The Steamship Authority ferry M/V Island Home will be running on renewable diesel this summer, in a pilot program that could result in switching the entire fleet to the low-emissions fuel.

Known as RD-99 or hydrogenated vegetable oil (HVO), the diesel is made from vegetable oils and other fats. It has been used in California for years and is newly available in New England. At the joint meeting of the ferry line’s board and port council last week, Steamship chief operating officer Mark Amundsen said the new fuel could result in a 50 to 70 per cent reduction in greenhouse gases.

“This is a real game changer for us, as this fuel is now available on a year-round basis going forward,” he said.

The new fuel will run much like petroleum-derived diesel in the ferry’s engines, Mr. Amundsen said.

“We’ve gone to all the manufacturers, and they have given the green light on this,” he said.

The renewable fuel can even be mixed with standard diesel, Mr. Amundsen said.

The sole difference in performance is that petroleum diesels run a bit hotter, producing 132,000 BTUs (British Thermal Units) compared to 128,000 BTUs for the veggie diesel, Mr. Amundsen said.

“There’d be a slight [increase in] consumption,” he said.

At $2.99 a gallon, delivered, the renewable fuel also costs more than the low-sulfur diesel the Steamship Authority currently buys at $2.40 a gallon.

But if the Island Home trial is successful, these negatives would be outweighed by the advantages of switching the whole Steamship Authority fleet to fossil-free fuel, Mr. Amundsen said.

“Given the benefits of this, we’re really looking forward to this being part of our future,” he said.

James Malkin, who represents Martha’s Vineyard on the Steamship board, expressed enthusiasm at Mr. Amundsen’s news.

“This is a big thing for us. This is a big thing for the community,” Mr. Malkin said.

The Steamship Authority has been under heavy pressure, from the public and state policy, to electrify its fleet. 

Citing costs and logistics, including access to sufficient power in port towns, boat line officials have said that full electrification remains years in the future.

“People just don’t realize the power required in four, five locations,” Mr. Amundsen told the Gazette in a follow-up conversation.

Until then, if the pilot program is successful, the vegetable diesel would allow the Steamship Authority to run a greener fleet, Mr. Amundsen said.

The board voted unanimously to run the Island Home exclusively on RD-99 from June 1 to Sept. 1, after which Mr. Amundsen and the SSA engineering staff will assess the fuel’s performance.

“Then, if we get board approval, we’re going to do a complete switch-over for the fleet,” he said.

The boat line also would need to ensure it can get all the RD-99 it needs, as other transit agencies — including Boston’s MBTA — also are giving it a try this summer, Mr. Amundsen said.

“We’re working on hedges for this as well,” he said, referring to the SSA’s practice of pre-booking fuel supplies at a fixed price.

“We’ve got to look at the long-term supply chain,” he said.