The extension project is located about 19km off the English east coast, next to the 367MW Walney offshore wind farm.
Covering an area of about 149km², the extension project will be developed in two phases, each with a power generation capacity of 330MW.
As part of the deal, Seajacks Scylla vessel will undertake installation work of 40 units of MHI Vestas V164 8.2MW and 47 Siemens SWP-7.0-154 turbines across both phases of the project.
Mobilisation is due to take place in early summer 2017 and Scylla is under construction in South Korea.
The vessel will be fitted with an adaptable blade rack and seafastening solution which Seajacks claims is rapidly interchangeable between the MHI Vestas and the Siemens turbines.
The contracts associated to project are subject to Dong Energy’s final investment decision.
Seajacks UK CEO Blair Ainslie said: "With Scylla, DONG Energy have chartered the largest and most capable vessel in the market which will enable them to transport and install the largest most powerful of new turbines at the deepest and most demanding of high wind locations."
UK Energy Minister Andrea Leadsom said: "It’s great to see Dong Energy selecting a British business, Seajacks, to help install the turbines for its Walney Extension offshore wind farm.
"The UK is open for business and this new contract will support growth and local jobs, providing lasting economic security for working people."
After completion, both the Walney wind farms will generate enough electricity for more than 800,000 households.
The wind farms will contribute to the UK’s goal of generating 15% of its total energy from renewable sources by 2020.
Image: Seajacks Scylla vessel will be deployed on the Walney Extension offshore wind farm project. Photo: courtesy of Seajacks.
