Diesel stocks at 34 days: what sets Queensland's pump price

TL;DR: Australia’s diesel stocks rose to 34 days this week, but stock days aren’t in the price chain; the wholesale gate is. Brisbane diesel is 286.9 c/L at the metro median on the Queensland Government feed, 48.0 over unleaded, and 43.9 of that gap was already in the gate price on 30 October. The bigger lever is where you fill: the cheapest tenth of Brisbane diesel stations are at or under 269.9, $11.90 under the median on 70 litres.

“Outrageous – is it the same elsewhere in Australia?” — ‘oldfartinacar’, Whirlpool

That thread’s opening post pointed at diesel 29.4 cents dearer than unleaded on Western Australia’s FuelWatch metro averages for a 23 March, year unknown. Today’s Brisbane gap over unleaded is 48.0. Different state, different year, so read it for the feeling, not as a comparison. I can only measure Queensland pumps. The mechanism applies in every capital; the numbers are Brisbane’s.

The claim

On 31 October the Minister for Climate Change and Energy, Chris Bowen, said Australia’s diesel stocks were at the equivalent of 34 days of consumption, three days more than a week earlier (Xinhua). The government’s fuel plan site carries a narrower measure, reserves held under the minimum stockholding obligation, at 31 days of diesel as at 20 October (fuelplan.gov.au). The International Energy Agency’s benchmark is 90 days, but of net imports, not of consumption, so the two aren’t like for like.

It’s still an uncomfortable number to read on the way to the servo. So does a short stockpile mean my next fill gets dearer? And where does a 48-cent gap over unleaded come from?

What I checked

Daily medians for Brisbane metro (within 30 km of the CBD) and Queensland, 3 August to today. Each station’s last reported price is carried forward for up to 45 days. Diesel means the cheaper of standard and premium diesel at each station; unleaded is regular unleaded (91). The Brisbane panel today is 473 stations for diesel and 439 for unleaded. I set those against the Australian Institute of Petroleum’s Brisbane terminal gate price, the published wholesale list price, which runs to Friday 30 October.

What the data shows

The gap is wide in Brisbane and a little narrower statewide. Across 1,767 Queensland diesel stations and 1,587 unleaded in the same panel, the median is 283.9 against 239.9, a 44.0 gap. In Brisbane it is 286.9 against 238.9: 48.0. The Brisbane gap isn’t new, and it isn’t at its widest.

Monthly averages: 48.6 in August, 51.5 in September, 48.4 in October.

Most of today’s gap is wholesale. At the gate on 30 October, diesel was 269.5 and unleaded 225.6, a 43.9 gap. That leaves about 4 cents of today’s 48.0 sitting between the gates and the bowsers. The other 43.9 was there before any servo set a price.

In three weeks that split went from about half wholesale to nine-tenths. In my 11 October post the pump gap was 49.0 and the gate gap 23.6, so about half of diesel’s extra sat between the gate and the pump. The pump gap has barely moved since. What moved is unleaded wholesale: the unleaded gate fell from 241.6 on 9 October to 225.6 on 30 October, 16.0 cents, while the unleaded pump median went from 239.9 on 9 October to 238.9 today. The diesel gate rose 4.3 over the same dates. Unleaded has gone from 1.7 under its gate to 13.3 over it. Both posts are right for their week.

The chain is the same wherever you fill up in Australia: a world diesel price, the dollar, your terminal’s gate price, then the pump, on a lag. The gate is set off refined diesel in Singapore, not Brent crude, and trails it by a few days. Brent’s front month settled at US$113.43 on 30 October after limpet mines hit a tanker in the Strait of Hormuz (CNBC); that’s a different contract from the US$116.72 in my 25 October post, not a fall from it. The Brisbane diesel gate rose 2.6 cents over October, from 266.9 on 1 October to 269.5. Whatever Singapore diesel did on Friday isn’t in it: Friday’s gate was collated that morning, before Brent settled, and fell 0.7.

The pump took less than half of October’s gate rise. From October’s low gate price, 263.9 on 15 October, to 30 October, the gate rose 5.6 cents and the pump median rose 2.6, from 284.9 to 287.5. More than half of the gate’s rise came in the last five trading days, which matters for the lag. My July post on the lag measured a 13.8-day half-life. When I re-ran it on 18 October, different windows gave anywhere from 8.7 to 30.3 days. Applied to the gate’s day-by-day path from 15 October, that range puts about 0.8 to 2.3 cents at the pump by 30 October. The pump’s 2.6 is just above the top of that range, by 0.3, within the half-cent steps the median moves in. Start a day earlier and the answer changes: the gate was also 263.9 on 14 October, and from there the pump rose only 0.6. The July post also found that over two weeks, rises passed through roughly 0% while falls passed through about 56%, on a thin sample. One episode doesn’t overturn either finding.

My 18 October forecast, graded. I put the pump somewhere between about 285 and 289 by early November, if the gate took the full 3.9. It took a bit more, 4.7, from 264.8 on 16 October to 269.5 on 30 October. The pump is at 286.9, inside the range. It was a wide range, and the gap assumption didn’t hold: it narrowed to 17.4, so the number landed in range partly for the wrong reason. A pass, not proof.

The pump’s gap over the gate is under all three published yardsticks. Today’s 286.9 sits 17.4 over the 30 October gate. Like for like on 30 October it was 18.0 (287.5 against 269.5), down from 21.0 on 15 October and below the 19.6 my 25 October post called October’s narrowest. Against the three yardsticks from my 11 October post, today’s 17.4 is 5.3 under the 22.7 long-run figure from the July lag post, 3.1 under the 20.5 median since January 2024, and 3.0 under the rolling 30-day median, which re-runs as 20.4 for the 30 days to 1 November (it was 19.0 on 11 October and 21.0 for the 30 days to 16 October).

The verdict

The stock figure measures how long the country could keep going if supply stopped. That’s a security question: it bears on whether there’s diesel at the bowser if shipments are interrupted, which matters if your ute is how you earn. It doesn’t set what diesel costs at the gate. The Brisbane gate is set off refined diesel in Singapore, and a few more days in Australian tanks don’t change what a cargo costs there. This week’s numbers don’t contradict that. Stocks rose three days, and the Brisbane diesel median went from 285.9 to 286.9, in step with its gate rather than against it.

If the gate held at 269.5 and the pump’s gap over it went back to its usual level on those three yardsticks, there would be room for the pump to rise 3.0 to 5.3 cents. That would be a rise at the bowser, not a cut. Half of it, the July curve’s middle reading at two weeks, is about 1.5 to 2.7. That’s arithmetic on yardsticks, not a forecast, and the gate probably won’t hold: if Singapore diesel followed Brent up on Friday, that hasn’t reached the gate yet. Monday 2 November’s file is the earliest that could show it, Tuesday’s more likely.

What it means for your fill

• The spread beats the drift. In the same 473-station panel as the median, the cheapest tenth are at or under 269.9: 17.0 under the median, $11.90 on 70 litres. The whole 3.0 to 5.3 yardstick range is $2.10 to $3.71 on 70 litres.
• The cheap end. The cheapest diesel reported in the past 72 hours is 261.5, at Ampol Foodary Waterford West, reported 7.07am Friday 30 October. That’s 25.4 under the median: $17.78 on 70 litres. Over the past week it’s 259.5 at 24Xpress Marsden Park (Marsden, Logan), reported 1.26pm Wednesday 28 October: 27.4 under the median, $19.18 on 70 litres. Both are 8 to 10 cents under Friday’s published gate price of 269.5. The gate is a list price and some sites buy under it, so a pump price below it isn’t by itself evidence of a loss or a bad reading. Check before you drive.
• The dear end, same rule. The dearest diesel reported in the past 72 hours is 298.9, at Ampol Eagle Farm (3.37am Saturday 31 October), Ampol Foodary Hamilton (3.32am Saturday 31 October) and 7-Eleven Ascot (6.25am Friday 30 October). That’s 12.0 over the median: $8.40 on 70 litres. Over the past week it’s 299.9, at Ampol Foodary Toowong, EG Ampol Mount Ommaney, 7-Eleven Jindalee and Ampol Foodary Jindalee, last reported Tuesday 27 October: $9.10 over the median on 70 litres. Check before you drive.
• End to end, the 72-hour cheapest and dearest are 37.4 apart: $26.18 on 70 litres, about seven times the top of the yardstick range.

Pick All Diesel on fill.pinly.com.au and you’ll see the same series as this post, the cheaper of standard and premium at each station, and every price is the one the station itself reported to the Queensland Government feed.

Honest limits:

• Scope. Pump figures are Queensland only. Brisbane is within 30 km of the CBD. 1 November is a part day, pulled at 5.06pm AEST, and medians can move a few tenths by midnight. The latest gate price is Friday 30 October; AIP doesn’t publish on weekends, and regional Queensland is supplied from terminals AIP doesn’t publish.
• The panel. Each station’s last reported price is carried forward if it was reported within the 45 days up to the end of that day, and the median is taken across stations. Diesel is the cheapest of standard and premium diesel per station. The statewide 1,767 diesel and 1,587 unleaded are counted on the same rules as Brisbane’s 473 and 439, and are Queensland stations only. The 473 includes three Shell Reddy Express sites showing a 999.9 placeholder and marked unavailable. Across the 470 marked available, the median is still 286.9 and the cheapest tenth still 269.9.
• The cheapest tenth. The 269.9 comes from the 45-day carry-forward panel, which keeps prices the ends section leaves out as stale, such as three sites at 261.5 last reported 22 October. Limited to stations that reported in the past seven days (423), the cheapest tenth is still 269.9; in the past 72 hours (244), it’s 270.2.
• The gap over the gate, and how fast it closes. The 17.4 is today’s pump median against Friday’s gate; the 18.0 is both on 30 October. The 22.7 is the 18-month median from the July lag post (my 11 October post found it re-runs as 22.2 on this panel), and the 20.5 is the median since January 2024 from that post. The 30-day median is re-run for this post over 3 October to 1 November, with weekends counted at Friday’s gate; to 30 October it is 20.75. I don’t use August or September as a yardstick: August carries the 1 August excise step (on 3 August the pump sat 1.5 under the gate, 245.5 against 247.0), and September’s gap was squeezed, to 12.5 on 9 September, as my 11 October post found. None of these is a profit figure. Each holds freight, retailer costs and margin together, and I can’t separate them. The 13.8-day half-life is from the July post, on data to 23 July; the 8.7 to 30.3 range is from my 18 October re-runs over three windows, not re-estimated since. The 0.8 to 2.3 applies each half-life to the gate’s daily changes from 15 to 30 October only. It leaves out any pull from the gap itself: on 15 October the pump sat 21.0 over the gate, under the 22.7 or 22.2 long-run figure, and that pull would raise the fast end.
• The start day. The pass-through result depends on where you start. The gate was 263.9 on both 14 and 15 October. From 15 October the pump rose 2.6 (284.9 to 287.5); from 14 October, at the same gate price, it rose only 0.6 (286.9 to 287.5), below the 0.8 to 2.3 range. From 13 October the pump was flat at 287.5 while the gate rose 4.7. The 0% and 56% for rises and falls are from the July post and rest on 66 to 103 events a side. The pump median moves in steps of half a cent or more, so one episode is a weak test.
• Under the gate. 261.5 and 259.5 are 8.0 and 10.0 under Friday’s 269.5 gate. The gate is a published list price. AIP cites an ACCC analysis that found what customers paid differed from the gate by 0.7 c/L on average in 2013–14, through volume discounts for contracted buyers and large orders, so 8 to 10 under is well past that average. I have no data on what any site paid, so I can’t say whether either price is a loss. On 11 October no Brisbane metro station reporting diesel as available was under the gate; this week, some are.
• External figures. The 34 days, “days of consumption” and the week-earlier comparison are Bowen’s, as reported by Xinhua on 31 October. The 31 days is fuelplan.gov.au’s “national days of coverage based on normal rates of consumption” under the minimum stockholding obligation, as at 20 October. The IEA’s 90 days is measured against net imports. Nothing in our data links stock days to price; the verdict rests on how the gate is priced, and this week’s figures only fail to contradict it. Brent’s settles and the tanker attack are from CNBC, 30 October. The US$113.43 is the January contract, up US$2.63 on the day. The US$116.72 in my 25 October post was the December contract, which expired the same Friday at US$117.64, and January took over as the front month. I don’t quote a monthly Brent change: the sources I found disagree on the September starting point.
• Grades. Unleaded is regular unleaded (91, ULP). Diesel is the cheaper of standard and premium diesel at each station.
• The gap. The diesel-minus-unleaded gap moves with unleaded as well as diesel. The monthly averages are means over every day, August from the 3rd. This post makes no claim about the petrol cycle.
• The ends. Live prices pulled at 5.06pm AEST on Sunday 1 November. Both ends use the same rules: reported in the past 72 hours (since 5.06pm Thursday 29 October), then the past seven days (since 5.06pm Sunday 25 October). Stations last reported before that are left out at both ends: BP Milton at 299.9 (last reported 8 October), and Pearl Energy Manly West, Pearl Energy Cannon Hill and Shell Tingalpa at 261.5 (22 October). A 321.5 quote at a marina site is excluded as likely marine diesel, and the 999.9 placeholders are excluded. A station reports only when its price changes, so an older timestamp isn’t necessarily a wrong price, but check before you drive. Dollar figures are the c/L gap times 70 litres; on 100 litres the cheapest-tenth saving is $17.00.
• The quote. The Whirlpool line is from the “Diesel price gouging” thread, recorded with the username only. As in my 7 October post, the 29.4 comes from the thread’s opening post, which cited WA FuelWatch metro averages for a Monday 23 March (diesel 140.2, unleaded 110.8), year unknown; it’s an average, not what anyone paid. It’s about the diesel premium in general, not this week or the stock figure.

— Tom