Update on Sydney Petrol Prices

by Stubborn Mule on 21 July 2008 · 13 comments

A little while ago I wrote about the relationship between crude oil prices and the price Sydney motorists are paying for petrol at the pump. The Australian Automobile Association (AAA) has now released their price data for June and, not surprisingly, prices continued to track moves implied by rising crude oil prices. The simple regression model suggested that average prices would be up 8 cents/litre. The AAA data shows a rise of 10 cents/litre in the average Sydney price.

Sydney Petrol Price Model (Brent Crude)

What is also evident in this chart is the rapid fall in crude oil prices over the last week. One explanation for this fall was an unexpected rise in US inventories. Other commentators have pointed to a self-correction mechanism with higher prices leading to changes in consumer behaviour which are anticipated to be reducing demand. These developments should mean that Sydney drivers will see prices stabilising after several months of steep price rises. That is, of course, unless the price falls are short-lived.

My original post was syndicated on the Oil Drum, where it has attracted a number of comments. One commenter, Anawhata, mentioned comparisons with Tapis (Asia) crude oil prices as opposed to Brent (Europe/Africa) prices. I chose Brent because it is the most widely quoted in our media, but using Tapis prices in the regression does give a very slight improvement to the model (R2 is 97% rather than 96%), For completeness, here is the chart for the Tapis model, although it is hard to see much of a difference.

Sydney Petrol Price Model (Tapis Crude)

Of course, an even better model can be obtained by using refined rather than crude oil prices. The chart below shows the result of modelling Sydney petrol prices in terms of Singapore 97 Octane gasoline (the R2 is 98%)

Sydney Petrol Price Model (Singapore 97)

UPDATE: Maybe I spoke too soon about crude oil prices! The lastest news is that a tropical storm heading towards Mexico and more difficulties with Iran on the nuclear question have started pushing prices up again.

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{ 12 comments… read them below or add one }

1 Duncan July 22, 2008 at 3:51 pm

Prawny -

On the radio this morning someone (it was too early to remember the name) mentioned that the recent crude oil price drop would take 7-14 days to filter through to the pumps due to storage tanks, current supplies etc etc. In contrast, my impression is that the lag between crude oil price increases and Sydney petrol price increases would be better measured with a stop watch than a calendar.

Is there enough sensitivity in the data to measure the time differences (if any) of your correlation with respect to the price trend (upwards or downwards) ?

2 stubbornmule July 22, 2008 at 4:04 pm

Unfortunately the data I have for petrol prices consists of monthly averages (from AAA), which is too coarse to measure time lags over 7-14 days. The crude oil (and Singapore refined data) is daily, so if only I could find daily retail petrol price data…

3 Duncan July 22, 2008 at 4:07 pm

Has anyone averaged the Perth prices from their FuelWatch scheme ?

4 Mark L July 22, 2008 at 9:51 pm

Daily historical petrol price data is sold by, for example, Informed Sources:

Of course, if you are patient and persistent enough, you can harvest it yourself each day from, for example:

5 stubbornmule July 23, 2008 at 10:05 am

Interesting to see that the NRMA is calling for petrol prices to be down to $1.35 based on falls in Singapore prices. Economists are saying the fall will not be as large as that. As you can see from the Singapore chart above, I’m with the economists: Singapore price falls would seem to point to prices around $1.50 not $1.35.

6 stubbornmule July 23, 2008 at 10:34 am

@Mark L: thanks to the pointers to the data. Now to work out how to automate harvesting that Shell data!

@Duncan: In 2007, The ACCC published a report on Australian Petrol Prices which included an analysis of Perth’s FuelWatch:

“This included an econometric analysis indicating some reduction in relative pricing margins between Perth and the eastern capitals in the time following FuelWatch’s introduction”

The econometric analysis was released in May 2008 and concluded:

“From the econometric analysis, on a conservative basis, the ACCC can say that there is no evidence that the introduction of Fuelwatch in Western Australia led to any increase in prices and it appears to have resulted in a small price decrease overall.”

This report also includes the fall in weekly average prices of 1.9 cents/litre which has been bandied about widely (e.g. here). However, the report itself notes that FuelWatch may not be the only factor at play. For example, they note “the entry of Coles into Perth was an event that may have had a price impact”

Overall, reading the ACCC documents these are fairly meek conclusions, and furthermore, a draft paper by a La Trobe econometrician discussed over on the Possum Pollytics blog suggests that there are weaknesses in the ACCC methodology. The paper argues that even their weak conclusions are hard to support using the price data.

7 John Angelico September 18, 2008 at 11:15 pm

Hi from Melbourne.

I work in the retail end of the oil industry supplying industrial and commercial lubricants and greases.

There are many wild statements made in the press about the putative links between movements in crude oil prices and bowser prices for fuel, usually to attack the oil companies for “ripping off” us poor car owners.

Duncan’s question is quite pertinent but the timing goes (very) roughly like this:

1. Today’s media reports a spot price for forward delivery in approx 30 days, so
if a deal is struck today, the refinery feedstock price will apply in about a month’s time
2. It takes about 3 weeks roughly for feedstock prices to influence output prices through the refining process (please don’t open the tin of worms which is refinery cost accounting)
3. It takes about a week to ship refined fuel from Singapore to Australia
4. Allow a week or two for storage and distribution within Australia

Thus the comparison of crude prices reported in the press to bowser prices should involve a lag of roughly 8-9 weeks.

Therefore the prices we see at the bowser (or better yet the terminal gate prices) should be compared with the crude oil price of 8-9 weeks ago. For today 19th Sep that means crude prices ruling about late July.

Consequently, we are past the worst of the speculative peak, and should expect further drops in the bowser price to come – maybe a nice Chrissy present…

None of this reflects exchange rate movements, which most people forget, nor does it represent the actual mechanics of the Import Parity Pricing process, which may work off the Singapore Unleaded Price (MOPS95) and therefore reflect about a three weeks lag. Since I am way down at the tail end of the other side, I don’t know that part of the industry.


8 stubbornmule September 19, 2008 at 9:28 am

@John: thanks for your comment, it makes a lot of sense. Even in my data, which doesn’t allow for the time lag and only represents monthly averages, it is clear to me that wholesale prices are feeding directly to retail without the profiteering some people seem to claim. So it is good to hear a more detailed explanation of how the process actually works.

9 Amir Ashrafi October 28, 2008 at 2:24 pm

Today 28th October 2008, 1AUD = 0.61USD and one barrel of oil = USD$61 therefore: 1 barrel of oil is exactly AUD$100

Back in July 08, @ 1AUD=0.98USD; one litre of petrol was AUD1.60 as an avg of Sydney prices (it peaked to 173.9cents/L for unleaded) one barrel of oil was USD$147

The ratio of cost of a barrel of oil to a litre of petrol in July 2008 was USD147/AUD1.6 or in AUD terms AUD$150/1.60 (exchange rate was 0.98US to the dollar) this ratio comes out to 93.75

therefore if you divide the cost of barrel of oil in AUD by this ratio, you should get the price of petrol at today’s rate?

therefore: $100/93.75 = $1.07

So someone please tell me why the $%#^%$# am i paying $1.42/L at the pumps today?!?!?!

I could be saving 35cents a litre which works out to about $20 per week in savings for me and the average vehicle, which I could be using to payoff my good time habits or mortgage as the case may be.

According to Australian Bureau of Statistics in 2003 there were 10.4 million registered vehicles in Australia. Say 11 million in 2008. 11,000,000 X $20 = $200 million per week. This is how much money we are paying the oil companies at the moment over and above the market rates which prevailed at the height of the oil boom in July 2008.

What a nice little earner. How much longer will it continue???

Petrol companies claim it is the weak aussie$ that makes it so if that was the case, the AUD would have to be less than 50cents US for this to be true.

10 Amir Ashrafi October 28, 2008 at 2:41 pm

For Messrs Stubbornmule and John Angelico,

Peak oil prie was USD$147 on the 11th of July.

Peak fuel price in Sydney was on the 10th of July at 173.9c/L

Can you please explain this paradox?

11 John Angelico October 28, 2008 at 3:11 pm


If you check http://www.aip.com.au/pricing/marketwatch.htm you will be able to follow the movements. There are other pages on the AIP site worth looking at as well.

As I said, I do not carry a flag for the oil companies, but I want the discussion to be open and transparent.

AND as I said, the Import Parity Pricing scheme sets a Terminal Gate Price based on Singapore prices of Unleaded Fuel and 50ppm Diesel converted to AUD, not directly on the USD price of crude.

So, your example skates over a few factors, one of which is the highly volatile exchange rate. The AU/US rate is now hovering around a disastrous 60c, having lost around 35% of it’s “value” since the peak you indicated. On normal trade flows, I estimate the AUD/USD rate should be in the 75-85c range.

Some in the news have estimated that bowser prices are overstated by around 3c/ltr. My rough estimate is in the 5-8c/ltr range. Both of these estimates are within the scope of “marketing support” or retail discounts, so my thinking is that the oil companies have simply stopped heavy discounting in metro areas.

We may not like it but we can at least keep a better eye on things personally than a government website can… :-)

12 stubbornmule October 28, 2008 at 4:05 pm

@Amir: thanks for the query. I don’t know if you’ve seen the most recent post on this subject, but it shows that Sydney petrol prices are falling in line with the A$ wholesale price. Also, if you are paying 147c/L it might be worth shopping around a bit. On the AAA website they publish the daily FuelTRAC best price around Australia’s capital cities. Today Sydney is showing 129.9c/L. I bought some petrol yesterday and found that simply picking a service station off the main road saved me almost 4c/L.

But to get to the key issue in your “paradox”, the important thing to realise is that you cannot look at the ratio of price terms because this ignores the margin, which is largely independent of the wholesale price. For Australian petrol prices, the excise alone is a bit over 38c/L. To see why the margin makes a difference. Consider a hypothetical example in which the price of petrol was 50c/L plus the whole price of refined petroleum. Assume that the 50c/L margin (covering excise, transport costs, retailer profit, etc) does not change with the wholesale price. Now let’s say that the wholeale price is 100c/L but then it falls by 50% to 50c/L. In this scenario, the retail petrol price starts at 150c/L and then falls to 100c/L which is only a 33% fall! So here there is no profiteering, no manipulation of prices and yet the retail price does not fall as much as the wholesale price.

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