China’s soaring energy demand has forced it back into the global natural gas market in search of cleaner burning though potentially more expensive fuels to power industry and provide residential electricity. Hu Jintao, China’s president, presided over the signing of a 20-year agreement between PetroChina and Royal Dutch Shell in Perth on Tuesday for liquefied natural gas from the Gorgon project off Western Australia.

China signed its first-ever long-term LNG supply deal five years ago, also with Australia, but had baulked at paying the higher world prices which have prevailed in most markets since then.