we are going to electrify the entire industry’ statements,” says Jeff Wasil, senior director of environmental health and safety compliance for the National Marine Manufacturers Association. “As far as I’m concerned, there’s a tremendous focus on the whole electrification bit.”

The problem with the focus on electrification is the difference in usage and life cycle between cars and boats. A typical car is sold after a relatively short time and hundreds of thousands of miles, while many boats have a lifespan exceeding 30 years because they’re typically used less than 50 hours a year. “You’re trying to compare a life-cycle assessment of 150,000 miles compared to 38 or 40 hours a year,” Wasil says.

In the report, Ricardo found that 50% of a small boat’s carbon impact comes during the manufacturing process, 40% takes place during operation, and 10% comes at the vessel’s end of life. Conversely, 85% of a car’s carbon impact results during operation, 10% takes place during manufacture, and 5% comes at the vehicle’s end of life. “What’s fundamentally different between boats and cars is the carbon that goes into the build phase and the use phase,” Wasil says.

Adding complexity to a boat reduces production volume and can generate more carbon emissions during construction. The industry knows how much carbon goes into installing a conventional internal combustion engine and fuel tank in a boat. “If you put in hydrogen or electric propulsion, you’re front-loading 30 or 40 years of carbon life into the boat,” Wasil says. “The carbon footprint of building those thousands of [traditionally powered] boats is going to be much less than the building of those eight [electric or hydrogen-powered] boats.”

The report concluded that a battery-powered electric propulsion system has “a notably higher contribution from raw materials and manufacturing than other propulsion systems.” Consequently, vessels with “green power” that get less use won’t see big sustainability gains compared with traditionally powered vessels. In addition, according to the report: “It is important to note that this study considers battery lifetime in years rather than recharging cycles, as battery performance is expected to degrade over time due to calendar aging despite low utilization. This could further impact a craft with a long lifetime but little utilization, as it will be assumed to require numerous battery replacements throughout the craft’s lifetime.”

Ricardo also found that the amount of downtime boats experience “makes it more difficult to achieve sufficient emissions reductions in the use phase to outweigh the higher production and maintenance impacts of electric-only, hybrid and hydrogen systems. These embodied impacts are especially associated with the battery and hydrogen storage components, and are magnified if these components must be replaced in the lifetime of the craft.”

Boatbuilders and engine manufacturers aren’t getting enough credit for reducing carbon during the manufacturing process, Wasil says. When he worked at BRP, the company used the energy generated during engine testing to power the facility, saving money on utilities.

Still, Wasil says, there is a place for electrification in applications such as foiling surfboards, small boats powered by portable electric outboards, and the like. “There’s a lot of good cases why you’d want to go with an electric outboard,” he says.

The Big Picture

Because people own boats longer than cars, Wasil says, the quickest path to decarbonization is dealing with the existing fleet of 12 million recreational boats worldwide. Sustainable fuels such as biobutanol and hydrotreated vegetable oil are drop-in replacements for conventional gasoline and diesel, and require no engine modifications. In its life-cycle assessment conclusions, the Ricardo report said e-gasoline internal combustion engines offer the greatest potential to reduce greenhouse-gas emissions of privately owned gasoline craft, “but only if low-carbon electricity is used in fuel production.”

For diesel engines, the report stated that renewable diesel fuel, specifically HVO internal combustion engines, “can provide the largest global warming potential reductions for diesel craft provided the fuel is produced using waste feedstocks.”

Ricardo did life-cycle assessments of nine types of boats with five varieties of propulsion systems, with conventional gasoline and diesel, HVO, alternative fuel and electrical power. The research looked at decarbonization options, a greenhouse gas life-cycle assessment, total cost of ownership, power-systems implications and infrastructure implications.

The report showed that a displacement powerboat is used annually for an average of 48 hours and has a lifespan of 45 years. For this type of boat, Ricardo determined that switching to a drop-in sustainable marine fuel would have the biggest impact, resulting in a 40% reduction in emissions. “Electric propulsion would present too great of a range compromise,” the report stated.

For a sailboat, the annual usage averages 24 hours and the lifespan is 45 years. In this case, the data showed that a sustainable marine fuel would have the biggest impact, creating a 30% reduction in emissions. “The long life and low annual engine hours make it impossible to offset the manufacturing impact of other technologies,” the report stated.

A high-performance motoryacht less than 65 feet gets used for 130 hours a year and has a 50-year lifespan, according to the report. The results showed that “all alternative technologies could present an opportunity” and that “hydrogen presents an interesting opportunity given the high utilization.” Ultimately, though, “sustainable marine fuel presents the biggest carbon reduction.”

Personal watercraft used in a high-hour rental operation get used an average of 156 hours per year and have a shorter lifespan of 12.5 years because of that higher usage. “Assuming that range reduction is not a limitation,” the report stated, “an electric propulsion system produces the highest carbon reduction.”

Useful Data

Conclusions drawn for total cost of ownership stated that sustainable drop-in fuel internal combustion engines and parallel hybrid power systems are “the most suitable decarbonization options for privately owned recreational craft.” Boats used in rental applications could be more suited to adopt hybrid or battery electric propulsion.

For marinas that want to decarbonize, the report stated, hydrogen and sustainable-fuel refueling infrastructure would provide better total cost of ownership than electric charging stations because of higher refueling speeds.

The total cost of ownership, including purchase price and operation, would increase with all propulsion technologies. By 2035, the report stated, battery-powered electric systems would yield cost increases of 40% to 250%, and hydrogen system prices would go up 85% to 200%. Hybrid systems would go up 25% to 115%, while sustainable drop-in marine fuels are projected to rise 5% to 45%. “These costs should be reduced over time as alternatives achieve market scale,” the report stated.

Regarding infrastructure and making alternative fuels more readily available, LyondellBasell, which operates some of the largest refineries in the world, is making a gasoline replacement called Ideal EMP at its refinery in Houston. Ideal EMP is a non-alcohol, high-octane gasoline blend that’s registered with the federal Environmental Protection Agency. It’s made with 42% renewable content. It will be distributed by VP Racing Fuels, and there’s an effort underway to improve the overall infrastructure to get replacement fuels to marinas. It’s available in 12 states, including popular boating areas such as Florida, Alabama, Georgia and Texas.

On its website, LyondellBasell says Ideal EMP is “ideal for recreational marine and off-road applications that cannot use E10 gasoline due to its corrosivity and potential to phase-separate.” The company adds that EMP-based gasolines can reduce greenhouse-gas emissions up to 30% more than E10 at the same renewable content. It also reduces other exhaust and evaporative emissions from gasoline. Ideal EMP can reportedly also improve combustion, power and gas mileage.

“With any of these alternatives, they work really well in the engines and reduce carbon dioxide, but the biggest challenge is getting them to the marinas,” Wasil says. “When you’re trying to get 2,500 gallons to Bob’s Marina and Bait Shop, that’s where we need support from policy makers to help with that.”

Wasil says the development of e-fuels should continue to advance, and they likely will play a greater role as prices come down. Another example is a Chilean company that’s using wind and solar power to make synthetic gasoline by pulling carbon dioxide out of the atmosphere. “Once they get the electricity, it’s easy to make the liquid fuels,” Wasil says. “As recently as five years ago, when you talked about e-fuels, they were pie-in-the-sky technology, but now they’re getting down to only $10 a gallon. Do not discount the role that e-fuels will play in our ability to reduce emissions moving forward.”

Higher Education

Wasil says education will be the key to making decarbonization a reality. “Especially policymakers and legislators,” he says. “They’re not educated enough on the ins and outs of the challenges of the recreational boating industry.”

Next up will be educating the consumer because all the alternative fuels and propulsion systems won’t mean a thing if someone won’t buy them. “That’s the quandary we’re in,” Wasil says. “I want to be quoted in terms of taking the most pragmatic approach to reducing carbon emissions. We have to do our part and make it affordable and convenient for consumers to do their part.” 

This article was originally published in the January 2024 issue.