Ethanol and emission reductions/biodiesel and emission reductions

In Australia in 2014, our gasoline demand equaled 18,000,000,000 litres of fuel. According to the Australia’s National Greenhouse Accounts (NGA) 2.33kg of CO2 is emitted for every litre combusted in an engine.  So in terms of Australia’s 2014 consumption of petrol, we emitted 41,306,76,000kgs or 41.3 million tonnes of CO2.

The use of ethanol blended fuels is another vital tool in our fight against climate change and global warming. Ethanol blended fuels can significantly reduce our greenhouse gas emissions over their entire lifecycle, from production through to use in the vehicle.

The NGA also states that one litre of ethanol reduces net emissions of CO2 by over 99%, so one litre of ethanol will save approximately 2.3kg of CO2.

The US EPA estimates that on a Life Cycle Analysis basis, one litre of cellulosic ethanol reduces net emissions of CO2 by over 90.9%, so one litre of ethanol will save 2.11kg of CO2.  So by replacing Australia’s total annual consumption of gasoline with E10 (Ethanol 10% Blend), we would reduce our CO2 emissions to 4 million tonnes.

At the moment ethanol is generally blended with ordinary petrol up to 10% by volume (E10).  However there have been strong moves by many car manufacturers globally to move to E85 compatible – 85% ethanol. If all cars were E85 compatible, we have the potential to save about 35 million tonnes of CO2 each year.

Ethanol not only reduces carbon dioxide emission, but it also reduces many other harmful carcinogenic and particulate emissions from petrol engine emissions.  A recent study (Costagliola, 2012) showed whilst there was an increase in acetaldehyde, there was a reduction in benzene and 1,3 butadiene emissions (known carcinogens) and reductions in PAH (Polycyclic Aromatic Hydrocarbons) by 30-70%

Ultrafine particulate matter is becoming of increasing significance with the World Health Organisation declaring particulate exhaust from diesel as carcinogenic.  As a result, all particulate emissions are being reassessed.  Ethanol in the same study was shown to produce significant reductions in ultrafine particulate emissions (Particulate Matter less than 1μm) of up to 90% being observed.

Ethanol therefore is not only a pathway to lower CO2 emissions but also cleaner air for us to breathe.