The Pathways to Propulsion Decarbonisation for the Recreational Marine Industry, sponsored by the International Council of Marine Industry Associations( ICOMIA), was released in 2023. Has it yielded any forward movement?

It’ s been two years since the International Council of Marine Industry Associations( ICOMIA) published the landmark Pathways to Propulsion Decarbonisation for the

By Sarah Devlin & Tim Murphy, ABYC

Recreational Marine Industry. ICOMIA had commissioned Ricardo PLC, a third-party consultant, to work with more than 100 marine groups around the world to investigate propulsion technologies for recreational vessels under 24 meters( approximately 80 feet) in length, including battery electric, hybrid electric, hydrogen, and internal combustion.

The Pathways report looks at the impact of lifetime greenhouse gas( GHG) emissions, financial cost, usability, range, performance and infrastructure implications, and provides recommendations for decarbonization.“ It’ s the most comprehensive lifecycle assessment of recreational watercraft ever conducted,” said Darren Vaux, ICOMIA’ s then-president.

“ One of the challenges the marine industry faces, honestly, is perception ― the perception that recreational boating contributes unnecessarily to global climate change,” said Jeff Wasil, vice-president of environmental compliance and marine technology at the National Marine Manufacturers Association( NMMA). He made this statement during a panel discussion titled“ The Carbon Conundrum” at the International BoatBuilders’ Exhibition and Conference( IBEX) in 2023.

In reality, while the U. S. transportation sector accounts for 29 % of the GHG emissions emitted into the atmosphere, recreational boating accounts for 0.7 %.

“ The fact that recreational boating is really small doesn’ t give us an excuse to stop worrying about this,” Wasil continued.“ Everyone needs to do their part to minimize CO2 emissions.”

For any given boat, its carbon footprint includes how much GHG is embedded in the product, as well as how much is emitted during operation. At first glance, an all-electric boat may seem like the greenest choice for reducing our carbon emissions on the water. But, how green a boat is depends on how frequently it is used set against the cost of building and disposing of it.

Analyzing the lifecycle of an electric boat takes into account mining and energy costs related to producing lithium-ion batteries. If the boat’ s usage is anywhere near the national average, a disappointing 37 hours per year according to the Pathways report, it may be far costlier than the usage costs of carbon emissions associated with traditional internalcombustion engine( ICE) propulsion. One directive or recommendation does not fit all boats.

The report pointed out other crucial drawbacks in regard to electric boats.“ Pure battery electric-propulsion craft will require a significant reduction in range and potentially also power to mitigate impacts on vessel mass, onboard volume, and purchase price,” the report said.“ It is impractical to match the range and performance system, as batteries take up too much space within the craft or are too heavy to be practical.”

The lifecycle assessment for pure electric boats found that“ craft types with lower utilization are unlikely to find that the battery-electric system results in reduction of GHG compared to the baseline ICE.”

Hybrid systems and sustainable-fuel ICEs rated well as they“ can maintain the same range and power as current baseline ICEs with minimal to no impact to the vessel displacement and onboard space,” according to one of the report’ s summary statements.

The Pathways report sees the greatest promise with sustainable drop-in fuels.“ If the production of drop-in fuels and hydrogen is optimized( i. e., biofuels from wasted feedstocks and hydrogen produced via electrolysis with zero fossil-fuel electricity), then the propulsion systems powered by these fuels represent the greatest potential to reduce GHG emissions under the study’ s assumptions.”

TOTAL U. S. GREENHOUSE GAS EMISSIONS BY ECONOMIC SECTOR

Transportation 29 %

Residential & Commercial 13 %

Agriculture 10 %

Industry 23 %

Electric Power 25 %

Source: United States Environmental Protection Agency( EPA)

18 July / august 2025 www. boatingindustry. com