What is E10 petrol and should you use it?

The government wants to standardise E10 petrol in order to reduce CO2 emissions. However, the fuel could cause problems if used in older cars.

Consultation begins on standardisation of E10 petrol

The government has started a consultation on introducing E10 petrol as the standard petrol grade across the UK. The idea is to replace the E5 fuel used now. We explain what E10 fuel is, along with the pros and cons of standardising it.

The difference between E10 and E5 petrol is quite simple. The numbers refer to the percentage content of bioethanol in the fuel. E5 contains five percent and E10 contains 10 percent. Last year, normal petrol and diesel were renamed at the pumps, to E5 and B7, to inform motorists of their biofuel content.

Why the proposed switch to E10 petrol?

E10 petrol to reduce emissions

Standardising E10 appeals to the government, because it would help reduce CO2 emissions of petrol-powered cars on UK roads. It’s claimed the benefit would be equal to taking 350,000 cars off the road. The Department for Transport says CO2 emissions will be cut by around 750,000 tonnes a year. 

This would be a big help in reaching the UK’s climate change targets, and its ‘Renewable Transport Fuel Obligation’. The latter is the promise that 9.75 percent of all transport fuels will be from renewable sources by the end of this year. 

What are the problems with E10 fuel?

Volkswagen Beetle

The worry is that some older cars suffer when you fill them with E10 petrol. The bioethanol is believed to be corrosive to many components, including hoses, seals, plastics, gaskets and even certain metals in the fuel system.

This can damage fuel pumps, injectors, pressure regulators, carburettors and fuel tanks. And it’s worth noting that ‘older cars’ doesn’t necessarily mean classics. Many regular used cars could sustain damage if filled with E10.

When asked in parliament what assessment she has made of the issues with E10 for older vehicles, Rachel Maclean, Parliamentary Under Secretary (DFT) said: “One of the main barriers to introducing E10 has been vehicle compatibility. Currently, around 95 percent of petrol cars used in the UK can use E10, but around 700,000 are not warranted by their manufacturers to use E10.”

Jaguar E-type

“This number is expected to decrease as vehicles come to the end of their life. However, some classic and cherished vehicles that are not advised to use E10 will remain in use. The prolonged use of E10 fuel in those older and classic vehicles not under manufacturer warranty can cause corrosion of some rubbers and alloys used in the engine and fuel systems. 

“For those vehicles, the department remains committed to ensuring that E5 is retained as a protection grade, if E10 is introduced.”

Moving the CO2 around

Emissions reduction congestion charge zone

A more general issue, highlighted by the Federation of British Historic Vehicle Clubs, is logistics. It’s reported that the only UK refinery for the fuel additive is no longer running. The environmental benefit of the E10 fuel rollout could be negated by the emissions cost from shipping.

The FBHVC has committed to pressing for the so-called ‘protection grade’ being made available, alongside the rollout of E10, in the latest consultation. 

The RAC’s view on ‘protection grade’

fuel prices drop coronavirus

The RAC has raised concerns about the retention of E5 as a ‘protection grade’ of petrol. While possibly adequate for niche and leisure classic owners, it could put a strain on low-income drivers.

This fuel could be hard to find and more expensive – for drivers who really don’t need added cost. Furthermore, fuel forecourts may not have the capacity to incorporate both grades. That could further affect rural low-income motorists.


“Everybody agrees that steps must be taken to reduce emissions from road transport. However, introducing E10 as the standard petrol will pose some challenges,” said RAC fuel spokesman Simon Williams.

“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.”

Incentivising the use of E10

oil price drops should mean petrol savings for motorists says RAC

Auto Logistic Solutions, an incident management company, has called for the insurance industry to use incentives in policies to encourage drivers’ use of E10. This could mean reduced premiums.

It also wants incentives for drivers to scrap their older cars and buy newer E10-compatible models. This could be a solution, at least in part, to the alienation of low-income drivers the RAC has highlighted.

parking fines petrol station

“We are calling for the motor insurance industry to implement incentives into their policies and encourage drivers to use E10 fuel,” said Kyle Harris, managing director at Auto Logistic Solutions.

“By offering a reduced premium, drivers will be incentivised to opt for the lower octane fuel. It would [also] be beneficial to provide an incentive to drivers and make it financially viable to scrap their older car.” 

Getting the word out on E10

petrol pump

Then there’s the issue of publicity. Drivers will need to be made aware of the changes to fuel grades. The RAC has also recommended that a guide on exactly which cars will be affected should be published.

“It is also vital that owners of affected vehicles are aware of the changes,” Williams continued. 

“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.”

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Ethan Jupp
I'm Content Editor at MR. Road trips music and movies are my vices. Perennially stuck between French hot hatches and Australian muscle cars.


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