Myth vs. Reality: Electric and Hybrid Marine Propulsion
Published: Friday, April 3, 2020
By: Zuzana Prochazka
Electric and hybrid propulsion systems for boats have been on the horizon for years but how close is a real and affordable mass-market solution? The green movement gets a lot of attention but it’s the need for energy independence that’s driving the need for alternate propulsion. So far, the market has been developing in fits and starts so let’s see what is myth and what is reality today.
Market Overview
The marine industry is a niche market. It’s small and slow to adapt, and it has dozens of segments that behave differently. The growth of electric and hybrid cars has helped electric boats get some traction but the two aren’t as close as you’d think and the numbers on both are still low. Less than two percent of passenger cars worldwide are now electric while only 1.3% of boats are integrating e-propulsion.
Additionally, boats are more complex than cars, with onboard systems expected to provide electricity for extended living; the hotel needs on an autonomous distance cruiser are far different from those in automobiles. Boats have a different frequency and variance of use than cars, and many segments—like ferries, sailboats, and small high-speed planers, for example, where boats are used differently. These differences are making it hard to build one solution that fits all.
Why E-Propulsion?
There are numerous benefits to e-propulsion including that it’s quieter and more efficient at lower speeds, and less smelly. It’s also expected to lower costs of ownership by reducing or eliminating the needs for oil and transmission fluid changes, filter and impeller replacements, and starter problems. There’s less to winterize, too. Unlike with diesel or gas engines, electric motors provide full torque instantly and repower conversions, which currently make up the lion’s share of the market, can use existing drive shafts and components to save cost.
Technology Game Changers
Use of brushless permanent magnet electric motors and advances in lithium ion battery technology have allowed for leaps to be made in the rush to marine e-propulsion. Currently, two approaches are battling it out on the water: serial and parallel hybrids.
The serial hybrid system integrates a range-extending generator. The engine drives the generator, which powers an electric motor connected to the driveshaft; there is no mechanical connection between the engine and the driveshaft.
A parallel system has a direct mechanical connection between the engine and the driveshaft, but also contains—on the same shaft—an additional electric motor (or a standby diesel engine) acting as a generator. Regeneration may be accomplished by running the diesel for a short period of time, or, to avoid fuel completely, by implementing a free-spinning propeller. This propeller spins easily on a boat under sail or while using only one engine on a powerboat, recharging the system. Almost all automotive hybrids are parallel systems, including the Toyota Prius.
Who’s Who?
By far, the manufacturer that has done the most in terms of e-propulsion branding is Torqeedo based in Gilching, Germany. They started 15 years ago with simple outboard technology and have expanded to high voltage systems for large inboard applications. Another contender is Elco from Athens, New York, which began with small outboards but is also reaching into the coveted inboard market.
Others include the Finnish OceanVolt, Italian Diesel Center, American Electric Yacht, and British Hybrid Marine. California-based Electroprop sells pre-packaged 6- and 21-kW systems that boat builders can drop into their engine rooms. Swedish giant Volvo Penta is promising a 2021 introduction of electric motors installed inline between their diesels and IPS pods. Currently, their test bed is a Fountaine Pajot Lucia 40 sailing cat.
Energy Storage
Of course, it’s not all just about motor manufacturers. Battery makers such as Mastervolt and NexGen and monitoring specialists like Victron and Simarine are working on how to store and manage the energy in newfangled lithium ion battery systems that can charge quickly, discharge efficiently, and have a long life in a harsh environment.
Torqeedo teamed with BMW and marinized their i3 and i8 Series auto batteries for use in a variety of boats. For example, with two stacked i3 Series 40 kW batteries and a high-rpm 100 kW Deep Blue inboard motor, a 25-foot Frauscher Mirage 740 Air can reach 25 mph at 2200 rpm and have a 20-mile range. Clearly, electric propulsion is no longer the domain of slow harbor cruisers, tenders, and sailboats.
Hurdles to Fast Progress
So with new battery and motor technology, why isn’t this growing faster? One reason is boater acceptance. Repowering is expensive and the technology is still murky so boaters are curious but cautious.
Service is another hurdle. Who is trained to fix this in case your fairly complex system breaks down? The number of servicing dealers is growing, albeit slowly. Hybrid Marine is building their service network and Torqeedo has approximately 100 service centers around the globe. The challenge and expense of creating a service network has put extra importance on monitoring, diagnostics, and software updates that can be done remotely.
Finally, there’s the problem of infrastructure, which is the same for automotive: What is the range for a fully-electric vessel and where does it recharge? Just like a Tesla that you’d probably not take on a cross-country road trip, a boat that needs charging stations that are close together and can “fuel” the vessel quickly will limit its range.
Outlook
Customers are definitely interested in e-propulsion since there’s been a confluence of improved components. Electric and hybrid propulsion is about making mobility “lower-carbon” now and “carbon-neutral” in the future and it will grow, if only due to necessity.
Today’s early adopters are the technologists and visionaries but they make up only about 15% of the market. In marine, these are distance sailors that need efficient sustainability but they’re also ferries and water taxis that operate on bodies of water like lakes and rivers where combustion engines aren’t allowed.
The next 70% of the bell curve is where the money will be made and it can be everything from light daysailers and fast tenders to the boating sweet spot of the 25-75 foot midrange power market. This last segment is still up for grabs and there are numerous manufacturers vying for a chance to own it.
E-propulsion for automobiles is expected to grow at compounded rate of 53% and by 2040, nearly half of cars are expected to be plug-ins or hybrids. With a little education about myths and reality, maybe we can get boating to ride that wave as well.
About the Author
Zuzana is a freelance writer and photographer with regular contributions to over 18 sailing and power boating publications. A USCG 100 Ton Master, Zuzana is the founder of a flotilla charter company called Zescapes that takes guests adventure sailing at destinations around the world.
Zuzana serves as an international presenter on charter destinations, safety issues, and technical topics, and she's the Chair of the New Product Awards committee for innovative boats and new gear. She is a member of the American Society of Authors and Journalists and a board member of Boating Writers International.
This article first appeared in the Spring Issue (Mar/Apr) 2020 of Great Lakes Scuttlebutt magazine.
tags: Boating 101, Engines, Environmental Impact, Generators
