ScottishPower aims to build the plant near Hoo St Werburg and create more than 1,000 jobs during construction.
Energy minister Charles Hendry said the plant would be built “carbon capture ready” so that eventually CO2 from the site could be stored under the North Sea.
He said the plant would sit along the existing power station and be known as Damhead Creek 2. It will generate enough electricity to power 1.5m homes and secure electricity supplies for the South East.
ScottishPower commercial development director Roger Seshan said: “This is a major achievement and an important milestone for the proposed project.
“Our immediate plans will see further development work carried out at the site in the coming months.
“This will fully establish our plans for the site and determine the future timetable for the project.”
ScottishPower said that its proposed new plant would emit about half the amount of CO2 of an equivalent sized coal-fired power station.
The new power station has been designed so that carbon capture technology can be added easily when the technology is proven.