E10 petrol was introduced across the UK from September 2021. However, many drivers remain unaware of the change – and up to 600,000 cars on British roads aren’t compatible with it.
In this guide, we explain what E10 is – and examine its pros and cons.
The difference between the old E5 and current E10 grades of petrol is quite simple. The numbers refer to the percentage of bioethanol in the fuel. E5 has five percent and E10 contains 10 percent.
Petrol and diesel had already been renamed at the pumps before the switchover, to E5 and B7, to inform motorists of their biofuel content.
Why the switch to E10 petrol?
The main reason for bringing in E10 is to reduce carbon dioxide (CO2) emissions. The Department for Transport says CO2 output has been cut by around 750,000 tonnes a year.
This is around two percent less CO2 per car, or equivalent to taking 350,000 cars off UK roads.
In conjunction with the gradual switchover to electric cars, the move will help achieve Britain’s climate change targets, and meet the government’s Renewable Transport Fuel Obligation. The latter is designed to encourage the use of biofuels.
What are the problems with E10 fuel?
The worry is that some older cars can suffer when filled with E10 petrol. The bioethanol, which is created from fermented plants, can be corrosive to certain components. These include hoses, seals, plastics, gaskets and even certain metals in the fuel system.
The process can damage fuel pumps, injectors, pressure regulators, carburettors and fuel tanks. And it’s worth noting that ‘older’ doesn’t necessarily mean classic cars. Many more recent vehicles could sustain damage if filled with E10.
When asked in parliament what assessment she had 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.”
“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.”
On the latter point, the official government statement says: ‘We’ll also require the higher-octane Super grade to remain E5 to provide protection for owners of older vehicles.’
So drivers still have the option of E5 fuel, albeit at a significantly higher cost (typically around 12p more per litre than standard unleaded).
Moving the CO2 around
The RAC has raised concerns about the retention of E5 as a ‘protection grade’ of petrol. While perhaps less of an issue for classic car owners, its higher cost could put a strain on low-income drivers.
Furthermore, fuel station forecourts may not have the capacity to incorporate both E5 and E10 grades. That could further affect motorists, particularly in rural areas.
A more general issue, highlighted by the Federation of British Historic Vehicle Clubs, is logistics. It was reported that the only UK refinery for the E10 fuel additive is no longer running. The environmental benefit of the E10 rollout could thus be negated by the emissions cost from shipping.
Getting the word out about E10
Drivers of older cars clearly need to be aware of the change to fuel grades. If you’re part of a classic car club, it’s an issue worth highlighting.
Helpfully, ou can check if your car is compatible with E10 fuel by using the tool on the official GOV.UK website.
Finally, some words of reassurance from RAC fuel spokesperson, Simon Williams: “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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