Orsted has placed an order with Siemens Gamesa for the 165 turbines that will make up its record-breaking Hornsea Project Two offshore wind farm.

Once operational in 2022, Hornsea Project Two will overtake its sister, Hornsea Project One, to become the biggest offshore wind farm in the world.

The 8MW turbines will have 81-metre-long blades and a rotor diameter of 167 metres – the largest currently available on the market.

Siemens Gamesa was selected as the turbine supplier for the project back in March. The deal represents the largest single order in the history of the offshore wind industry. Three quarters of the blades will be manufactured at the company’s factory in Hull.

Located 87 kilometres off the coast of Yorkshire, Hornsea Project Two will have a total capacity of 1,386MW and produce enough electricity each year to meet needs of 1.3 million people. Construction is scheduled to start in 2021.

Work is already underway on Hornsea Project One, which will have a capacity of 1,218MW when it is completed in 2020.

Hornsea Project Two was one of three offshore wind farms to secure an agreement in the latest Contracts for Difference auction in September 2017. It was one of two to win a contract at a record-low strike price of £57.50/MWh – the other being the Moray East project.

At the time, Orsted cited the increasing size and therefore cost-efficiency of turbines as the main reason behind the headline-grabbing result.

Duncan Clark, programme director for Hornsea Projects One and Two, said: “We are delighted to continue our partnership with Siemens Gamesa.

“We’ve worked with them on many other UK projects, including Race Bank, which was officially inaugurated this month and the first project to use blades manufactured at the facility in Hull.”

Siemens Gamesa also provided the turbines for the London Array, which was until recently the world’s biggest offshore wind farm. The title was taken by the Walney Extension in April.

Clark MacFarlane, the managing director of the company’s UK division, said: “This latest collaboration with Orsted sees a doubling of capacity and a halving of cost per megawatt hour over London Array, installed five years ago.

“Only by using our latest technology and working closely with the customer in every aspect of the project has this been possible. Long may our collaboration continue as we help drive our industry forward.”