"A second GTG is now operational and producing power for use on the site, a critical step toward production of LNG," Bechtel said.

Each GTG is designed to produce around 12 megawatts of electricity, enough to power 11,000 homes, with six of them to satisfy the total power needs of the project's two-train, 7.8 million tonnes per annum capacity LNG plant.

"Our recent milestones - bringing first gas onto site, lighting the flare and firing the first GTGs - are key steps to producing our first LNG on the project and are the result of a lot of hard work from our team and a great level of coordination with our customer, Santos GLNG," Bechtel's global LNG general manager Alasdair Cathcart said.

"2015 is a critical year for our Curtis Island construction projects with all three sites producing LNG, including startup of Queensland Curtis LNG's second train."

Macquarie Wealth Management previously forecasted first LNG from the project to occur late in the September quarter.