The plan to build an offshore wind farm to provide energy for the South Fork has received approval by the state comptroller, with a listed price tag to ratepayers of more than $1.62 billion.

The contract value listed on the comptroller’s website — specifically $1,624,738,893 — encompasses the anticipated cost of all energy from the 15 turbines over its 20-year contract. That makes it the fourth most expensive energy contract in the LIPA portfolio, after all National Grid plants at $5 billion, the Neptune cable on the South Shore at $1.75 billion, and the Caithness plant in Yaphank at $1.67 billion.

The Deepwater contract is for the purchase of energy from the wind farm, while the other LIPA contracts cover capacity from the plants — essentially lease agreements — exclusive of the cost of energy.

Deepwater officials have said the plant located off the Rhode Island coast will cost around $740 million to build, including a 50-mile cable to East Hampton, and will provide around 370,000 megawatt hours of energy a year. Newsday previously estimated the 20-year contract cost at around $1.46 billion. LIPA officials have said they expect the plant to be operating by the end of 2022.

At 90 megawatts, the wind farm will be among the lower power producers in LIPA’s portfolio, albeit the cleanest. The National Grid contract provides for around 2,200 megawatts and the Neptune cable, around 660 megawatts. Caithness is rated at around 350 megawatts. A megawatt from a power plant powers from 800 to 1,000 homes, but the figure is about half or less for offshore wind, because wind blows intermittently.

A comptroller’s spokesman confirmed last week’s approval but declined to comment on it. A spokesman for LIPA didn’t provide a comment.

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Deepwater chief executive Jeff Grybowski said the company has already started a “multiyear permitting process” needed before construction can begin. It will conduct marine surveys in Block Island Sound starting this summer, and land and water surveys for the cable to Long Island.

Approval by the state comptroller and the state attorney general mean that Deepwater will be able to move forward to reach milestones this year that will make it eligible for more than $170 million in federal tax credits. Grabowski said he was confident the project will qualify for the tax credit.

Environmentalists and a majority of Long Islanders support the offshore wind farm located more than 10 miles from the coast, according to a recent poll, but commercial fishing groups oppose it, saying it could damage the sea bottom, harm wildlife and close off fishing grounds.