http://en.wikipedia.org/wiki/E10_fuel
E10, sometimes called gasohol, is a fuel mixture of 10% ethanol and 90% gasoline that can be used in the internal combustion engines of most modern automobiles. According to the Philippine Department of Energy, the use of not more than a 10% ethanol-gasoline mixture is not harmful to cars' fuel systems. On October 27, 2006, though, the Federal Aviation Administration published their Special Airworthiness Information Bulletin - Automobile gasoline containing alcohol (Ethanol or Methanol) is not allowed to be used in aircraft.
It has been introduced nationwide in Thailand, and has replaced high octane pure gasoline in that country in 2007. It is also commonly available in the Midwestern United States. It is the only type of gasoline (besides aviation grade fuels) allowed to be sold in the states of Connecticut and Minnesota, along with E85.[dubious – discuss] About half of the gasoline used in the U.S. contains ethanol. As of spring of 2006, due to the phasing out of MTBE as a gasoline additive, E10 use has increased throughout the United States.
Similar blends include E5 and E7. These concentrations are generally safe for recent engines that run on pure gasoline. Some regions and municipalities mandate that the locally-sold fuels contain limited amounts of ethanol. One way to measure alternative fuels in the US is the "gasoline-equivalent gallons" (GEG). In 2002, the U.S. used as fuel an amount of ethanol equal to 137 petajoules (PJ), the energy of 1.13 billion US gallons (4.28 GL) of gasoline. This was less than 1% of the total fuel used that year.
The Tesco chain of supermarkets in the UK have started selling an E5 brand of gasoline marketed as 99 RON super-unleaded. Price-wise it is cheaper than the other two forms of high-octane unleaded on the market, Shell's V-Power (99 RON) and BP's Ultimate (97 RON).
Many petrol stations throughout Australia are now also selling E10, typically at a few cents cheaper per litre than regular unleaded. It is more commonly found throughout the state of Queensland due to its large sugar cane farming regions. The use of E10 is also subsidised by the Queensland government. Some Shell service stations are also selling a 100 RON E5 blend called V-Power Racing (as opposed to the normal ethanol-free 98 RON V-Power). This is typically a fair bit more expensive, approximately 17 cents dearer than regular unleaded.
In Sweden, all 95-octane gasoline is in fact E5, while the status of the 98-octane fuel is unclear for the moment. The product data sheets of the major fuel chains do not clearly state anything related to ethanol contents of the 98-octane gasoline. In the early-mid nineties some fuel chains marketed E10. The EU mandates that until 2010 E10 has to be reintroduced for 95 RON fuel.
