The widespread adoption of E10 petrol is now complete, with almost every forecourt across the UK dispensing it from the green pump. It was in September 2021 that the government announced the enhanced ethanol-mix fuel would become the new standard grade of unleaded petrol across Great Britain, citing its lower CO2 emissions compared with the previous E5 blend. Northern Ireland followed suit in November 2022.
Many may not have noticed the changeover to E10 fuel, but question marks remain over its adoption – from whether your car is able to run on it, to whether it reduces fuel economy, if it’s okay to mix it with E5 petrol, and much more besides.
We explain everything you need to know about E10 fuel in this comprehensive guide.
What is E10?
In order to make conventional fuels less environmentally harmful, it was decided to blend in some renewable content such as biodiesel and ethanol. This is nothing new: it has been going on with petrol and diesel in the UK since the early 2010s.
Ethanol is an alcohol fuel that’s produced from a range of plants, including sugar cane and grains. The upside is that, unlike regular unleaded petrol, growing the crops that make ethanol actually absorbs CO2, partially offsetting greenhouse gas emissions.
Before the introduction of E10, the standard unleaded petrol was called E5 and made up of 95% regular unleaded petrol and 5% renewable ethanol – hence the name.
Diesel remains as B7, made up of 7% biodiesel.
Blending renewable fuels in this way has reputedly contributed to a CO2 emissions reduction equal to taking more than a million cars off the road.
E10 was introduced to further reduce the emissions produced by petrol vehicles by doubling the amount of ethanol used to 10%.
The UK government estimated that its widespread adoption could reduce CO2 output by 2%. That might not seem like a huge amount, but as Britain moves towards a net-zero-carbon future, every little helps.
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I did my first long run to Wales earlier this week since E10 was introduced and I will admit the fuel consumption has increased, averaging about 46 mpg compared to around 48 mpg I got a couple of years ago when I did the same run. Honestly can't say that I noticed any difference in performance either. Maybe some engine work better with E10 than others.
BTW my car is a 2006 Vectra with the 1.8L VVT engine.
The car should be OK with E10, but our boat outboards, lawnmower, strimmer etc probably not.
We already had trouble with using E5 petrol in a Mercury two stroke outboard some years back.
The fuel line to the plastic tank had a plastic vapour lining which was disolved by the ethanol in the petrol. This plastic lining was to stop petrol vapour escaping into the environment, and was apparently to comply with legislation in the USA.
This resulted in the engine running on fuel heavily contaminated with plastic, until it cut out due to a blockage, it also contaminated the petrol in the fuel tank turning it yellow, so it had to be dumped.
Ethanol also absorbs water vapour which can result in a layer of ethanol disolved in water at the bottom of the tank with the petrol sitting on top. I've also read it doesn't keep well.
I have an issue where I have had to replace the O2 sensors post andd pre cat, as this is what the diagnostic tool advised. My thinking is around the fuel air mixture monitoring by the ecu is now sending errors and illuminating the engine management light.
So if it burns at a different rate does the ecu neeed to be remapped to take this into consideration.
My vehicle is 65 plate Ford EcoSport.