Why electric motors aren’t yet the greenest outboard option

It’s hard to miss the proliferation of electric outboard motors at boat shows over the past few years, as tightening environmental regulations aim to guide us all toward a greener, more sustainable future. Proponents of electric outboards point to their quiet operation, and to their lack of greenhouse gas (GHG) emissions as being better for the environment. Critics, on the other hand, argue electric motors offer limited run times at anything above idle speed, while their lithium battery packs simply trade one environmental problem for another.

With the discussion weaving back and forth and relying more on rhetoric than hard data, it’s been difficult to know what to believe. That all changed this past November, however, with new research presented at Metstrade, the world’s largest boating industry trade show. It suggests internal combustion engines aren’t the villains they’ve been made out to be, and could, in fact, represent the cleanest option for anglers and hunters looking to minimize their carbon footprint.

REVEALING RESEARCH

Published by the International Council of Marine Industry Associations (ICOMIA), the Propelling Our Future research study compared the cradle-to-grave environmental impacts of five different propulsion technologies to determine which is the cleanest. Those included internal combustion engines burning gas or diesel, internal combustion engines burning sustainable biofuels such as hydrogenated vegetable oil (HVO), battery-powered electric motors, hybrids, and engines burning pure hydrogen.

The study generated 45 full data sets by examining each of the five propulsion technologies in nine different types of watercraft—aluminum fishing boats, pontoon boats, bowriders, rigid inflatables, personal watercraft, cruisers, sailboats, motor yachts and commercial barges. It represents by far the most detailed research yet into the true environmental impacts of different propulsion systems used in boats.

And what was the cleanest technology, according to the study? Internal combustion engines burning sustainable fuels such as HVO came out on top—and by a convincing margin—in every single category except personal watercraft, where battery-powered electric motors won by a nose.

In the case of a typical aluminum fishing boat or pontoon, the ICOMIA study revealed a standard outboard engine burning sustainable fuel instead of gasoline immediately chops GHG emissions by 60 per cent. While it concedes battery-powered systems provide a 100 per cent reduction in GHG, the study notes they leave behind a greater environmental impact when measured over their full life. That’s due to the hefty environmental cost of manufacturing lithium batteries, then disposing of them at the end of their lifetime, which more than offsets the initial GHG advantage.

COMBUSTION QUESTION

So, what about this HVO stuff? Aren’t we just trading one form of oil for another? Not at all, says ICOMIA. Unlike fossil fuels, vegetable oil is a renewable resource, with no need to drill beneath the sea or frack under people’s drinking water. What’s more, we can start by simply repurposing the billions of litres of HVO that already go straight into landfills each year after spending a few days in a deep fryer. The stuff may no longer cut it for preparing food, but it’s still perfectly fine to power an engine.

Best of all, most existing gas and diesel engines can burn HVO as is, or with only minor mechanical modifications. A pilot project currently underway in Florida, for example, has so far collected more than six months’ worth of data showing no negative impacts on test outboards after switching to exclusively burning HVO.

Cynics might say ICOMIA has a vested interested in pushing internal combustion engines since it is, after all, a trade association for the boating industry. But ICOMIA represents companies that make battery-powered motors, as well as those that build gas outboards. The organization simply wants to help sell more boats, regardless of how they’re powered.

What ICOMIA’s research makes clear is there’s no free lunch, and that even seemingly inert battery systems still have an environmental impact. It also shows we don’t have to continue burning gas while we wait for improved batteries with greater run times to be developed. Instead, we have the opportunity right now to slice carbon emissions by up to 60 per cent by switching to a fuel source we’re already dumping into landfills.

Surely, that merits a closer look.