One fifth of the UK's gas is to be imported through a Kent terminal by the year 2011, the National Grid has said.
British Gas owner Centrica is among companies which will take the gas
A £310m scheme to boost capacity of the liquefied natural gas (LNG) terminal on the Isle of Grain has been given the go-ahead.
National Grid said it was in response to the UK's increasing dependence on gas supply imports.
The Grain terminal, which opened in July 2005, is already able to import 3.3 million tonnes of LNG a year.
A second phase of development is under way, with three new storage tanks being built which will treble capacity by 2008.
The third phase of building will take the figure up to 14.8 million tonnes by 2011.
Contracts have already been signed with E.On, Scottish Power owner Iberdrola and Centrica to take up the extra capacity.