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A couple of weeks ago I decided to set myself a challenge: to do something personal about climate change each month. My challenge for September was to find out which was the least damaging petrol for the environment. Spending time in the bush at Tapitallee is a wonderful antidote to the pressures of city living, but driving down here is an environmental burden.

It turned out there was no simple answer to my question. And the answers I found were dispiriting – more evidence of woeful environmental leadership in Australia. The articles on the subject were unanimous – ‘compared with most of the rest of the world, our fuel is filthy’[1]  and ‘… this country still uses much dirtier fuel than most of the rest of the world. Indeed, Australia is ranked 70th in terms of fuel quality because of the relatively high percentage of sulphur permitted.’[2]  and ‘Australia’s 91-octane standard fuel is allowed to have sulphur levels as high as 150 parts per million. The world standard in markets such as China, Europe, India and Japan is 10 ppm.’[3]

The levels of sulphur in our petrol are a problem because our petrol is ‘pumping significantly more sulphur dioxide – a common cause of breathing problems and generator of acid rain – into the atmosphere than other OECD members, creating excessive engine wear for consumers and even costing us more at the pump, because the dirty fuel doesn’t burn as efficiently as if it had less sulphur.’[4] Moreover, because our petrol has these high levels of sulphur, ‘the latest-technology, low-emission engines cannot be supported in the domestic market. “If you go to a higher quality fuel, the vast majority of vehicles on our roads automatically (become) more fuel efficient,” said Mr Weber [chief executive of the Federal Chamber of Automotive Industries (FCAI)]. “There would be an improvement in the fuel economy of vehicles across the fleet of 17 million vehicles in Australia, not just the new ones”.’[5] The FCAI has said that ‘improving Australia’s fuel quality would offer a “3% to 5%” improvement on CO2 performance “overnight”.’[6]

We have four types of petrol available: 91RON, 95RON, 98RON and E10. (RON means Research Octane Number – ‘Octane is the measure of a fuel’s ability to resist the phenomenon known as ‘knocking’ … [which] is the uncontrolled combustion of fuel that can destroy engine internals.’[7]) 91RON petrol has a 150 ppm sulphur content, while 95RON and 98RON have a 50 ppm sulphur content. So even our best petrol has five times more sulphur than the world standard.

E10 is not the obvious choice either. ‘E10 is a blend of regular unleaded (RON 91) petrol and between 9% and 10% ethanol. Blending the ethanol at this ratio increases the RON to 94.’[8] So E10 has 90% of the sulphur of 91RON petrol (so, 135 ppm). The manufacture of the ethanol is probably less environmentally detrimental than the production of petrol, and ethanol ‘is a clean burning fuel that produces less greenhouse gases than unleaded petrol’[9]. However, ‘the sustainability certification of Australian produced ethanol is not transparent. We know from studies conducted by organisations including the European Commission that when coal is used to produce ethanol, it can result in “little or no greenhouse gas emissions saving for ethanol compared to gasoline” on a well-to-wheel basis. This is a significant consideration for Australia, given our current reliance on fossil fuels.’[10] Also, ‘E10 has around 3% less energy than the equivalent amount of RON 91 petrol. On average, this can translate to an increase in fuel consumption of around 3%, which has about the same effect on fuel consumption as driving on tyres with inadequate air pressure.’[11]

So what, I hear you clamour, is our government doing about this? High levels of sulphur polluting our air and choking our people; dirty fuel leaving us unable to use the latest technology of low-emissions vehicles; unclear certification on ethanol – surely they’re keen to listen to the Federal Chamber of Automotive Industries and improve our CO2 performance ‘overnight’?

Well, in December 2016 the Department of the Environment and Energy released a discussion paper called ‘Better fuel for cleaner air’ which set out the problem succinctly:

  • Motor vehicle emissions can be split into two categories: noxious emissions which affect human health and the environment and contribute to respiratory illness, cardiovascular diseases and cancer, and greenhouse gas emissions which contribute to climate change.
  • Petrol fuelled light vehicle emissions are one of the major causes of air pollution in urban Australia. Our expanding vehicle feet, increasing urbanisation and aging population mean that further action is needed to improve air quality and reduce the health impacts of air pollution.
  • Improving fuel quality can help reduce the level of noxious emissions, which improves air quality and health outcomes.
  • Some advanced vehicle technologies (including advanced emissions control systems and certain fuel efficient engine technologies) require higher quality fuel to work effectively. The quality of fuel influences which engine and emission control technologies can be supplied to the Australian market.

It also states that ‘Catalytic converters in vehicles are designed to filter emissions and reduce noxious substances emitted from vehicles. Sulfur clogs the catalytic converters making them less effective.’ It then outlines five alternative approaches, ranging from ‘no change’ through to the staged introduction of world standards from 2020. Sadly, the decision that was reached was closer to the ‘no change’ than introducing the world standards[12]. The sulphur in petrol will be reduced to 10 ppm – from July 1 2027. The aromatic content in petrol will be reduced from 42 per cent to 35 per cent, effective 1 January 2022, to be reviewed and reduced by 2027. [‘Aromatic content’ refers to chemicals like benzene, toluene and xylene used to increase the petrol’s octane rating since lead was banned. The effect of these chemicals is being increasingly questioned. ‘The chemicals get released into the air as nano-sized particles – ultrafine particulate matter, or UFPs – that can be absorbed through the lungs or skin. Studies in peer-reviewed journals like the Journal of Environmental Science and HealthEnvironmental Health Perspectives and Particle and Environmental Toxicology, have linked these particles from aromatics to diseases ranging from ADHD to asthma.’[13]]

So where does that leave us? I’m thinking that E10 is only 10% ethanol, has 135 ppm sulphur, is less efficient, and even the production of the ethanol is not necessarily clean. So for now I’m opting for the petrols with less sulfur (RON95 and RON98). But I’m also looking into carbon offsets, and electric cars. My October challenge.






[1] https://www.whichcar.com.au/features/australias-petrol-is-one-of-the-dirtiest-in-the-world

[2] https://www.afr.com/opinion/cleaner-petrol-a-bigger-help-than-electric-cars-20180124-h0nnfg

[3] https://www.canberratimes.com.au/story/6079636/our-poor-quality-petrol-slows-the-drive-to-improved-emissions/

[4] https://www.whichcar.com.au/features/australias-petrol-is-one-of-the-dirtiest-in-the-world

[5] https://www.caradvice.com.au/714921/why-australia-needs-better-quality-fuel/

[6] https://www.theguardian.com/australia-news/2019/sep/02/eu-to-push-australia-to-clean-up-petrol-standards-as-part-of-free-trade-deal

[7] https://www.mynrma.com.au/membership/my-nrma-app/fuel-resources/can-premium-fuels-clean-your-engine

[8] https://www.e10fuelforthought.nsw.gov.au/facts

[9] https://www.racq.com.au/cars-and-driving/cars/owning-and-maintaining-a-car/facts-about-fuels/ethanol

[10] https://www.abc.net.au/news/2018-07-04/e10-cheapest-petrol-fuel-emissions-biofuels-ethanol-australia/9922938

[11] https://www.e10fuelforthought.nsw.gov.au/facts

[12] https://www.environment.gov.au/protection/fuel-quality/standards

[13] https://morningconsult.com/2015/04/22/growing-chorus-of-complaints-on-chemicals-in-gasoline/