E10 fuel soon to replace E5 at UK filling stations

Is your car one of the 5% of petrol-powered cars incompatible with E10 fuel and how will this affect your car?

When I fueled my 3 year old Vauxhall Corsa at the forecourt of a well-known supermarket filling station this morning, I couldn’t fail but notice the brightly coloured warning notices dotted at every entrance. As of 1 September 2021, the standard unleaded petrol at the pumps will change from E5 to E10.

My partner, who pulled up on his motorbike shortly afterwards, had the same visual moment of realisation. What was the consequence for our respective vehicles and what would be the cost?

If you are on that same fact-finding mission now, we're here to help.

What is E10 fuel?

The standard unleaded petrol we are used to consists of 5% ethanol, hence the name E5.

As you can probably guess: this proportion of ethanol will increase to 10% in E10 petrol.

Ethanol is crucial to the composition of petrol as far as the environment is concerned. This is because it is a type of alcohol manufactured entirely from plants and is therefore classed as renewable energy. It’s introduction, then, is designed to reduce the carbon footprint of our cars.

By reducing the fossil fuels required to power the UK’s cars, E10 fuel will reduce CO2 based vehicle emissions. HM Government claims to “the equivalent of taking 350,000 cars off the road”.

Once complete, the UK will be in line with the many other nations worldwide already adopting E10 as the standard petrol for their cars. This includes Belgium, France, Germany, Slovakia, Estonia, and many more.

E10 petrol is already the fuel of choice for all new car emissions and performance testing and has been since 2016.

Can my car use E10 fuel?

The potential downside to the imminent arrival of E10 fuel is that it isn’t compatible with all vehicles.

While 95% of the UK’s current cohort of petrol drivers will make the change without a hitch, there’s 5% that will have to take notice.

All new cars manufactured since 2011 are compatible with the new E10 fuel. This, HM Government states, means that the arrival of E10 should not impact most of the UK’s 33 million drivers. That’s great news for me and my partner, and if you are looking for a new car lease deal.

However, owners of older, classic or cherished vehicles and some mopeds (50cc and under particularly) are not so lucky.

To check whether your vehicle is compatible with E10 fuel, use this handy vehicle checker. But note they won't accept liability if the information proves incorrect. So it's worth checking the manual of cars that are ten years or older, just in case.

The same applies for petrol powered tools or machinery including boats, lawn mowers or chainsaws. In these cases, we are being advised to check user manuals or contact the manufacturer for confirmation.

Diesel fueled cars will be completely unaffected.

What if my vehicle isn’t compatible with E10 fuel?

If you are one of the 5% whose vehicle can’t make the seamless evolution to E10 petrol, you will have to start using a super grade or premium unleaded option instead.

Most of us should be used to seeing this sit alongside standard E5 on fuel forecourts. Premium unleaded will remain compatible with older cars as it contains the same 5% proportion of ethanol. However, the higher rating of octane comes with the expectation of better driving performance in high performance cars, and therefore comes at a higher cost.

All petrol cars are manufactured to work with super grade petrol as well as E5, so if you are currently a premium user there is no obligation to stop.

Once you’ve established whether E10 or premium E5 are right for your car, we are assured that our fuel pumps will be clearly labelled to reflect the change. Nevertheless, it will be worth a second look instead of instinctively going for the same pump and nozzle you’ve used a hundred times before.

The pros and cons of premium unleaded

High performance cars are most likely to reap the benefits of using premium or super grade petrol. In these cases, drivers may notice improved throttle response, power, and overall efficiency.

Smaller, less exciting cars like my Corsa are unlikely to feel the same results.

However, an inflated MPG is possible no matter what you drive. Some premium petrol is known to reduce friction and help clean the engine, in turn allowing your car to run more efficiently.

We’ve mentioned cost, and it could be significant depending on your mileage. Based on the RAC's fuel watch calculator, at time of publishing on 29th July, standard unleaded is 134.32ppl while super unleaded is 144.41ppl. That’s a difference of 10.09ppl and amounts to over £4 extra at each of my 40L fuel refills. 

E10 fuel availability

While E10 petrol will become the standard supplied across our country’s forecourts, it is important to note that more rural or small petrol providers may not be able to offer both E10 and high-octane petrol grades.

What will happen if you use E10 fuel wrongly?

The increase in ethanol contents in E10 petrol means it isn’t compatible in all vehicles that E5 is. It is suggested that the occasional misuse would be harmless. Your vehicle will still run and there would be no need to empty the tank like a miss-fuel with diesel.

However, prolonged use of E10 in a vehicle or mechanism not suited to it could lead to costly and dangerous repairs. Most commonly, blocked fuel filters, damaged fuel pumps, fuel hoses degradation and corroded carburettor.

The mixing of E5, premium or super grade unleaded and E10 is also fine. So there’s no need to fret at your first top up after the change takes place.

The pros and cons of E10 fuel

Although E10 fuel is expected to be the cheaper option between E10 and E5 premium unleaded, it may not be as clear cut as it seems.

A reduction of 0.2ppl was predicted within the Department of Transport’s impact assessment.

However, the change could increase overall running costs for drivers like me as HM Government suggests a reduction of around 1% in fuel economy for users of E10 fuel.

With cost per litre down but more fuel required for the same miles, the playing field seems less disastrous for those with older cars.

Notably, HM government is keen to point out that “Using E10 fuel will not affect whether you are able to drive in, or have to pay to enter, a clean air zone (CAZ), low emission zone (LEZ) or ultra-low emission zone (ULEZ)."

This exemption is determined by the vehicle’s Euro emissions standard, not by the fuel used. And, as mentioned earlier, emissions standards have been set using E10 petrol for some time already.

How green is E10 fuel?

The true environmental savings of E10 have been widely debated.

The benefits of increased use of ethanol within E10 fuel are clear and uncontested:

• Lowering CO2 emissions
• Reduced use of fossil fuels
• Non-toxic and renewable
• Easy to source and produce
• Valuable by-products that can support other industries and reduce importation

Others claim the ethanol in E10 fuel is carbon neutral: the CO2 the plants absorb during growth offsets that produced when it is burnt.

However, more fuel (both the good 10% and the bad 90%) will be required to travel the same miles. If the 1% decline in efficiency holds true, the environmental impacts will be tangible. However, if efficiency declines prove greater, it remains to be seen whether this will increase the volumes of the bad 90% in use in the UK overall.

Should I use E10 fuel?

If your car is compatible with E10 fuel, it will become the most easily sourced and cost-effective option for you.

Simon Williams, RAC fuel spokesman, helpfully concludes: “The switch to E10 petrol is clearly good news for the environment and will not affect the vast majority of the UK’s 33m car drivers although some may see the number of miles they get from a tank go down as research suggests E10 is potentially slightly less efficient.

“It’s estimated that around 700,000 cars registered prior to 2002 shouldn’t use E10 as seals, plastics and metals may be damaged by its corrosive properties if used exclusively over longer periods.

"It’s vital that anyone with an older vehicle gets the message about the switch otherwise they could end up with a big repair bill.

"There’s also a danger that E5 premium grade petrol may be harder to find in some more rural locations.”

The arrival of E10 doesn't come without its pot holes. But for those not yet ready to take the leap into a fully electric lease car, it provides another small way for us to do our bit to reduce the CO2 emissions caused on our roads. 

Petrol price changes are nothing new. Find out more about why petrol prices have risen to a record high in 2021.