Two vessels that will operate on the West Coast are pioneers in the maritime industry’s push to adopt zero-emissions propulsion.
In mid-August, All American Marine launched the 70-foot Sea Change, a 75-passenger ferry powered entirely by hydrogen fuel. It will operate in San Francisco Bay, becoming the first commercial ferry in the world powered by hydrogen fuel cells, according to Zero Emission Industries (ZEI), which designed the vessel’s powertrain.
And in July, the California Legislature approved $35 million to design and build a hybrid hydrogen-fueled research vessel. It will replace the 40-year-old vessel Robert Gordon Sproul at the Scripps Institution of Oceanography at the University of California, San Diego. Designing and building the 125-foot vessel, which will integrate fuel cells alongside a diesel-electric power plant, will take about three years.
Two studies, both led by Sandia National Laboratories, laid the groundwork for hydrogen fuel within the maritime industry. One from 2016 concluded it was technically possible to build a high-speed hydrogen-powered ferry. The other, released in 2018, determined a hydrogen-powered research vessel was feasible.
Sea Change is completely powered by hydrogen fuel. The fuel cell power package was developed by ZEI. The fuel cells are made by Cummins Hydrogenics with 360 kW of capacity. The hydrogen storage tanks, made by Hexagon Purus, can hold 246 kilograms of compressed gas, enough for two days of operation. The passenger ferry can go 22 knots with a power boost from 100-kWh batteries, according to ZEI. Two 400-hp shaft motors built by BAE Systems provide the propulsion.
The placement of the fuel cells in the ferry was not a challenge. The hydrogen modules don’t have to be located next to each other, according to Danny Terlip, lead engineer for ZEI. However, for Sea Change, there are 12 30-kW modules located in a single room on the forward deck. The hydrogen fuel tanks are on the roof of the ferry behind the pilot house.
Hydrogen fuel cells work like batteries, but they do not need recharging. A fuel cell has two plates stacked together, with an insulator in between, Terlip said. One plate is a negative electrode and the other a positive electrode. Hydrogen goes through the negative electrode, called the anode, and oxygen goes through the positive electrode, called the cathode. The insulator between the plates has a catalyst made from an alloy with platinum, according to Terlip. This process causes a reaction that produces electricity, water and heat.
Bruce Applegate, head of ship operations at Scripps Institute of Oceanography, has worked on the hydrogen-powered vessel concept since 2014. Collaborators include Sandia Labs, DNV Maritime and naval architects at Glosten. Although an entirely hydrogen-powered vessel was considered, it was not possible to store the amount of fuel needed for the 2,500 nautical miles covered by some trips. With the hydrogen-hybrid propulsion system, the vessel still produces zero emissions with 75 percent of trips projected to sail only using hydrogen fuel, according to Scripps.
Initially, loading the fuel was a challenge. “A big thing we learned on the first study was that we had no idea how to bunker these things,” Applegate said. They thought a multi-modal terminal would have to be built, costing millions of dollars. But Applegate said that land-based hydrogen systems in California are replenished using trucks. Refueling the research vessel could be done just as it is now for diesel fuel. “We just drive a truck out onto the pier, throw a hose over and bunker it that way,” he said.
The bunkering solution for Sea Change was equally simple. “We put all of the bunkering hardware on the boat, and then we can, anywhere there’s a truck, just refuel,” Terlip said. “And that allows us to meet any fueling source wherever they are and refuel.”
Although all-electric or hybrid electric-diesel vessels are the latest trend, Ron Wille, All American Marine’s president and CEO, said batteries that now provide all-electric power are too heavy. “My analogy has been, when you have a battery-powered boat, you can neither go far nor go fast,” he said. “A hydrogen-powered vessel, in theory, has the ability to go far and fast.”