Australia s North West Shelf LNG project needs more gas. Its supply fields are entering decline and liquefaction capacity will be available from 2021. The NWS joint venture is looking to toll third party gas through the existing liquefaction infrastructure and has recently proposed non binding key terms. The NWS backfill schedule neatly aligns with an expected shift from an oversupplied to an undersupplied LNG market in 2023/4. Wood Mackenzie believes there are options available that are cost competitive with most pre FID projects globally. However the lack of equity alignment between the phases will be a significant hurdle. Agreement within the NWS joint venture on tariff structures and levels may also be difficult. Wood Mackenzie believes a tolling tariff below US$2.50/mmbtu but above US$1.00/mmbtu will be needed for a project to be economically resilient. An alternative to tolling would be an integrated development but risk sharing through unitisation would involve complex M&A.