US liquefied natural gas exporter Cheniere Energy may be looking at expanding its LNG export facility at Corpus Christi, Texas, beyond the third stage it sanctioned last month.

The possibility was revealed on Wednesday as the company announced it had reached a long-term sale and purchase agreement with a subsidiary of PetroChina.

The PetroChina agreement calls for Cheniere to supply as much as 1.8 million tonnes per annum of LNG, with deliveries set to begin in 2026 and run through 2050 — a span of 24 years in an industry where longer contracts usually last 20 years.