fuel costs in Australia - petrol, diesel

see also:

• photography and camping main index page
• 12V batteries, EV cars and camping

• Australia has a Federal Govt fuel excise which is a flat sales tax levied by the Australian Government on petrol and diesel bought at the bowser.
  • the current rate is 52.6 cents in excise for every litre of fuel purchased.
• the wholesale terminal price adds ~33c/L for wholesale and distributive costs
• 70% of service stations are privately owned
• in general, petrol stations can charge 15c/L higher than the wholesale (terminal gate) price (which includes the fuel excise) however, the petrol chains usually have a regular and fairly predictable recurring cycle of price increases to improve their profit margins - these approximately monthly cycles (sometimes sharp weekly cycles) are general led by increases in a different chain each cycle and the other chains then follow suit - being the highest price will lead to less sales so each chain takes it in turn
• retail prices usually lag wholesale ones by several days at least and usually lag global oil price changes by about 2 weeks (unless there is advanced panic buying)
• if profit margins get too high, this is usually quickly reversed by warnings from the consumer watchdog, intense media scrutiny and consumers checking prices at multiple stations, often using apps like Petrol Spy

• consider electric options if not doing remote driving or 4WD offroad
  • see 12V batteries, EV cars and camping
• fuel efficiency (L/100km travelled) vary enormously depending upon:
  • vehicle speed
    • peak is usually around 80kph then falls by about 10% for every 10kph increase
    • kinetic energy of a vehicle is proportional to the square of the velocity
  • idle time
    • city traffic results in much lower efficiency than highway
    • many newer cars automatically shut off the engine when stopped
  • driving habits
    • frequent or rapid accelerations substantially use more fuel than steady slow accelerations
  • hill climbing
    • substantially reduces efficiency on ascent but markedly reduces it again upon descent, but overall reduces efficiency
    • fuel and engine power required to create the potential energy of climbing a hill is proportional to mass x elevation gain
  • vehicle (and tow) weight
    • rolling resistance of a vehicle to maintain speed is proportional to total mass
    • fuel and engine power to get up to speed is also proportional to total mass
  • motor design
    • 4 cylinder engines are generally more fuel efficient than 6 cylinder or 8 cylinder engines
      • however, they may require turbo charging to generate sufficient power for a load or safe highway overtaking
    • hybrid electric vehicles are more fuel efficient again as they utilise braking to create electrical energy which can then be used to help power the vehicle
  • vehicle design
    • aerodynamics
      • in general, anything placed on the roof such as a rooftop tent, roof pods, lights, etc will significantly increase drag and reduce fuel efficiency
      • having car windows open will increase drag
      • lifting a 4WD 2“ will typically result in worsening of highway fuel economy by 0.2-0.4 L/100km or 3-6% due to increased frontal area - diesel 4WDs may fare better than petrol due to torque efficiency
    • tyres
      • under-inflated tyres reduce fuel efficiency
      • some tyres will be more fuel efficient than others
      • increasing tyre size as with doing a lift on 4WDs increases rolling resistance and rotational mass potentially dropping fuel efficiency by a further 0.2-0.4 L/100km
  • vehicle alternator demands
    • running the air conditioner in particular will increase demands on the alternator substantially which in turn increases demands on the engine resulting in fuel efficiency drop
  • wind speed and direction
    • a strong head wind or side wind will reduce fuel efficiency
  • road surface
  • fuel type
    • the octane rating is based on how quickly a fuel ignites in a standard combustion engine, not how much energy it has or fuel efficiency
      • the higher the octane rating, the more stable the fuel and the less likely it is to damage engine cylinders and rods
      • cars designed for premium petrol
        • some petrol cars are meant to use high octane petrol such as 95 or 98 instead of the usual 91 octane unleaded (eg high-compression or turbocharged models) and using 91 instead may reduce efficiency in these cars and potentially could reduce longevity of the engine
        • consider using E10 in non-turbo cars as it has higher octane at 94 RON than 91 RON and is cheaper than 95 RON - often 10% cheaper
      • cars designed for 91 RON petrol
        • using higher octane petrol like 95 or 98 RON instead of 91 RON typically provides no meaningful fuel efficiency gains in vehicles designed for 91 RON, as modern engines adjust timing automatically without benefiting from the extra knock resistance, indeed using premium fuels in these can actually DECREASE fuel efficiency by up to 11%, although some studies suggest a 2-3% gain may be possible when driving with heavy loads
        • no clear advantage to using E10 unless price is a lot cheaper
    • E10 is 3% less energy compared to 91 RON but can only be used in vehicles made after 2000 which are not turbo charged and do not have petrol carburettors
• fuel prices
  • these can vary substantially across the country, and tend to be especially high in remote areas and during fuel crises
  • avoid 98 RON Premium fuel
    • this will not provide more fuel efficiency over 95 RON for cars needing premium and neither 98 or 95 RON will give fuel cost savings for cars designed for 91 RON
  • using cheaper 94 RON E10 fuel probably is not useful for 91 RON cars but may be an affordable option for 95 RON cars
    • some cars built after 2000 which don't have turbo engines could use cheaper and possibly more environmentally friendly E10 fuel (could reduce greenhouse gas emissions by up to 5% if the ethanol is made from sugarcane and not corn or wheat) as they generally do not have petrol carburettors which are incompatible with E10 but as this contains 10% ethanol it produces 3% less energy per litre, so you will need 3% more fuel for same distance which may nullify any affordability gains
    • Australia produces nearly all of the ethanol we consume domestically, in any given year. This includes ethanol used in E10 fuel but this can only be made at the Australian refineries.

fuel efficiency in L/100km = power needed to maintain speed x 100 x 3.6/ (engine efficiency x speed x specific energy content of fuel)

where:

• 100 = 100 km
• 3.6 = conversion of kWh to MJ
• specific energy content of fuel in MJ/L - usually 32MJ/L for petrol
• speed in m/s (NB. 100kph = 27.8m/sec)
• energy and drivetrain efficiency - for internal combustion engines is usually 0.2-0.3

power needed to maintain speed on flat ground = rolling resistance + aerodynamic drag resistance

• rolling resistance = rolling‑resistance coefficient (0.01–0.015 for cars) x mass in kg x 9.8 m/s² (gravity) x speed in m/sec

• aerodynamic drag resistance = 0.5 x air density (~1.2 kg/m³ at sea level) x drag coefficient for vehicle x frontal area (m²) x (speed in m/sec)³

• Australia's fuel needs
  • in 2025, Australia imported 850,000 barrels per day of refined products (most of which is refined from Middle East oil) against total demand of about 1.1 mil barrels per day
  • Australia only has proven commercial reserves are around 229 million barrels of oil - not even enough for 7 months demand
  • 83% of Australian maritime imports move through the narrow maritime channels of Stheast Asia — Malacca, Lombok and Sunda strait
  • Australia is the world's largest importer of diesel - Australia's mining sector consumes approx 40% of the nation's diesel supply while farmers and truck transport utilise much of the remainder
  • Australia also imports most of its fertiliser and plastics which rely upon crude oil to manufacture
• Australian oil refineries
  • Australia now only has two oil refineries as a result of closures due to the companies saying the refineries were no longer economically viable because of competition from large, modern refineries in Asia and the Middle East (although Liberal governments were in power when these refineries closed, and their fuel-security policy was arguably inadequate):
    • together these normally can produce ~100,000 barrels of petrol a day - a third of Australia's needs
    • Brisbane
    • Viva Energy refinery at Geelong
      • supplies around 10% of Australia's petrol — and more than 50% of petrol in Victoria - via its national network of 1,500 Shell, Liberty and OTR services stations
      • can process up to 120,000 barrels of oil per day
      • a fire on 15th April 2026 took 13hrs to control
    • Kwinana and Altona closed in 2021
    • Kurnell and Bulwer Island closed in 2014 and 2015
• Australia has about 4 weeks of emergency reserves of fuel - although it should have 90 days worth
  • Australia has reserves of 1.6 billion litres of petrol, 2.7 billion litres of diesel and 800 million litres of jet fuel, this translates to 37 days worth of petrol, 30 days of diesel and 29 days of jet fuel - but most of this is kept in the US which may make demands upon it
    • in March 2020, Angus Taylor, Australia's Energy Minister under the Liberal-National Coalition government, decided to store part of Australia's emergency fuel supply (1-1.7 million barrels of Australian-owned oil) in Texas and Louisiana as there was insufficient domestic storage for Australia's International Energy Agency obligation for 90 days of reserves and after buying $94m worth of oil for initial US storage, in 2022, Taylor sold the oil amid the Ukraine crisis.
• imported oil to Australia
  • unfortunately, whilst Australia does export significant amounts of crude oil - mainly to southeast Asian countries, it now only has two oil refineries (Brisbane and Geelong), and thus relies heavily on regular fuel imports - mainly from South Korea, Singapore, Malaysia, India (and it gets 32% of its 2million barrels/month jet fuel from China)
    • the closure of six domestic oil refineries in the last 20 years, means Australia imports 90 per cent of its oil needs
    • South Korea sells Australia $12.75 billion of petrol (including diesel) but most of their oil comes from the Middle East.
    • another $8.5 billion came from Singapore (a third of this comes from Middle East)
      • Jurong Island in Singapore, a 32-square-kilometre patch of reclaimed land, is the centre of an Asian oil hub operated by ExxonMobil, Aster and Singapore Refining Company that supplies about 20% of Australia's refined oil and capable of processing 1.5 million barrels of crude a day and its Singapore's fuel price index is a significant determinant of Asia-Pacific refined fuel prices - it buys 2/3rds of its crude oil from Middle East and says its refineries have the flexibility to source crude from other regions in response to the oil crisis
      • but it seems Singapore does not supply us with diesel or jet fuel
    • Malaysia supplies 14 per cent of Australia's diesel, 10 per cent of its petrol and 11 per cent of its jet fuel, in return, Australia provides almost all of Malaysia's liquefied natural gas imports and a significant amount of agricultural goods - nearly 60 per cent of Malaysia's wheat and 75 per cent of its lamb and beef come from Australia - so selling diesel and fertiliser to Australia helps support this
    • additional refined petroleum came from India, Taiwan, China, Brunei and Japan.
    • only a few hundred million dollars worth came directly from the United Arab Emirates (UAE), and even less from Oman.
• Australia is the world's 3rd largest exporter of liquefied natural gas which may allow leverage to prioritise Asian fuel to be sent to Australia
• https://www.abc.net.au/news/2026-04-11/australia-fuel-supply-strait-hormuz-crisis/106533982 - its not looking good for rest of 2026, especially diesel and jet fuel

• in general, a specific oil refinery is optimised for a specific type and source of oil as all oil sources have different characteristics of oils - it is not easy to replace one source with another
• oil is refined by fractionating into various products including diesel, jet fuel (kerosene) and petroleum (gasoline) and is a critical component of many other products such as plastics, cosmetics, industrial oils, etc.
• prior to the crisis, the US had become the world's top producer (albeit lower quality than Persian Gulf oil) and there was a global over supply of oil due to countries like China dramatically changing to electricity instead of fuel
• China and India acquire much of their oil from Russia
• 20% of global crude oil passes through the Strait of Hormuz - hence any threat to this is likely to raise crude oil prices quickly and significantly
• shared with Qatar (where it is known as the North Field), Iran's South Pars natural gas field holds an estimated 14 trillion cubic meters of gas, roughly 8% of the world’s total reserves and accounts for over 70% of Iran’s domestic gas consumption and nearly all of its gas exports - it powers Iran’s electricity grid, its industrial desalination plants, and its massive petrochemical sector, and even under heavy sanctions, South Pars has remained the primary source of hard currency for the Revolutionary Guard (IRGC). The field relies on a complex web of offshore platforms, undersea pipelines, and massive onshore processing facilities at Assaluyeh. A coordinated strike using B-52s or Tomahawk missiles could trigger catastrophic “wellhead fires” that could burn for years, as well as risks depressurizing the entire reservoir or causing environmental seepage into Qatari waters. Without South Pars gas, Iran’s power grid would collapse within 48 hours. This would lead to a total shutdown of hospitals, water treatment, and food distribution, likely triggering internal civil unrest on a scale the regime could not contain, while causing an immediate spike in global gas prices impacting European and Asian markets instantly.
• a sustained reduction in crude oil of 10% is likely to reduce global GDP by about 10% based upon historical events and this points to a global recession with reduced food and commodity supplies, reduced employment and increased famines

• petrol stations began to raise prices earlier than usual in response to increases in wholesale prices compounded by panic buying causing shortages
• indeed, in late Feb, instead of their usual cycle peak declining, their prices and profit margins increased on fears of the oil crisis risk, but by Mar 3 when wholesale prices actually started to go up, they continued to raise prices and the differential of pricings between the states (Brisbane > Melb > Sydney) had practically disappeared
• in Mar 2026, China stopped exporting its jet fuel - 32% of Australia's jet fuel comes from China
• embargoes on Russian oil partly lifted
• on 15th Mar 2026, the government released up to 20 per cent of the baseline minimum stockholding obligation for petrol and diesel, targeting areas experiencing local supply disruptions
• by mid-March, the rapid increase in wholesale prices and consumer / govt pressures reduced the profit margins to only 4-10c/L across the country even when some petrol stations were running out of fuel ¹⁾ as diesel hit over $3/L up from $1.75/L before the crisis
• by mid-Mar 2026, 40 energy assets damaged or destroyed in the Middle East plus partial closure of the Strait of Hormuz = reduction of 11 million barrels oil per day and reduction of 140 billion cubic metres of natural gas for global supplies - in 1973 and in 1979 oil crises, the reduction was only 5 million barrels per day, while after the Russian invasion of Ukraine, the gas markets, especially in Europe, lost 75 billion cubic metres
  • allegedly, Iran's attacks have so far damaged or destroyed 30 - 40% of the refining capacity in the Gulf.
• Houthis of Yemen and the Bab al-Mandeb Strait of the Red Sea
  • handles 12% of global trade
  • any “closure” by Houthis hits freight, oil, insurance, supply chains, container routes, fertiliser, and every economy downstream
  • Houthis entered the war end of Mar 2026
• in late March, there were a total of five shipments carrying almost 2 million barrels of fuel to Australia from the US including 1.3 million barrels of petrol and nearly 600,000 barrels of diesel, scheduled to arrive from mid-April through early May
• Aust Govt halves fuel excise for a period of 3 months from end of March 2026 and will underwrite the delivery of additional cargoes of fuel.
• various Australian states including Victoria introduce free public transport for month of April 2026
• JP Morgan suggests most fuel shipments to Australia will stop by 20th April 2026
• unlike China and Sth Korea which have reduced of halted fuel exports, Singapore sees itself as having a reputation as a reliable refiner and is trying to maintain exports especially with Australia as it receives NGas and oil from Australia
  • Singapore imported shipments of crude and condensate — liquid hydrocarbons typically occurring with natural gas — from Russia, Brazil, the US and Venezuela rose in the first half of March 2026
• cost of oil shipping transport has apparently risen from ~$20,000 per day to $300,000 per day and some routes have been increased by 30 days of more to avoid the Persian Gulf - those countries which can afford to pay top dollar will be the ones who get priority oil
• US President becomes frustrated and unhinged with his Easter “tweets” including threatening annihilation of the Iranian civilisation
  • “Tuesday will be Power Plant Day, and Bridge Day, all wrapped up in one, in Iran, There will be nothing like it!!! Open the [F***in'] Strait, you crazy bastards, or you'll be living in Hell – JUST WATCH! Praise be to Allah. President DONALD J. TRUMP.”
  • then “A whole civilisation will die tonight, never to be brought back again. I don't want that to happen, but it probably will.”
  • threatened to bomb Iran “back to the Stone Ages”
  • according to one journalist, “this is not the messaging of strategy or international law — it’s the renewed language of the Crusades, driven by ideological fervour and staged as a performance of power…. This reflects a dangerous fusion of militarism, religious fundamentalism, spectacle and authoritarian politics that is redefining how military power is justified, experienced and normalized. … Pete Hegeseth, Trump’s defense secretary, expresses this world view most chillingly. He has declared that the mission of the U.S. military is “to unleash death and destruction from the sky all day long,” and has called for “maximum lethality, not tepid legality” as its guiding principle.” ²⁾
• April US-Iran 2 week “ceasefire”
  • the Iranian regime is still there, along with its supposed 440kg of 60% enriched uranium stockpile hidden deep underground and ability to control the Strait of Hormuz and Iran now demanding a $2m fee for ships passing the Strait, while much of the Persian Gulf's oil facilities have been severely damaged which will probably reduce global oil supplies by around 11 million barrels a day and maintain high oil prices for the foreseeable future even if the ceasefire holds.
• some Italian airports are running short of jet fuel impacting flights
• US now closing Strait of Hormuz to all ships and in response, Iran is threatening to close the Red Sea with the aid of the Yemen Houthis - this would seriously impact Saudi Arabia's oil exports to Asia
• April 16th 2026, Australia secures 570,000 barrels or 100 million litres of additional diesel from Brunei and South Korea purchased by Viva Energy with Aust Govt underwriting the risks