Op-Ed: Hydrogen fuel cells for small boats

Sea Change, the world's first hydrogen fuel cell ferry. ZEI provided the hydrogen fuel cell system for the ferry.

By Mark Stott, head of customer solutions, and Carter Anderick, product marketing manager, ZEI

The global maritime industry is poised for a dramatic change. Responsible for nearly 6% of global emissions, the maritime industry faces pressure from governing bodies to enact an impactful and lasting change. Marine diesel engines greatly impact the marine environment, creating devastating amounts of air, water and noise pollution. Governments worldwide have declared that maritime transportation needs a radical overhaul. But how does an entire industry realistically evolve when inherently resistant to change? Regardless of what can be done to reduce diesel engine emissions from their current levels, more impactful change is the only way forward.

Enter the working small boat market. Given their proliferation throughout marine environments of all types around the world, decarbonizing these vessels stands to have a profound impact on cleaning up maritime emissions. However, mission demands, performance requirements, and conditions of use make simple electrification not an option. The only practical, real-world, and impactful solution to decarbonizing small boats is hydrogen fuel cell power.

To further understand “small boats,” let’s focus on the example of first responder craft under 50 feet in length. With high annual hours and unforgiving missions, they are critical to maintaining our infrastructure, safety and security. The operational profiles of patrol, firefighting, search and rescue, and security boats are highly demanding and unpredictable. A police boat, for example, could at any given moment be patrolling a port, responding to a boating emergency, or participating in a multi-day search and rescue operation. These mission-critical public safety vessels have short response times, a wide variance in operational speeds, range, endurance, and require rapid turnaround time to do it all over again. We rely on first responder boats to always be part of the solution, not the problem, leaving little room for compromise on any of the above criteria.

Further emission reductions in diesel engines are incremental at best, and to achieve true environmental impact and sustainability, the marine industry must follow the automotive industry toward electrification.  In the past decade-plus, battery electric road-going vehicles have driven significant advancements in battery, inverter, and electric motor technology. The duty cycle of a passenger car, however, which can cruise using minimal power, coast, and regenerate power during braking and deceleration, is vastly different from that of a boat, which requires continuous power in great quantities just to remain in motion. Even medium and heavy-duty trucking—formerly reliant on the same diesel engine platforms used in many boats—are moving to hydrogen fuel cells as the only viable electrification alternative.

Battery electric and hydrogen fuel cell boats share several common drive-train components, including battery, inverter and electric motor, but the big difference is in energy storage and replenishment. Battery-only electric vessels store all of their energy in battery banks where extended range or power comes at the cost of considerable weight, recharge time and the limitations of power grid capacity. Conversely,  hydrogen fuel cell vessels store most of their energy in rapidly rechargeable hydrogen tanks. The hydrogen is then converted to electricity in the fuel cell stack, with clean water vapor as the only emission.

Hydrogen fuel cell engines make sense for marine applications for many reasons. Boat designers and builders are increasingly familiar and comfortable with the concept of the “electrification” of propulsion systems thanks to several commercially available options. Electric motors—whatever their power source—have impressive torque figures, with significant reductions in vibration and noise relative to diesel engines. These are tremendous upsides to boat builders and operators. The same hydrogen fuel cell engines being produced and optimized for the trucking industry are inherently conducive to marinization, having a similar form factor and power to their diesel counterparts.  Marine hydrogen fuel cell engines also rely on the same installation considerations as a current diesel engine, i.e. fuel, air, raw water and exhaust. In addition, hydrogen as a fuel has less than one-third of the weight of diesel for the equivalent amount of energy, providing boat designers and builders with expanded options for fuel storage locations with less effect on vessel stability between a full and empty fuel condition.

The task of marinizing any piece of equipment is a difficult one, especially those intended for saltwater applications. The demanding needs of small boats in high-hour, critical service makes that process even more difficult and expensive unless the dedicated expertise exists to bring dependable hydrogen power into these applications. Zero Emission Industries exists to solve these challenges. ZEI is committed to the development and production of marine hydrogen fuel cell engines to drive the marine industry into a sustainable, emission-free future.