Increased production - Sales to Alcoa "Additional gas produced...

Increased production - Sales to Alcoa

"Additional gas produced will be sold to Alcoa of Australia Limited (Alcoa), Western Australia’s largest gas customer, under existing arrangements."
Relating to Alcoa's nomination arrangement (who and how much they purchase from each supplier each period)

Interruptible meaning "spot sales". If someone else comes along with a better price from time-to-time, EGO will sell Alcoa's extra nomination to the spot purchaser. But this will not affect the existing arrangements with Alcoa (probably no skin off their nose).