Siemens AG has signed an agreement to supply up to 500 offshore wind turbines to Dong Energy for wind farm projects in northern Europe.

The wind turbines to be delivered under the supply agreement have total capacity of up to 1,800 megawatts.

René Umlauft, CEO of the Renewable Energy Division of Siemens Energy, said this agreement is one of the biggest orders in the history of Siemens.

Though financial details weren’t shared, it has been reported that the Danish company, which had a record revenue of more than 60 billion kroner last year, has signed a deal worth 20 billion kroner with the German producer.

The wind turbines which Siemens will deliver under the supply agreement have a capacity of 3.6 megawatts similar to the turbines in operation at Dong Energy’s Burbo Banks offshore wind farm and those being installed at Gunfleet Sands I+II project.

The two companies, which together constructed the world’s first offshore wind farm at Vindeby in Denmark, have strengthenged their relationship. The two have also worked on other offshore projects including Middelgrunden near Copenhagen (Denmark), Nysted in Southern Denmark, Burbo Bank in Liverpool Bay (UK) and the soon to be installed Gunfleet Sands I+II (UK) and Horns Rev 2 (Denmark).