Ann: DEL Enters Landmark Collaboration Agreement with Brickworks, page-87

IRR is for the Yarra Valley or the plant owner. If you look at the DEL's report than Stanhope VIC has IRR of 14.44% approx. DEL has nothing to do with Stanhope IRR. But if the price of electricity rise than Stanhope will further benefit not DEL. So there will be more incentive to own a plant as price of electricity and gas rise.
However, DEL has past experience in these kind of plants. Joe was based in UK and was involved in such plant construction. There are $500 million worth of 22 projects. Even if they miss out on profit on one or two that will not change anything but at the same time hope they acquire more FIDs for newer projects.