Angel Island-Tiburon Ferry aims to become state’s first electric short-run ferry

Marin County’s family-owned Angel Island-Tiburon Ferry Co. may soon become California’s first all-electric short-run ferry service.

The company owned by Capt. Maggie McDonogh is aiming to convert its existing 400-seat, 59-foot ferry from diesel power to electric propulsion in 2024 through a partnership with San Rafael-based Green Yachts company and Pacific Gas and Electric Co.

Angel Island-Tiburon Ferry Co. would be the first to meet a state mandate requiring new and existing short-run ferry services to become zero-emission by the end of 2025.

“It’s going to have zero emissions and we won’t be polluting our local community,” McDonogh said. “None of the emissions are going into the East Bay and into disadvantaged communities.”

The transition away from diesel power will require significant investments, an increase in electrical transmission and the fortitude to wade through an uncharted regulatory landscape, Green Yachts managing broker Graham Balch said.

“One thing that is interesting about boats as well is that it takes about 1,500% more energy to move an electric vessel 1 mile compared to an electric semi-truck and takes 15,000% more energy than to move an electric car one mile,” Balch said. “That’s what makes marine electrification difficult.”

However, Balch said passengers should not experience any changes to the existing 10-minute travel time between Tiburon and the island.

The project is estimated to cost $4 million, which is about 10 times more than it would take to transition to a lower-emission diesel engine, Balch said. Additionally, the company will need to gain approval from the U.S. Coast Guard.

As a private company, McDonogh said her outfit is unable to qualify for certain federal funds compared to other larger ferry operators in the San Francisco Bay Area such as the Golden Gate Bridge district. So far, the company has raised about a third of the funding needed and is hoping to acquire more through grants through the California Air Resources Control Board this year.

The transition to electrical power goes beyond replacing the ferry’s 290-horsepower diesel engines with a 170-kilowatt electric motor and installing battery banks.

PG&E will need to bolster its electricity transmission to the ferry terminal and install charging equipment that can provide enough power for the ferry.

The utility company’s spokesman Mike Gazda said the ferry service is the only marine vessel currently participating in its electrical vehicle fleet program. As part of the program, PG&E builds and maintains all electrical equipment from the transformer to the customer’s meter, while the participating business or agency maintains everything from their meter to the charging equipment.

“The electrification of the Angel Island vessel aligns with our core focus of proactively preparing the grid for the future, increasing access to charging infrastructure, and supporting electric transportation adoption through rates, rebates, tools, and education,” Aaron August, PG&E’s vice president of utility partnerships and innovation, said in a statement.

The new electric ferry would be able to complete all of its trips on one charge. However, doing so would degrade the battery, similar to how a laptop battery is degraded when it runs out of power, Balch said. The plan is to charge the ferry in between trips, which Balch said requires a greater amount of electricity transmission to make possible.

The ferry service has already been working for nearly two years to prepare for the change, but McDonogh said she feels the challenges will be worth the effort.

“Doing the right thing for the greater good isn’t always the easy thing to do,” McDonogh said. “It can be tremendously hard to do. But it’s always the right thing to do.”

The California Air Resources Control Board is requiring the transition away from diesel power because of ferry vessels’ emissions of tiny particulate matter — specifically what is known as PM 2.5 — that has been linked to various health effects including respiratory disease and heart attacks, according to the U.S. Environmental Protection Agency. Under its rules, the state board aims to reduce particulate matter emissions from ferry vessels by 85% and reduce nitrogen oxide emissions — a greenhouse gas — by 68% by 2031.

The zero-emission requirements only apply to short-run vessels, which the state defines as vessels that “provide regularly scheduled ferry service between two points that are less than three nautical miles apart.”

For all other ferries, the state board is requiring that they upgrade to Tier 4 diesel engines, which have the strictest federal emissions standards, between 2024-2029 with possible extensions through 2034.

Electrifying the San Francisco Bay’s main commuter ferry service operated by the Golden Gate Bridge district will be a greater challenge.

District spokesman Paolo Cosulich-Schwartz said that the short and slower trips such as those provided by Angel Island-Tiburon Ferry Co. lend themselves more to electrification. By comparison, Golden Gate ferries travel faster over distances of more than 10 miles.

“At the moment, electric ferries are significantly slower than what we provide,” Cosulich-Schwartz said.

With existing technology, the 30-minute trip from Larkspur to San Francisco would take closer to an hour with an all-electric ferry, Cosulich-Schwartz said. The district’s ferries also have a quick five-minute turnaround time, which under an all-electric system would be a challenge given the need to charge them. This would likely require the district to purchase more ferry vessels and require large investments at the ferry terminals.