22 petajoules per year is equivalent to 697 megawatts...

22 petajoules per year is equivalent to 697 megawatts (remarkably, Google calculates this for you if you input "22 petajoules per year in megawatts"). That is the theoretical maximum energy obtainable from burning the gas; modern gas fueled power stations can have an efficiency close to 50%, so let's say 22 petajoules per year can support a 300 MW plant. If this plant supplies power to customers at an average rate of 150 MW, that works out to 1.3 billion kWh per year. The retail cost of electricity in NSW is around 20c/kWh, so 1.3 billion kWh would be worth $260 million per year in revenue from retail customers.