I interpret the assertion that the project’s input NG is “free” to mean that the taxes and fees that would be levied on commercial NG are not applied. The opportunity cost of the consumed gas is real, however, as you pointed out.
Don't agree at all that GTL is a dead end.
Now I have a dilemma… should I believe you, or should I believe XOM? :- )
“The efficient-market hypothesis may be the foremost piece of B.S. ever promulgated in any area of human knowledge!”