London, England - The British government's introduction of 'greener' petrol to meet EU regulations could cost UK drivers billions of pounds a year and increase harmful CO2 tailpipe emissions.
The move to introduce E10 fuel, which is expected to happen this year, has been branded as "irresponsible" by consumer magazine "What Car?" after it carried out the first real-world tests on the new petrol blend; before then the fuel had only been tested under laboratory conditions.
E10 fuel contains 10 percent bio-ethanol and is being rolled out across the UK as part of the Government's commitment to reducing greenhouse-gas emissions and conforming to the EU's Renewable Energy Directive, which requires 10 percent of road transport energy to be from renewable sources by 2020.
However, the "What Car?" testers discovered that E10 is less efficient than the current E5 (up to 5 percent bio-ethanol) petrol in every engine type they tested, meaning cars have to use more of the new fuel, costing drivers much more each year.
Editor-in-chief Chas Hallett said: "The United States Environmental Protection Agency estimates that the detrimental effect of E10 on fuel economy is between three and four percent, but even our small sample of tests proves otherwise."
The magazine tested E10 against E0 'pure' petrol so it could directly compare its results with thos obtained by the EPA. The cars used were a three-cylinder turbo Dacia Sandero, a naturally aspirated Hyundai i30, a hybrid Toyota Prius and a four-cylinder turbo Mini Paceman.
The Sandero fared worst, returning 11.5 percent higher fuel consumption, while the 74kW i30 was almost as bad, burning 9.8 percent more fuel per 100km on E10.
It's not just fuel-consumption that's affected by the use of E10 - CO2 tailpipe emissions also increased in every vehicle tested, although the Low Carbon Vehicle Partnership asserts that these increases would be partially offset by the renewable properties of bio-ethanol and the fact that the crops used to produce it absorb CO2 while growing.
Overall, the "What Car?" tests suggest that more powerful cars cope better with a higher ethanol content, leaving smaller cars - often bought by drivers on a tighter budget - more severely affected.
Not only that - not every car on the roads will even be able to use the 'green' petrol. The Society of Motor Manufacturers and Traders says that 92 percent of British cars are compatible with E10, but that still leaves about 1.5 million vehicles at risk, and these are more likely to be older vehicles, again likely to be owned by motorists on tighter budgets, who can least afford the extra expense.