The two companies will now become equal joint partners in the project, which, when built in the outer Thames Estuary, could generate enough power to supply a quarter of Greater London homes.
Dr Paul Golby, chief executive of E.ON UK, said: ‘We’re pleased that, together with DONG Energy, we’ve been able to secure the future of the project.
‘We hope to be able to keep the project on track and we should be able to complete the first phase by the end of 2012, subject to securing a number of important contracts, such as those for the wind turbines.’
Mike Lewis, managing director Europe of E.ON Climate & Renewables, said: ‘While the economics of this project remain challenging, we believe this flagship project will give us invaluable experience as we go forward with the next generation of offshore projects.
‘That means that we can take the lessons we learn from London Array for future projects that are further offshore and, potentially, even larger.’
E.ON Climate & Renewables already operates a 60MW offshore wind farm in UK waters - Scroby Sands off Great Yarmouth - and is currently building a 180MW scheme - Robin Rigg in the Solway Firth. It has also applied for planning permission to build the 300MW Humber Gateway offshore wind farm.
E.ON claims it has a renewable development portfolio in the UK that could produce enough renewable power for around a million homes and displace the emission of almost two million tonnes of carbon dioxide a year. Worldwide, the group plans to invest €6bn (£4.8bn) in renewable energy projects by 2010.