US offshore wind joint venture (JV) Mayflower Wind has acquired a 1.2GW interconnection queue position from independent grid operator Anbaric at the retired Brayton Point coal-fired power plant site south of Boston, Massachusetts while also announcing it will employ high-voltage direct-current (HVDC) offshore wind transmission technology for developments beyond 804MW capacity contracted with the state.

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The deal – financial terms of which were not made public – further positions the Ocean Winds-Shell New Energies JV to bid in the state’s present 1.6GW tender and future rounds for an additional 2.4GW of capacity. Massachusetts’ procurement structure now requires bundled generation plus transmission projects.

Massachusetts – and New England more broadly – has a limited number of larger capacity interconnection points that are filling up as more offshore wind capacity is awarded, and developers are rushing to tie their projects with those easiest and cheapest to access. Connecticut and Rhode Island have also awarded 1.5GW of capacity between them.

The 1.25km2 Brayton Point waterfront site, located 85km (53 miles) south of Boston, is especially attractive because there is space onsite for a planned large HVDC converter station, 400MW-plus battery storage, other infrastructure, plus an established transmission link to the Greater Boston area.

“We now own the queue position up to 1.2GW,” Seth Kaplan, director of external affairs at Mayflower Wind, told Recharge, noting that regional grid operator ISO New England (ISO-NE) does not want larger individual queue positions. “We’re really happy to have this asset.”

“Anbaric had the vision to put an elective transmission upgrade into the ISO-NE queue. They filed the interconnection request and have been progressing it through that process. Moving it forward to an interconnection agreement and acquiring rights,” he said.

Included in the transaction is related project development work done by Anbaric such as property rights, routing, technical design and the HVDC converter station, Peter Shattuck, president, New England, for Anbaric, told Recharge.

“We are committed to seeing the project succeed, and to working with Mayflower through the interconnection process. Mayflower will ultimately construct and own the project,” he said, referring to the Brayton Point transmission infrastructure. The site is owned by Commercial Development Company, a brownfield real estate developer based in St. Louis, Missouri.

Kaplan claimed the transaction will be a pacesetter for the US offshore wind industry: “It’s the first instance where a generation project purchased a mature 1,200MW interconnection position for their project.”

He clarified that the JV views its offshore wind lease area as one project at different stages sending power to several interconnection points, according to off-take agreements with Massachusetts electric distribution companies.

The deal represents a vote of confidence from Mayflower’s two owners, said Kaplan, adding that Ocean Winds and Shell “are standing behind this project and taking really tangible steps to progress it”.

In 2019, Mayflower won the state’s second offshore wind tender for 804MW capacity with a US industry record low bid. That power will be exported point-to-point using an alternating current (AC) radial line about 93km (50 nautical miles) in length to landfall at Falmouth, Cape Cod.

“It’s all a function of distance,” said Kaplan, noting that Brayton Point at 130 km or more is further way from Mayflower’s lease area south of Massachusetts than Cape Cod. He added that any future contract for a greater amount of capacity would also be a factor in opting for a HVDC transmission system which will minimize marine cabling, reduces energy losses, and strengthens the New England grid.

“When fully built out, and with continuing advancements in wind technology, Mayflower Wind’s lease area will supply over 2,000MW of offshore wind, enough to power nearly a million homes,” the joint venture said in a statement.

Mayflower is the second offshore wind developer in the US to publicly embrace HVDC technology after Norway’s Equinor and BP for their future contracted 1.23GW Beacon Hill 1 project, as exclusively reported by Recharge.

There are currently 1.7 million acres (688,000 hectares) under lease spread across 16 zones on the US outer continental shelf. This translates to 21GW of potential capacity for those lease areas using the National Renewable Energy Laboratory’s power density calculator for offshore wind.

Ealier this year, President Joe Biden's administration set a “national goal” to have 30GW of turbines spinning offshore by 2030 in the US Atlantic.