I don't quite know what the Maquarie analyst is working with...

I don't quite know what the Maquarie analyst is working with here (been to lunch?). WCL said well over a billion, not a billion!

I think WCL's immediate target is 40 tj/d which is 40 000 gj per day X 365 = 14.6 pj per annum. WCL share = 7.44 pj

One billion over 20 years is 50 million per year. To arrive at a billion using just 7.44 pj per annum you are talking a minimum of $6.60 a gj unless I am not mistaken (which I may well be!)