The first answer was a bit tongue and cheek.
Possibly the equation more likely can’t be calculated as infinity can’t be defined and therefore has no answer. If infinity could be defined mathematically, then it wouldn’t be infinity as it would be possible to have infinity + 1.
On topic then.
I doubt that is reliable advice applicable to the average modern vehicle in as sold condition. E10 after all is 90% or higher regular unleaded.
E10 blended fuel contains the same formula package as similar grade regular fuel. One well known expert has this to say.
The Australian car industry has demonstrated its support for ethanol blended petrol, reassuring drivers that E10 fuels are safe for 10% ethanol blend compatible vehicles and will not affect warranties.
It may help all of us if you can share some empirical data to aid our future decision making.
You may also have a very special example.
Yes, we need an appropriate emoji perhaps?
More directly it is a difficult choice between concise mathematics and being informative? I think we are failing there?
I was interested to read the comments that it is OK to run your mower on E10. I have been told very clearly by several mower service companies never to put E10 in a two or 4 stroke mower. I have several rideons, a push mower and whipper sniper. It costs a fair bit more to use '95 but I have been told numerous times to do it.
It looks like it can vary depending on the manufacturer of the motor. It appears that Briggs and Stratton motors are engineered to take e10, but others not.
It is best to check with the manufacturer if one is considering using e10 in a power tool or in other motor application such as outboard motors, to ensure that the manufacturer indicates that e10 is comparable with the motor.
It could be that the manufacture of the motor has not indicated e10 compatability, and why your local mower shop has indicated not to use it.
The other consideration is e10 (ethanol component) absorbs water and if one doesn’t use their power tools regularly, there could be water accumulation in the fuel tank.
Except that dirigibles tried that. Hydrogen is not stable. Neither is oxygen, for that matter - both are extremely reactive which is great for producing power but not so great when you’re trying to control that power.
When it comes to producing power for humans, we ideally want a power source that is either ‘effectively’ infinite (like the sun, since we die when it dies) or one that is reproducible - like products powered by the sun such as plants.
We are currently type 0 on the I - IV Kardashev scale for civilisations’ energy consumption (which considers, after detection, how to measure the technological capacities of extra-terrestrial life). A type II kind of technology is shown in Star Wars: The Force Awakens with the planet-busting beam.
Yes it is, sometimes? It is simply a matter of scale and not standing too close. EG The Sun. Although ultimately it too will become unstable.
On the more mundane issue of powering 2 or 4 stroke yard equipment! As they are not quite ready for the transition to self contained nuclear power.
If the manufacturer says it can run on E10 then it is ok to do so. My Toro (Kohler Vee-twin) can and also the Honda FP and generator. In practice I never use E10 for any or the other petrol powered tools. There is no cost saving.
E10 looses volatiles rapidly over only a few weeks, which marginally decreases the fuel quality and ease of starting. Overtime there is a risk of water absorption in the ethanol portion of the E10 caused by condensation in part empty fuel tanks or storage containers. Not likely a risk if you maintain the fuel tanks at full at the end of a working day, and the turn over or use of fuel is high. A full tank weekly! It’s also important to keep all the equipment under cover, and not in the open to minimise condensation.
The same good practice is useful with regular unleaded, although leaving these small motors unused for more than a few weeks at a time, it is better to drain the fuel systems and follow the manufacturers storage procedure. There are fuel additives that act as stabilisers that may be useful in some circumstances, although I have not researched if there is any difference in outcomes with E10 fuel.
On a totally different path the range of powered yard equipment that is battery powered has continued to expand. Stihl is one supplier with a usable number of options including chainsaws etc. Perhaps a better option than petrol powered (E10 included) for home and light farm use. Our fencer and land contractors have made the change. The extra cost is offset in part by convenience and reduced maintenance needs.
The sun is an ongoing, absolutely enormous explosion - that’s not stable! (And yes, I am simplifying how the sun converts hydrogen to helium using nuclear fusion.) Hydrogen is a reactive non-metal - meaning unstable.
The sun looks very much the same today as it did yesterday.
In this one instance I am happy to remain fooled by innocence, rather than being blinded by science.
I’ll reserve science for less ‘critical’ events, just noting that the sun is zero carbon. I noted the reference to Kardashev responds to energy needs, without making any judgement on the environmental.
In summary some of the points so far suggest:
If anyone has a reference to any published scientific work on the Australian industry it may further our understanding of the local situation as to net benefit.
A detailed analysis of the Brazilian (sugar cane) and USA (corn syrup) production had this to say.
The use of ethanol as a substitute for gasoline proved to be
neither a sustainable nor an environmentally friendly option.
Considering ecological footprint values, both net energy
and CO2 offset considerations seemed relatively unimportant
compared to the ecological footprint. As revealed by the ecological footprint approach, the direct and indirect environmental impacts of growing, harvesting, and converting biomass to ethanol far exceed any value in developing this alternative energy resource on a large scale.
True there are many infinities. Doing arithmetic with any of them is perilous and only useful in pure mathematics, not being a very pure mathematician I should be quiet now.
“One pill makes you larger, and one pill makes you small
And the ones that mother gives you, don’t do anything at all”
No more white rabbit chasing, back to fuel.
Talking generally about fossil fuel-powered engines, you need to be careful because the manufacturer (branding) on the engine may be different from the manufacturer (branding) on the unit as a whole.
My choice is to avoid E10 on everything except cars. If the main reason for using E10 is the environmental benefit then the number of kilometres “equivalent” that I might do on, say, a push mower is tiny compared with the number of kilometres in a car - while the hassle and risk of getting good info about E10 compatibility for those additional engines is higher.
So if it is petrol powered then I will use Unleaded 91.
Although as a comparison with petrol, the situation is likely even worse with petrol. We import a lot of crude oil and as we phase out all domestic refining we will eventually import 100% of our refined product.
On top of that we aren’t even “compliant” with the required 90-day stockpile of the various products. So our energy security posture is weak. In the event of a hot war causing substantial supply disruption we would be stuffed, to put it politely. It is a fairly complacent position.
That basically applies to all fuels. The point of a fuel is that the fuel can be used to release stored energy and to do so at high power (energy released per unit time) and high energy density (energy stored per unit volume or mass of fuel).
An actual hydrogen powered car gets fairly ugly if it catches on fire but the same is true of your typical petrol vehicle.
It needs good engineering to extract the energy from the fuel as safely as possible, but it is never risk free.
That’s not directly comparable though because in those cases the hydrogen was used statically, and without consumption as such, as a lifting gas, rather than as a fuel - well, not intentionally as a fuel. 
Propulsion of the airship is provided by an engine that likely will not use hydrogen as a fuel.
However all of those incidents do indeed illustrate that hydrogen is highly explosive, and dangerous when things go wrong.
Mustang:
E10. Unlike other fuels it contains no lubricant additives and that’s not good news for things like injectors which are expensive items and need them. A reliable source has also told me that for the same reason it’s not great for fuel pumps.
I doubt that is reliable advice applicable to the average modern vehicle in as sold condition. E10 after all is 90% or higher regular unleaded.
E10 blended fuel contains the same formula package as similar grade regular fuel. One well known expert has this to say.
Shell Unleaded is specially designed to give you extra kilometres by helping combat efficiency losses caused by deposits in your engine
The Australian car industry has demonstrated its support for ethanol blended petrol, reassuring drivers that E10 fuels are safe for 10% ethanol blend compatible vehicles and will not affect warranties.
Regarding reliable sources, Shell sells E10 so there’s a conflict of interest. Try taking them on and proving it was E10 that caused your car to fail outside warranty . See below for a link to another well know expert, albeit this time one that doesn’t sell the product. My source has seen the effects of it across a large sample size for many years and has nothing to gain from its sale.
Mustang:
I use 98 whenever I can get it. Yes it’s dear but the increased response and improved economy (by about 10% in my experience
phb:
It may help all of us if you can share some empirical data to aid our future decision making.
You may also have a very special example.
Mustang:
No, nothing special here at all. Empirical evidence? Tracking fuel economy under similar conditions for several weeks using both E10 and 98 is as good as it gets. It was enough of a difference to make 98 a no brainer. As for performance increases, again nothing tested under lab conditions unfortunately but the lab of my pants seat has been a good indicator for many years of driving and riding high performance factory vehicles; if the difference is positive and noticeable, then it’s all I need. Of course if you can feel it then there’s likely to be a significant difference, as opposed to differences to small to feel that can only be measured with instruments.
A random Google search found what another expert had to say, albeit one that doesn’t sell E10, and I believe there are further articles on the Royal Chemical Society website:
Ethanol, which is produced from corn, is commonly-used as an additive in engine fuel as a way to reduce harmful emissions and scale back U.S. reliance on foreign oil. But since ethanol is an oxygenated fuel, its use results in a lower energy output, as well as increased damage to engines via corrosion.
It turns out my car manufacturer DOES recommend Premium 98. The link suggested above gave the impression that only turbo charged vehicles would benefit from using it.
I have two modern European cars with relatively small, turbo charged engines which the handbooks state should use a minimum of 95 octane petrol. As 94 octane E10 is much cheaper than 95 ULP I have run both cars mainly on E10 with no noticeable difference in performance and certainly no audible pinging. I keep a record of all fuel purchases and use spreadsheets that calculate trip and overall average fuel consumption but any difference between the two fuels is too small to register.
One of the cars has done over 70,000kms and has performed faultlessly, the other is near new and also runs as it should.
all assuming that your manufacturer has documented that it is acceptable to use E10 at all in those cars.
We informally monitor our fuel consumption (L/100km) but there is such variability due to e.g. highway cycle v. city cycle and e.g. got caught in 10 km traffic jam due to accident on highway, or whatever, that any difference between fuels is too difficult to isolate. That is, for our situation, the only way we could detect any difference between E10 and unleaded would be to drive the same journeys every tank and avoid any significant traffic jams i.e. not.going.to.happen.
Yes, and a check for compatibility can be undertaken using the second link at the top of the thread in the popular links section. It is titled ‘Compatibility Check | e10 nsw.gov.au’.
This comparability checker uses information sourced from the vehicle manufacturers.
If there is no information from the manufacturer about the vehicle’s compatibility with ethanol blends, then the vehicle will not be listed on the comparability database. In such cases, seek information directly from the vehicle manufacturer in relation to the comparability of using e10 in the vehicle.
If a vehicle is listed as being compatible, the use of e10 in the vehicle will not void warranties as it is specifically recommended for use by the manufacturer/nominated as being compatible by the manufacturer.
