Transformers for First US HVDC Offshore Wind Grid Connection Arrive in New York

The four transformers for the substations that will receive and transmit the electricity produced by the Sunrise Wind offshore wind farm to the mainland have arrived in New York, according to a social media post by Siemens Energy, which is supplying the high-voltage direct current (HVDC) transmission system for the 924 MW offshore wind project in a consortium with Aker Solutions.

According to the project developers Ørsted and Eversource, Sunrise Wind is the first offshore wind project in the US to use an HVDC system.

Under a contract awarded in 2021 to the consortium between Siemens Energy and Aker Solutions, Siemens Energy is responsible for delivering the system on a turnkey basis and providing onshore civil work in partnership with local companies, and Aker Solutions will deliver the offshore platform which consists of a steel jacket substructure, and a topside platform deck housing the electrical equipment.

Sunrise Wind’s HVDC transmission system consists of two converter stations, one offshore and an onshore substation, and a subsea export cable that will connect the wind farm’s offshore substation to the grid connection point on land.

The offshore converter station will collect the 66 kV alternating current (AC) power generated by the wind turbines through an inter-array cable system and transform it to 320 kV DC for transmission through the export cable to the onshore converter station at Holbrook on Long Island. The onshore substation will then convert the power back to AC to feed it into the distribution grid.

Located approximately 30 miles (about 48 kilometres) east of Montauk, New Jersey, Sunrise Wind will generate enough clean energy to power nearly 600,000 New York homes, once it is completed in 2026.

Ørsted is set to soon become the sole owner of the offshore wind farm after agreeing to buy Eversource Energy’s 50 per cent stake. Following the completion of the transaction, expected later this year, Eversource will remain contracted, under a separate construction management agreement, to lead the onshore construction of the Sunrise Wind project. In this role, Eversource will be a service provider to Ørsted.