I heard an interview with the EPA yesterday. The main concern is that Chevron want to build the terminal offshore on Barrow Island. This is a unique nature reserve which doesn't have the introduced species which have wiped out many native species on the mainland. The EPA don't think quarantine could be maintained with the large workforce required for the LNG plant travelling back and forth.

EPA want them to build the LNG terminal on the mainland. There is also some interest from politicians in possible encouraging gas-to-liquids down the track and there may ultimately be a pipeline for domestic consumption in the east but this is not likely in the short term. Coal-bed methane in the eastern states is more likely to be developed first, and the price for gas in the eastern states (currently cheap) doesn't offer muchy incentive for a pipeline from WA.

I think the gas pipeline from Papua New Guinea will probably supply the east coast with gas for quite a while - coal seam methane will kick in a bit later.

Either way a pipeline from WA seems highly unlikely - I would expect (and hope) that they just put an LNG plant on the mainland and leave Barrow island alone...