Mayflower Wind Energy – a joint venture between Shell New Energies and Portuguese utility EDPR – scored a key breakthrough in the fast-moving US offshore wind market after it was selected by Massachusetts in its second tender to supply 804MW capacity.

To do this, Mayflower will build an array, sited in a zone about 32km (20 miles) from the state’s southern coast, which it expects to enter commercial operation in 2025. Last December, the developer paid a record $135m in a competitive lease round for development rights and site control in federal waters.

Mayflower anticipates the project – it did not provide a cost estimate – will provide various economic benefits for ratepayers and the state economy.

These include long-term prices below the original price cap of $84.23/MWh, $3.7bn in electricity rate reduction over the contract term; creation of up to 10,000 jobs in Massachusetts in both offshore jobs and onshore opportunities; and elimination of 1.7 million metric tons of CO₂ emissions annually from clean energy produced once online.

Mayflower president John Hartnett said the project would contribute to the building of an offshore supply chain on Massachusetts South Coast and across the state.

The developer said it would draw on the "deep skills" of its parent companies and also their experience with developing, permitting, financing, constructing and operating both offshore wind facilities in Europe and those onshore in the US. EDPR is a leading US onshore wind capacity owner.

Mayflower's bid won over those submitted by Bay State Wind – owned by Orsted and Eversource, the largest energy supplier in New England – and Vineyard Wind, a JV between Avangrid and Copenhagen Infrastructure Partners, which won the state's first offshore tender and whose eponymous 800MW under-development project is the nation's first at commercial scale.

"During the bid process, Mayflower Wind proposed wind energy at a more competitive price with greater economic development opportunities for the Commonwealth and the South Coast than any other bidder," the Massachussetts Executive Office of Energy and Environmental Affairs said in a statement.

Criteria used in the evaluation of bids included an economic evaluation of the benefits for ratepayers; the project’s ability to foster employment and economic development in Massachusetts; the project’s environmental impacts, and the extent to which a project demonstrates that it avoids or mitigates impacts to regional commercial fisheries.

The distribution companies and Mayflower will now negotiate supply contracts by a 13 December deadline and those must be approved by regulators at the Massachusetts Department of Public Utilities.

“With today’s announcement of additional, cost-effective offshore wind energy, the Commonwealth continues to be a national leader in this industry,” said Massachusetts Governor Charlie Baker in a statement.

As directed by the state legislature, the Department of Energy Resources released an offshore wind study that recommended and the distribution companies to proceed with additional offshore wind solicitations for up to an additional 1.6GW capacity – if found cost-effective at the time of solicitation.

Liz Burdock, CEO of industry body the Business Network for Offshore Wind, said: “Major oil & gas companies and utilities understand the future of electricity generation along the US Coast is offshore wind.

“The selection of Mayflower Wind, [being] a joint project between oil & gas giant Shell New Energies and the Portuguese utility EDP Renewables, truly demonstrates the rush to fuel supply diversification. This team will bring regulatory expertise and utilise a supply chain that will expand across America.”

In June, Shell took the plunge in the US market by partnering with EDF to submit a bid in New Jersey's initial 1.1GW offshore wind capacity allocation but lost to Orsted.

· Adds quotes from BNOW's Liz Burdock

Wind

Shell-EDPR score major US offshore wind project breakthrough