The UK energy company is to buy around 1.75 million metric tonnes a year from Cheniere Energy Partners over a 20 year period, enough to supply around 1.8 million homes. The first delivery is due in September 2018.
The price will be indexed to the “Henry Hub” natural gas price.
Sam Laidlaw, chief executive of Centrica, said: “In an increasingly global gas market, this landmark agreement represents a significant step forward in our strategy, enabling Centrica to strengthen its position along the gas value chain and helping to ensure the UK’s future energy security.”
Prime minister David Cameron and environment secretary Ed Davey also welcomed the agreement, saying gas supplies from America would help diversify the energy mix.