The snowball

From a snowball to an avalanche#

Add up every project’s unused, uplifted deductions and you get the industry’s deduction pool. In 1999–2000 it was $2.4 billion. By 2017–18 it had reached $336 billion. In 2024–25 it was still $280 billion.

That is nearly seven years of all the revenue the PRRT counts, carried forward and waiting to cancel tax.

What made it grow#

• Giant projects. The LNG boom brought projects costing tens of billions each. Every dollar spent became a deduction.
• Compounding uplift. Unused deductions grow every year, so a big pile grows by billions on its own, even if nothing new is spent.
• Bringing more projects in. In 2012 the PRRT was extended to the North West Shelf and onshore projects, and their deductions joined the pool: the jump you can see in the chart. Onshore projects were taken out again from 1 July 2019.

Why it matters#

As long as a project’s pile of deductions is bigger than its revenue, it pays no PRRT, however much gas it sells. Picture a snowball rolling downhill: the bigger it gets, the faster it grows, and the longer before it ever stops. Until 2023, nothing in the rules made it stop.