The new power plant will replace the company’s 1,200MW Cockenzie coal-fired power station on the site.
The existing coal-fired plant, which commenced operation in 1967, is set to close by the end of 2015.
The new power station will be carbon capture ready and will be required to fit full carbon capture and storage technology once it is commercially and technically proven.
The Scottish government said natural gas is a much more efficient fuel than coal and will more than halve carbon and nitrogen dioxide emissions compared to the existing power station.
The government has also approved a separate application for a 17.5km pipeline from the existing gas network at East Fortune to the new power station.
