E10 fuel has arrived - here's what you need to know about the new 'standard' unleaded
E10 petrol has today become the 'standard' type of unleaded being sold at forecourts across the country.
The greener fuel has been introduced in a bid by government to reduce vehicle emissions as part of its wider efforts to hit its decarbonisation targets.
But while E10 petrol will cut CO2 outputs from road transport, there are some drawbacks.
Experts have warned that not all cars on Britain's roads can use it, it is expected to make your vehicle less efficient and it will cost every motorists more - if just fractionally - in fuel bills.
Here's everything you need to know about the switchover to E10 fuel from this month.
What's E10 fuel made from and how does it differ?
The name 'E10' is a reference to the ethanol - or bioethanol - mix in the fuel.
In the case of E10, that is 10 per cent, up from a 5 per cent mix from E5 petrol that's been supplied at forecourts for years.
Simply put, the higher the ethanol mix, the greener the fuel.
That's because the bioethanol content is an alcohol-based product created from the fermentation of a range of plants including sugarcane, cassava and hemp, as well as grains, potato and waste wood.
Technically speaking, this makes any petrol consisting of a bioethanol mix partially 'atmospherically carbon-neutral' because the plants have absorbed more carbon dioxide while growing than what is released into the air during fuel production and combustion.
While ministers will argue that this - in theory - offsets greenhouse gas emissions, there is much debate about by how much.
Materials needed for the higher concentration of bioethanol in E10 will be produced and refined in the UK.
It's introduction is said to have generated up to 100 jobs in the North East, with AB Sugar's Vivergo plant set to reopen, and production due to increase at existing biofuel plants such as Ensus.
Why is E10 being introduced and what are the benefits?
MPs claim the introduction of E10 petrol will cut CO2 emissions by 750,000 tonnes a year.
That's equivalent to taking 350,000 cars off the road today - or every motor registered in North Yorkshire.
Transport Secretary Grant Shapps said the 'small switch' to E10 petrol will 'help drivers across the country reduce the environmental impact of every journey, as we build back greener'.
Doubling the renewable bioethanol mix to 10 per cent also means less fossil fuel is needed in unleaded, which eases the demand on reserves and has environmental benefits.
Are all petrol-powered vehicles able to run on E10?
Unfortunately not - and its use can result in long-lasting damage to engine components.
'E10' refers to the percentage of ethanol mix in petrol. Until now, unleaded has been a 5% mix but has been doubled by as part of efforts to cut road transport emissions
It is estimated that between 600,000 and 700,000 older petrol vehicles on our roads in 2021 are not compatible with E10.
MPs say the vast majority of these will be classic cars owned by enthusiasts who are already using fuel additives to protect their engines from modern fuel.
There are more than one million classic vehicles on the road in the UK with half of them being cars, records from 2016 suggest.
However, E10 could also be destructive to vehicles built in the last 20 years.
The general rule of thumb is that any car registered before 2002 could be at risk if they use E10 petrol and should be checked for compatibility.
That said, only since 2011 has it been a rule for all new cars sold to be able to run on E10. If you have a vehicle older than 2011, it's worth verifying if the greener fuel is recommended for your motor.
'Over 98 per cent of petrol cars in the UK can run perfectly well on E10, but some older models, classic cars and motorcycles shouldn't use it,' according to AA technical specialist, Greg Carter.
How do I find out if my car, van or motorcycle is compatible with E10 petrol?
You can find out if your car is safe to use it by visiting the Government's online checker tool.
A survey of 1,450 drivers this week by the RAC found that more than a quarter of owners (27 per cent) are yet to check whether their car is compatible with new E10 petrol, with a similar proportion (24 per cent) unaware that the new fuel is being introduced at all.
Drivers are also advised to contact their car's manufacturer if they are in any doubt or have concerns.
As the RAC points out, 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.'
Skoda has made public that its current models are fully compatible with the E10 fuel as well as all its cars dating back to 2001.
The Government has created an E10 online checker tool for motorists to clarify if their petrol vehicle is eligible to use the greener unleaded. You simply need to follow the prompts to enter details about your car to understand if it is compliant
What damage could E10 petrol cause to non-compliant vehicles?
Filling an incompatible car with E10 can cause a variety of issues in older vehicles, experts have warned.
Simon Williams, fuel spokesman at the RAC said: 'Owners of classic cars need to be particularly careful not to fill up with E10 and then leave it sat in the tank for long periods, as this will likely lead to expensive damaged seals, plastics and metals.'
To understand the implications in more detail, we spoke to classic car insurer Hagerty.
John Mayhead told us: 'Because ethanol is hygroscopic, it absorbs water from the atmosphere. And that water, in turn, finds its way into your car.
'This can lead to condensation in fuel tanks, fuel lines and carburettors and cause corrosion in brass, copper, lead, tin and zinc components.
'As ethanol is also a solvent it can eat through rubber, plastic and fibreglass, so hoses and seals are likely to perish more quickly because of the higher concentration of ethanol in E10.'
Even Department for Transport tests have identified resulting damage to classic by E10 petrol.
Degradation to fuel hoses, seals and rubber components, blocked fuel filters, damaged fuel pumps, corroded carbs, blocked injectors and corrosion in fuel tanks have all been acknowledged in official documents.
Owners of classic cars are urged to fill-up with super grade unleaded to avoid causing damage to their vehicles that aren't compliant to use fuels with ethanol in them
However, experts at the Historic and Classic Vehicles Alliance (HCVA) - a campaign group setup this year to lobby government to protect classic cars - said many of the concerns about damage caused to older models has been blown out of proportion.
Malcolm McKay director at the HCVA told This is Money: 'It [E10] is a danger if you have deteriorating, incompatible components in your fuel system, but it isn't the end of the world: Brazilian historic vehicles have been running on 25 per cent bioethanol since the 1970s.'
He went on to add: 'Some elastomers, plastics and composite materials used in pre-1996 car fuel systems are not compatible with petrol containing ethanol: it will gradually dissolve them.
'Cork, shellac, glassfibre-reinforced polyester and epoxy resins, nylon and polyurethane are on the 'unsuitable' list.
'Replacement with compatible materials is advised: paper, leather, Teflon, polyethylene and polypropylene are on the 'OK' list.
'If any components in your fuel system are already old and deteriorating, ethanol will find them and accelerate the deterioration – to the point where you could rapidly have running problems and even leaks that could start a fire.
'It's also worth noting that some fuel tank lining products used in the past to coat the inside of pinholed fuel tanks are not compatible with ethanol and cases have been reported of these breaking down, leaking and blocking fuel lines. New lining products are available which are resistant to ethanol.
'Long-term storage of ethanol petrol can lead to corrosion in metal parts of fuel systems, as the ethanol element can absorb moisture if left in the system for a long time, such as over winter, in a humid atmosphere.'
If E10 petrol is greener, will it make my car more frugal than when it ran on E5?
No, because E10 will ultimately burn quicker than E5 due to the higher concentration of ethanol in the mix.
This means drivers who cover above average mileage each year could need to visit filling stations more frequently than before.
In its impact assessment published last year, the Government stated: 'Introducing E10 will add to fuel costs paid by motorists. Moving from E5 to E10 is estimated to reduce pump price petrol costs by 0.2 pence per litre.
'However, as the energy content of the fuel will also decrease, motorists will have to buy more litres of fuel.
'Overall fuel costs for petrol cars are therefore estimated to increase by 1.6 per cent as a result of moving from E5 to E10.'
Will greener E10 petrol make my fuel bills less expensive?
If the switch from E5 to E10 does equates to a 1.6 per cent increase in UK petrol consumption, as MPs have estimated, drivers can expect their annual fuel bills to rise by around £30-a-year (based on current fuel prices) due to the need to fill up more frequently than they have done when using E5.
The RAC warns that a drop in fuel economy is exacerbated in smaller-engined cars.
While you might think this will only count for city cars and superminis, it's important to remember that many medium-size hatchbacks, crossovers and MPVs now feature 1.0-litre turbocharged petrol engines, which ultimately could be among the worst affected by a decline in frugality.
The AA estimates that the Treasury would also see income from fuel duty - the tax on petrol and diesel - increase by £13million-a-month, or £156million per year.
This will help the Government claw back some of the lost income from CO2-based Vehicle Excise Duty now that more tax-free electric vehicles are being used on the road.
If my petrol car isn't compatible with E10, what should I fill up with instead?
Drivers of vehicles that are not able to run on E10 petrol will be forced to fill up with more expensive super grade unleaded, which will be kept at an E5 mix with five per cent bioethanol as the 'default grade' as a safety net for these car owners.
The Department for Transport has previously suggested that E5 fuel might only be available for five years - potentially removed from pumps in September 2026.
After this date, the regulation will be reviewed to decide whether E5 should be retained or if it will fall on owners to turn to specially-created fuel additives for their older machines.
With 'standard' rate petrol now having an E10 mix, drivers of non-compliant cars will have to pay around 12p-a-litre extra to fill up with super grade unleaded, which will remain as E5
What are the cost implications of using alternative petrol to E10?
Super unleaded - like BP's Ultimate and Shell's V Power - is far more expensive than conventional, lower-octane, petrol.
It is currently priced in the UK at an average of 147.5p-a-litre compared to 135.4p for standard petrol (based on current fuel prices at the time of publishing).
To fill a 55-litre fuel tank, you're looking at paying an extra £6.66 each time you fill up a car that can't run on E10.
The typical motorist fills up 24 times a year, meaning annual bills are to rise by £160 for those with cars not compatible with E10.
Is E10 compulsory as standard petrol across the whole of the UK from September?
While it is expected that most forecourts in England, Scotland and Wales will switch to E10 from September, there are some exceptions to the rule.
Most notably smaller, rural filling stations will be allowed to continue selling standard E5 where there's limited supply of the alternative E5 super unleaded.
In Northern Ireland, the introduction of E10 is expected to take place in early 2022, subject to approval by the UK Government.
Filling stations have been displaying posters at their forecourts and handing out flyers to drivers to inform them about the switch from E5 to E10 petrol from 1 September
What are petrol stations doing to educate drivers about the introduction of E10 petrol?
Filling stations have in the months building up to 1 September been working with the DfT to inform motorists about the transition from E5 to E10 standard unleaded, including a poster campaign and relabelling the pumps to say 'E10'.
Gordon Balmer, executive director at the Petrol Retailers Association (PRA), told This is Money: 'We have flyers that motorists can take away that explains the introduction of E10.
'If drivers are unsure about if there vehicle can't take E10 they can use the vehicle checking website that is on the posters and flyers.'
What should I do if I accidentally pump E10 petrol into my car?
While there have been alarming warning about the long-term damage E10 can cause to classic cars, breakdown providers have issued a more relaxed approach about what drivers should do if they accidentally fill up their non-compliant vehicle with the new greener unleaded.
The AA's instruction is very clear: 'Don't panic.'
It adds: 'Engines that aren't compatible with the fuel will not sustain any damage from short term use. Simply fill up with E5 (super) once there is room in the tank and continue to use the correct fuel on subsequent fill ups.
'Unlike filling a petrol car with diesel (or vice-versa), there is no need to have the fuel drained.'
Simon Williams from the RAC says similar. 'People who fill up a non-compliant car with E10 don't need to panic. They shouldn't suffer any lasting damage to their vehicle as long as they put the correct fuel in as soon as possible – when around a third to half the tank is used.
'While using up the fuel they may, however, experience a little poor cold starting and rough running.'
Further RAC advice says that using E10 may cause some pre-detonation - or 'pinking' - though a one-off case shouldn't require the tank to be drained and it is 'highly unlikely' to prevent an engine running at all.
To date, E10 is currently available in 14 EU countries. These are: Belgium, Bulgaria, Denmark, Estonia, Finland, France, Germany, Hungary, Latvia, Lithuania, Luxembourg, the Netherlands, Romania and Slovakia
Is E10 petrol used anywhere outside the UK already?
Yes, and plenty of locations.
In the US, for instance, gasoline has contained either 10 per cent or 15 per cent ethanol since 2012.
And it has been introduced closer to home, with E10 arriving in France in 2009, then Germany and Finland in 2011.
To date, it is currently available in 14 EU countries, including those already mentioned. They are: Belgium, Bulgaria, Denmark, Estonia, Hungary, Latvia, Lithuania, Luxembourg, the Netherlands, Romania and Slovakia.
This is Money asked Gordon Balmer from the PRA if there had been any reports of serious issues for motorists and their vehicles when other nations transitioned to E10 petrol.
He told us: 'We haven't heard anything from any of our other compatriots in the oil industry. As far as we are aware, it is working okay.'
Can I use E10 petrol in my lawnmower?
The AA has warned that owners of petrol-powered lawnmowers should steer clear of E10 petrol and - from this month onwards - only buy super unleaded for their garden equipment.
This is also the case for petrol chainsaws, shredders, wood chippers and generators.
'Petrol powered garden machinery and generators are also likely not to be compatible, so these should use super unleaded after September,' says its technical specialist, Greg Carter.
The AA says those with petrol-powered garden equipment, such as lawnmowers, should avoid E10 petrol and instead use super grade E5
Will diesel's fuel mix be changed like petrol?
The Government points out that diesel already contains up to seven per cent of a renewable substance called 'biodiesel', which all diesel cars are compatible with.