Vineyard Wind, the international business consortium that plans to build the nation’s largest offshore wind farm 15 miles south of Martha’s Vineyard, has been hit with yet another delay after a federal agency moved back its review timeline for a key permitting document last week.

The $2.8 billion dollar offshore energy project was originally expected to have its Final Environmental Impact Statement (FEIS) completed earlier this week, with a final recorded decision before the New Year. The impact statement is required before the federal government can make a decision on the project.

But the Bureau of Ocean Energy Management — the federal agency responsible for issuing the environmental impact statement and permitting the project — updated its timeline late last week, moving back the expected date for the final impact statement to Dec. 11. The BOEM online timetable for Vineyard Wind now lists Jan. 15, 2021 as its expected date to issue a formal record of decision on the development.

A BOEM spokesman said in an email that the agency is still reviewing a mountain of correspondence related to the project.

More than 13,000 comments were received during a public comment period on the supplemental environmental impact statement, the spokesman said. “BOEM continues to work with cooperating agencies in the review of these comments.”

The expected decision date is less than a week before the Trump administration is slated to leave office. The timetable now states that the final completion of all permitting and environmental review on the project is expected by March 18, 2021.

Despite the setbacks, as the race to build offshore wind farms heats up, Vineyard Wind remains on track to be the first industrial-scale wind farm in the United States.

Headquartered in New Bedford, the company is a joint, 50-50 venture between Copenhagen Infrastructure Projects and Avangrid Renewables.

In an emailed statement, a spokesman for Vineyard Wind said the delay would not affect the timeline for the project, which is expected to be online by 2023.

“Minor delays like this are not uncommon and we look forward to publication of the FEIS on Dec. 11,” spokesman Andrew Doba said. “We are confident that we’ll be able to make the investment decision by mid-2021 as planned and deliver the project in the announced time frame.”

Vineyard Wind 1, as the project is formally known, includes the construction of approximately 80 turbines and two undersea cables that will connect the wind farm to mainland Cape Cod at a switching station in Barnstable. The undersea cables will run about a mile east of Chappaquiddick.

The project is expected to generate 800 megawatts of wind energy and power up to 400,000 homes in southeastern Massachusetts.

Mayflower Wind, which plans to build a wind farm in a federal lease block southeast of Vineyard Wind, has also recently begun its permitting process.

Vineyard Wind has now received all its requisite state and local permitting, after a process that was bumpy at times. The Edgartown conservation commission denied the undersea cable part of the project but later reached agreement with the wind farm developers for the cable.

Concerns from fishermen and marine navigation have slowed the permitting process at both the state and local level.

Federal permitting has been even more of a challenge for Vineyard Wind, which has been hit with numerous delays to the final environmental impact statement over the past 18 months after federal regulators said they would evaluate the project in the context of cumulative impacts of all planned offshore wind development along the Atlantic coast.

The change forced BOEM to issue a new supplemental impact statement that considered the project’s impacts within the broader ecosystem of all future coastal wind development. A draft of the statement was released this past summer.

The most recent delay comes just as Vineyard Wind signed an agreement with ISO New England to deliver energy to the grid once the project comes online. The company had already been cleared to enter into power purchase agreements with state electric distribution companies.