What is E10 fuel and how will it affect you?

It’s estimated that the greener fuel could reduce CO2 emissions by 750,000 tonnes per year, the equivalent of taking up to 350,000 cars off the road.

Current petrol grades in the UK contain up to 5% bioethanol, known as E5. The proposed E10 fuel increases the share of the renewable energy produced using crops, to 10%.

Estimates fail to mention, however, that there could be as many as 600,000 vehicles on our roads that aren’t compatible with the fuel.

Here is a look at the pros and cons of using this new fuel as a genuine answer to increasing emission issues.

E10 is a biofuel made up of 90% regular unleaded and 10% ethanol – hence the E10 name.

Standard unleaded fuel contains up to 5% ethanol and can be used in any petrol-engined car without problems or the need for modification.

With E10, things aren’t quite so simple, which is why its roll-out in the UK compared to other European countries has been delayed.

Ethanol is an alcohol-based fuel produced from the fermentation of a range of plants, including sugarcane and grains, along with their by-products.

Unlike regular unleaded petrol, ethanol fuel is said to be partially atmospherically carbon-neutral. This is because as the plants that will become biofuel grow, they reportedly absorb more carbon dioxide than what will be released into the air during fuel production and combustion¹.

This partially offsets the greenhouse gas emissions produced by its production and use, but by just how much is still an active topic of debate.

In short, no. As many as 600,000 vehicles on our roads in 2020 aren't compatible with E10 - you can see if your car is compatible with the new fuel by visiting the official E10 online checker.

Drivers are advised to contact car manufacturers with any questions surrounding their specific vehicle. For example, Vauxhall says “E10 fuel can be used in all petrol-engine Vauxhall vehicles except models with the 2.2-litre direct-injection petrol engine (code Z22YH) used in Vectra, Signum and Zafira.”

As a rule, drivers of cars registered prior to 2002 are advised not to use E10 in their vehicle, as problems have been reported. And as of 2011, all new cars sold in the UK must be E10 compatible.

The RAC understands that if you put E10 fuel in an incompatible car it will still run, but seals, plastics and metals may be damaged over longer periods as a result of bioethanol's corrosive properties. 

There have also been reports that E10 is a less stable fuel and that this can make it more difficult to start a vehicle that has not been driven for an extended period.

The consequence of putting E10 fuel in an incompatible vehicle depends on the vehicle/engine variant and how much fuel has been put in.

It may cause some pre-detonation (‘pinking’), and perhaps a little rough running and poor cold starting, but it shouldn't be a disaster for the driver.

Simply top up with the correct fuel suitable for the vehicle as soon as possible when around a third to half the tank is used.

Although RAC Breakdown Cover members have access to a discounted Fuel Drain Patrol service, a drain shouldn't be necessary unless in the highly unlikely event that the engine would not run at all.

This depends on who you speak to. Environmental groups will point to carbon-offsetting properties, while the government will be keen to introduce E10 as a step towards meeting its emissions targets.

But research carried out by What Car? revealed that E10 is potentially less efficient than the current E5 blend of fuel, with the problem exacerbated in smaller-engined cars.

If true, this would lead to drivers filling up more often, increasing the cost of their annual fuel bill.

The US Energy Information Administration (EIA) claims the energy content of ethanol is about 33% less than pure unleaded and that "the impact of fuel ethanol on vehicle fuel economy varies depending on the amount of denaturant that is added to the ethanol."²

The EIA states: “The energy content of denaturant is about equal to the energy content of pure gasoline (petrol). In general, vehicle fuel economy may decrease by about 3% when using E10".

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Reacting to proposals to introduce E10 petrol in the UK, RAC fuel spokesman Simon Williams said:

“Everybody agrees that steps must be taken to reduce emissions from road transport, however introducing E10 as the standard petrol will pose some challenges. 

"Firstly, as the RAC Foundation points out, there could be as many as 600,000 vehicles on our roads that aren’t compatible with the fuel.

"Many of these are likely to be owned by those from lower income backgrounds and while it is welcome that E5 petrol is not being phased out altogether, owners of these vehicles will face higher fuel costs – and will also have to hunt out those forecourts that still sell E5.

"Some retailers will also not have the capacity to be able to provide both E5 and E10 fuels on forecourts, so the impact is likely to be most keenly felt by those with incompatible vehicles in rural areas.

"It is also vital that owners of affected vehicles are aware of the changes. We’d like to see the DVLA writing to these owners to inform them that E5 will no longer be the standard premium grade, and to let them know their options.

"This, alongside a trusted online resource where drivers can quickly identify if their vehicles are E10 compatible or not, will go a long way to avoiding any expensive problems from filling up wrongly with the new blend.

"For the overwhelming majority of drivers with compatible vehicles, the introduction of E10 petrol will make little difference other than a possible slight reduction in fuel economy."

Drivers of older, incompatible cars may have to shell out for more expensive fuel, since forecourts will likely only offer E5 as a premium option.

It’s estimated that the greener fuel could reduce CO2 emissions by 750,000 tonnes per year, the equivalent of taking up to 350,000 cars off the road in the UK.

Transport Secretary Grant Shapps said: “The next 15 years will be absolutely crucial for slashing emissions from our roads, as we all start to feel the benefits of the transition to a zero-emission future.

“Before electric cars become the norm, we want to take advantage of reduced CO2 emissions today.

“This small switch to petrol containing bioethanol at 10% will help drivers across country reduce the environmental impact of every journey.”

The E10 blend is already used in other countries such as Belgium, Finland, France and Germany.

Robin Wright, secretary general of environmental campaign groups ePURE, said: “Displacing 10% of Europe’s petrol with ethanol through E10 fuel, a fuel widely available in France, Finland and Germany, would reduce greenhouse gas emissions from petrol vehicles by over 6%.

“But more ambition and greater use of ethanol is needed. Brazil currently mixes its petrol with up to 28% ethanol, so why not Europe?”

Finland is leading the way in Europe. E10 fuel has increased its share of petrol sold each year since it was introduced at the beginning of 2011, with the Finnish Petroleum and Biofuels Association reporting a 63% share in 2015.

E10 petrol is expected to begin appearing at forecourts in September 2021, and this news story carries full details.

While we wait for the arrival of E10 petrol in the UK, drivers are advised to take care when filling up with fuel in France, Germany or Finland. Although the pumps are clearly labelled, it’s important to double-check before filling up.