Planned to be constructed 13km off the Sussex coast in the English Channel, the Rampion wind farm will have an annual renewable power generation capacity of 1,333GWh.
The UK GIB is investing £236m in theproject, which features 116 3.45MW wind turbines, associated foundations, as well as an offshore substation and cabling.
E.on said that the final investment decision has been made for the project, which is planned to be commissioned in 2018.
The company will be responsible for the project construction, operations and maintenance as well as energy management services, including the delivery of the connection to the National Grid with marine export cables to shore, nearly 26km of onshore cables and onshore grid substation assets.
UK Green Investment Bank CEO Shaun Kingsbury said: "Our investment gives the developer the confidence to begin construction on this important offshore wind project, boosting UK energy supply and generating enough power annually for around 300,000 homes."
Expected to reduce greenhouse gas emissions by 4,215kt CO2e across its 25-year operational life, the wind facility will create around 300 jobs during the construction phase.
Onshore substation construction is expected to commence next month in Twineham while offshore work will begin in early2016.
