The Fuel Rule Being Written Right Now Could Change Your Diesel

There's a Commonwealth consultation paper sitting on a government website that closes on 15 September, and outside a few dozen people in the fuel and freight industries, almost nobody has read it. That's a shame. Because whatever comes out the other side of it will eventually turn up in the tank of every diesel ute, truck and tractor in the country.

Here's what's really going on.

Canberra just switched which end of the pipe it's pushing on

On 18 August the federal government opened consultation on what it calls a demand side measure for low carbon liquid fuels. Submissions close on 15 September 2026. The language is dry enough to put you to sleep, but strip it back and the question is blunt: should Australia legally require fuel suppliers to put a certain amount of renewable fuel into the national fuel pool?

Two mechanisms are on the table. The first is a volumetric mandate, which is exactly what it sounds like: a fixed blending requirement or a market wide volume target. The consultation paper floats the possibility of obligated suppliers replacing up to 20 per cent of their total fuel supply with low carbon liquid fuels. The second is a carbon intensity standard, which sets a target for the average emissions intensity of fuel sold and lets suppliers work out their own path to hitting it, including through credits.

That's a genuine fork in the road, and it matters more than the wording suggests. A blending mandate tells industry what to pour. A carbon intensity standard tells industry what outcome to hit and leaves the how alone.

Why now? Because the government has already spent the money on the supply side and worked out that money alone doesn't build refineries. The $1.1 billion Cleaner Fuels Program, announced in September 2025, offers production linked incentives over ten years. ARENA was named as the delivery agency in May 2026 and is still writing the program guidelines, with the first application round due in the 2026 to 2027 financial year. Producers, quite reasonably, have been saying the same thing to Canberra for two years: we're not signing off on a plant unless somebody is contractually obliged to buy what comes out of it.

What renewable diesel actually is, because most people get this wrong

This is the bit worth understanding, and it's where the story gets interesting.

Renewable diesel is not biodiesel. Biodiesel is the stuff with the reputation, the fuel that gels up in the cold, chews through rubber seals in older engines and comes with blend limits printed on the bowser. Renewable diesel is a different beast entirely. It's made by hydrotreating fats and oils, and the molecules that come out the other end are chemically indistinguishable from the diesel refined out of crude oil.

Queensland's Deputy Premier put it about as plainly as anyone could earlier this year: the chemical compound of renewable diesel is exactly the same chemical compound as normal diesel. No engine modification. No warranty conversation with your mechanic. No new bowser. You could be running it now and not know.

The feedstock is the surprising part. Tallow from abattoirs. Used cooking oil from fish and chip shops. Canola oil from paddocks in the Riverina and the Wimmera. That's the supply chain, and it's why the biggest player in this isn't an oil major at all. GrainCorp is a grain handler.

The Lytton experiment

The most advanced project in the country sits on the bayside in Brisbane. Ampol's Lytton refinery, one of only two operating refineries left in Australia, is being modified so its existing diesel hydrotreater can co process conventional feedstock alongside waste oils and animal fats.

The Queensland government tipped in $25 million in April 2026 with fast tracked approvals attached. Stage one targets up to 20 million litres a year, with construction starting by mid 2027 and production by 2028. Stage two, if it happens, aims at more than 750 million litres annually by the early 2030s, including sustainable aviation fuel.

To feed that, GrainCorp has been assessing a greenfield oilseed crush facility of up to a million tonnes a year. Ampol, GrainCorp and IFM Investors have been working the value chain together since 2024. Over in Western Australia, BP has its own biorefinery ambitions at Kwinana.

Twenty million litres, to put this in perspective, is not very much. Australia burns through roughly that volume of diesel in a couple of hours. Stage one is a demonstration, not a supply solution. Whether stage two happens depends almost entirely on whether the consultation that closes on 15 September produces something with teeth.

We've done a fuel mandate before, and it went sideways

Here's the fascinating backstory most people have forgotten.

New South Wales legislated an ethanol mandate more than fifteen years ago, requiring that a set percentage of total petrol volume sold in the state be ethanol. The target was never consistently met. Retailers found it easier to wear the compliance friction than to rebuild their forecourts, motorists remained sceptical about E10 prices and what the fuel would do to their engines, and the whole thing became a case study in what happens when you mandate a product the public hasn't been sold on.

Renewable diesel dodges that particular trap. There's no consumer education problem when the molecule is identical and nothing on the bowser changes. The problem this time is purely economic: renewable diesel currently costs more to make than crude oil diesel, and somebody has to carry that gap.

Internationally, we're arriving late. California has run a carbon intensity standard on transport fuels since 2011 and it has reshaped diesel supply on the American west coast. Europe has mandated renewable content in transport fuel for years. Brazil has been blending ethanol into its petrol since the 1970s. Australia has spent that time importing about 90 per cent of its refined fuel and hoping the shipping lanes stay open.

The practical upshot for your wallet

Let's be honest about the mechanics. If suppliers are legally obliged to buy a fuel that costs more than the one they're currently buying, that cost lands somewhere, and historically it lands on the pump price.

A few things worth keeping in mind, though.

Diesel carries the exposure, not petrol. Renewable diesel and aviation fuel are where the technology and the feedstock actually work, so if you're watching diesel prices you're watching the fuel most likely to move. Unleaded is comparatively insulated in the near term.

The pass through would be diluted. A 20 per cent blend obligation means 20 per cent of the volume carries the premium, not all of it. Whatever the number ends up being, it gets averaged across the whole pool before it reaches you.

And none of this touches your bowser price in 2026 or 2027. The consultation closes this month, design work follows, legislation follows that, and the first meaningful volumes are 2028 at the earliest. Anyone telling you your diesel goes up next month because of a biofuels policy is selling something.

The genuine upside is the one nobody puts on a price board. Fuel made from Australian canola and Australian tallow in an Australian refinery is fuel that doesn't sit on a tanker for three weeks. That's worth something the day a shipping lane closes, even if it never shows up as a cent per litre saving.

What to take away

The fuel industry rarely makes headlines until prices spike, but the rules being drafted this month will shape what's in your tank for the next decade. Worth paying attention now, while it's still a consultation paper and not a bill.