Currently reading: New E10 fuel could reduce a car's economy by 10 per cent
A real-world study by What Car? suggests the government's plans to introduce new fuel could hit motorists in the pocket
2 mins read
6 February 2014

The introduction of new E10 fuel could increase motorists' fuel consumption by more than 10 per cent. The new fuel, which contains 10 per cent bioethanol, will be rolled out across the UK as part of the government’s commitment to reducing emissions.

But real-world testing by What Car? magazine found that vehicles running on E10 are less efficient than the current E5 (up to five per cent bioethanol) blend of fuel across every engine type tested. This means cars have to use more of the new fuel, costing drivers much more each year.

What Car? tested E10 against pure unleaded using a Dacia Sandero, Hyundai i30, Toyota Prius+ and a Mini Paceman. The Sandero registered a 11.5 per cent drop in economy, while the i30’s consumption increased by 9.8 per cent.

CO2 emissions also increased, although the Low Carbon Vehicle Partnership told What Car? that increases would be partially offset by the renewable properties of bioethanol.

The Society of Motor Manufacturers and Traders said that only 92 per cent of UK cars will run on E10, leaving 1.5 million petrol-powered vehicles at risk of not being able to use the fuel.

According to What Car?, the fuel had previously only been tested in laboratory conditions and the potential impact on fuel economy and CO2 emissions had not been communicated to motorists.

The fuel is expected to be introduced to the UK market later this year as part of the government’s commitment to reducing greenhouse gas emissions and conforming to the EU’s Renewable Energy Directive. This requires 10 per cent of road transport energy to be from renewable sources by 2020.

What Car? editor-in-chief, Chas Hallett, called on the government to carry out in-depth tests to understand the financial impact on drivers. He said: “The US Environmental Protection Agency estimates that the detrimental effect of E10 on fuel economy is between three and four per cent, but even our small sample of tests proves otherwise.

“To lead consumers into E10 without fully communicating the significant impact on fuel economy, particularly for drivers least able to absorb the extra costs, is irresponsible.”

For an explanation of how What Car? carries out True MPG testing, click here.


Find an Autocar review

Read our review

Car review
Dacia Sandero

The Sandero represents basic motoring done well, for those who really want it

Join the debate


6 February 2014
I had no idea this was being rolled out and these findings concern me. The sceptic in me wonders if this is a conspiracy to increase petrol consumption to bolster the governments coffers through tax. I also question the environmental basis for this if CO2 emissions will increase, but also on a social level, have we enough land in the world to grow our fuel when there are people without enough food to eat. Electric cars may not be perfect, but I very much look forward to the day when they become viable for my needs.

6 February 2014
Unfortunately What Car doesn't give any details of how its tests were conducted, only on the results achieved. I suspect that the tests may not have been very scientific, so I'm sceptical about these findings. (for example the picture shows tests being conducted on a wet road, known to increase consumption. So was the track uniformly and constantly wet - and what about other variables?).
On the other hand, this does suggest that more and proper testing is needed before this fuel is released to market.

6 February 2014
Of course it will cost us more, the Govt have identified a huge hole in tax revenue because we are driving less and buying smaller more efficient cars, you can bet your last pound that there will not be a reduction in fuel tax or the illegal double tax of VAT levied on fuel tax to compensate.

6 February 2014
... and none of my cars (Fiat 500C, Porsche Cayman 987, Audi A4) showed any increase in consumption.
We had the same rumors over here prior to the introduction of E10 and I do not know a single person reporting it being less efficient than E5.

6 February 2014
I wasn't aware of this, will definitely be paying attention over the next few months. Would have thought it pretty easy to conduct an economy test though... take two brand new cars, a tankful of E5 in one, a tankful of E10 in the other and drive the two of them in convoy. You don't need a degree in rocket science to work out the real world mpg differences.
I just hope whoever does work out the mpg data isn't the same bloke who claimed my Focus can average 68mpg!

6 February 2014
there are of course potential issues for classic motorists in terms of material compatibility, and exacerbated vapour lock. Since the E %content won't be advertised on the pump, it will be hard to know what you are putting in.
Those interested should keep an eye on the FBHVC site. I understand that Super Unleaded remains at E5 for the moment.

6 February 2014
Our government is not interested in meeting renewable energy targets, as evidenced by their drive to force through licensing of the oil & gas industry to use unconventional techniques such as fracking & CBM.
More evidence can be found in the lack of support for wind turbines, offshore wave hub generators as well as other new technologies which could ensure we are less dependant on fossil fuels and importing fuel from overseas. Anything that ensures we burn more fuel such as speed humps & so called traffic calming measures is sanctioned by our government, who have no incentive to encourage us to burn less fuel as the motorist is just a cash cow for the treasury.
Has the public woken up to the fact that we are the ones who have to constantly cut back & use less energy in the home etc while it is clearly OK for our military to sail & fly half way round the world in order to secure more oil. How much Co2 do we as a nation spew out fighting this never ending war on terror.?

6 February 2014
Obviously there is an increase in consumption if they are driving with all that equipment/bike rack on the back of the vehicle. Like mentioned above - how do we know this is a fair test without actually having information!?

6 February 2014
E5 ... E10 ... E100!!! ... It's all a moot point given that China is pumping out CO2 like there's no tomorrow ... That said, I'm certain of the big smile on the Government's face at another wheeze to wring more tax money from the motorist ...

6 February 2014
I used this on my brand new (had done about 700 miles) Fiat 500 TwinAir last summer when I drove across France. Didn't realise what I had put in the car until it was too late and the tank was full.

I panicked and was terrified the car wouldn't start. Needless to say the car then proceeded across France just as happy as 95' petrol.

A non issue.


Add your comment

Log in or register to post comments

Find an Autocar car review