June 10, 2010

Horse 1093 - E10 Is A Waste Of Time... or...

... Why I No Longer Drive To Work

As at July 1st, normal undiluted 91 Octane petrol will cease to be sold in Australia. Instead, we'll no be forced to buy this E10 rubbish.
Rubbish? Isn't E10 supposedly better? More environmentally friendly? Isn't it supposed to make my car fart flowers?

WARNING: SCIENCE AHEAD

E10 is a blended petrol made from two broad components.
1. Octane - C8H18, and octane like components.
2. Ethyl-alcohol (or Ethanol) - C2O6H.

Unlike the Octane Rating* which is a measure of burn rates, there actually is a chemical difference between C8H18 (octane) and C2O6H (ethyl-alcohol or ethanol). In general pure ethanol contains 34% less energy than pure octane (which isn't sold at the pump anyway).

Therefore an E10 fuel is going to provide 96.6% of the energy of an E0 (0% ethanol fuel) and only going to give you 96.6% of the mileage at best. At the current discount rate of 4c a litre (or even 3c at crappy stations) E10 petrol is only going to work out cheaper in the long run if the petrol is less than 103.51c/L (as that's the breakeven point). At any price more than that, you'll be doing your dosh because by saving 4c/L you'll be undoing it by only having 96.6% of the energy available on tap.

What's even better about this is that my calculations match up in the real world:
http://www.smh.com.au/news/motoring/news/false-economy/2008/12/12/1228585078909.html
A fuel derived from plants might appear to be a cheap and green alternative but exclusive Drive research proves this is not the case. A fuel-efficiency showdown between the three most-popular types of petrol on the market concludes the ethanol blend will cost you more in the long run and may not even help the environment.

City driving exposed E10's efficiency shortcomings more than highway cruising. Around town, using E10 was almost as expensive as using premium unleaded, despite the huge gap in pump prices.

In the 700 kilometres of city driving, our E10 Camry used almost 10 litres more fuel than our premium-fuel car.
The comparative fuel bills for the three cars were: E10, $105; premium, $105.91 (15c/L more expensive); and regular unleaded, $100.33.
Had we used thirstier six-cylinder cars or less-efficient used cars, the equation would probably have strengthened further in favour of unleaded and premium fuel.


In general ethanol petrol isn't cheaper in the long run. I'm not even a scientist and I could work that out.
There was even another factor in my calculations. The new MyZone2 ticket costs $48, or what would work out to be $5.33 cheaper than the new calculated fuel bill to get to work in my Ka.

In short, E10 is a waste of time and ironically was the thing which put me back on public transport.

*For futher reading on Octane Rating:
http://rollo75.blogspot.com/2007/12/horse-837-high-octane-fuel-do-you.html

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