Nearly two years ago, Sandia National Laboratories researchers Joe Pratt and Lennie Klebanoff set out to answer one not-so-simple question: Is it feasible to build and operate a high-speed passenger ferry solely powered by hydrogen fuel cells? The answer is yes.
The details behind that answer appear in a recent report, “Feasibility of the SF-BREEZE: a Zero Emission, Hydrogen Fuel Cell High Speed Passenger Ferry.” SF-BREEZE stands for San Francisco Bay Renewable Energy Electric Vessel with Zero Emissions. Pratt and Klebanoff found that it is technically possible to build a high-speed, zero-emission hydrogen-powered ferry that they say can also be done with full regulatory acceptance.
Tom Escher, president of San Francisco’s Red and White Fleet, first conceived of the project when he asked if it was possible to do away with emissions altogether on one of his ferries. “This is a game changer. We can eliminate environmental pollution from ships,” he says. “This could have a major impact on every shipyard in the country.”
Funded by the Department of Transportation’s Maritime Administration and led by Sandia, the feasibility study brought together the American Bureau of Shipping (ABS), the US Coast Guard, naval architect Elliott Bay Design Group, the Port of San Francisco and dozens of other contributors.
“Not long ago, the prospect of pollution-free transportation seemed like science fiction,” says Paul Jaenichen, an administrator at Maritime Administration. “Today, through public-private collaboration on projects like SF-BREEZE, we are making progress to turn it into a reality.”
The research group drew up conceptual specifications for a 150-passenger commuter ferry that would travel four 50-mile round-trip routes each day at a top speed of 35 knots (roughly 39 miles per hour) about 60 percent of the time. The ferry could refuel midday, between the morning and afternoon commutes.
“This kind of boat has never been built before,” said mechanical engineer Curt Leffers, project manager for Elliott Bay Design Group. “Hydrogen fuel cells are heavier than diesel engines for a given power output, so achieving the right power-to-weight ratio for the vessel was tricky.”
The need for speed drove the design to a slightly longer catamaran, but the engineers were able to save weight by consolidating the support equipment for the fuel cells. To achieve the necessary safety standoffs from the fuel cells, engineers placed them on the main deck of the vessel in a separate compartment, a design Leffers says provides physical separation between the fuel cells and passengers.
The project also supports Elliott Bay’s commitment to the environment. “I’m a big believer in developing environmentally friendly designs,” Leffers says. “This project has been terrific because it’s something I really believe in. I think that this proof-of-concept, that this boat can be built, is very important for future projects.”
ABS issued a conditional Approval in Principle to verify that the conceptual design would be compliant with applicable regulations and rules and to identify any potential gaps in compliance. Combining the assessment with feedback from the US Coast Guard, Sandia found no regulatory show-stoppers and concluded that the vessel will be acceptable from a regulatory perspective once a more detailed “ready-to-build” design is generated.
“ABS is proud to have participated in the SF-BREEZE feasibility study and to have advanced the research on unique challenges of designing a high-speed passenger ferry powered solely by hydrogen fuel cells,” says Howard Fireman, ABS CTO. “The collaboration with Sandia and the project team extends our knowledge base and the potential technology transfer to address the challenge of reducing the environmental footprint.”
The hydrogen ferry would cost about twice as much as a comparable diesel ferry with today’s prices, with much of that cost stemming from the fuel cell system.
“Right now, we can’t achieve economic parity with a comparable diesel ferry,” says Pratt. “But this is a question we need to explore further. Is economic parity necessary from the outset? Lessons from the automotive market tell us maybe not.” Vehicle manufacturers have successfully brought fuel cell electric vehicles to market even though those cars are more expensive than comparable internal combustion engine vehicles. Many experts expect mass adoption of fuel cell electric vehicles to bring down prices of hydrogen fuel cells.
The next step is to optimize the vessel design. “We need to consider if the parameters we started out with are optimal for the technology that is available today,” says Pratt.
Working with Red and White Fleet and other stakeholders, Klebanoff and Pratt are now undertaking an optimization study. They will examine the tradeoffs between speed and costs and emissions among other factors.
Red and White Fleet President Escher sees SF-BREEZE as the start of a revolution in marine transportation. “When this boat is launched, it will be a seed. When you add a seed to water, it grows,” he says. “This seed could grow into a 40-meter tugboat, a 70-meter supply boat or a 300-meter oceangoing ship trading between the West Coast and Hawaii. And all at zero pollution.”