Tenders will now be invited to install the 341 turbines for the 1,000MW London Array offshore between Clacton-on-Sea and Margate.
The scheme won planning permission almost a year ago. In September, the government backed a controversial substation at Cleve Hill in Kent after Swale Borough Council had refused it.
A spokesman for E.ON, which is developing the project with Shell WindEnergy and DONG Energy, said work is still set to begin in 2009.
Energy minister Malcolm Wicks has also approved a wind farm of up to 152 turbines near Walney Island off the coast of Cumbria. DONG is behind the scheme, which could generate electricity for about 360,000 homes.