This all started when Avia, one of Germany's largest gasoline distributors, announced that E10 was going to be available at most of its fuel stations in the country. According to Avia, the use of E10 allows motorists to reduce their net CO2 emissions without any effort on their part. For a car that produces 220 g of CO2, this means that E10 saves 15 grams because ethanol is a renewable source (of course, they don't mention how that ethanol was made, but let's assume it was "sustainable").
E10 also costs 3 cents per liter less than gasoline. Current prices in Germany are about 1.41 EUR/l (if you know that a gallon is 3.785 l and that 1 EUR is currently about $1.45 US, that makes $7.74 per gallon), so every little bit helps. E10's performance is almost equal to regular gasoline and most engines need no modification to burn it.
[Source: Auto-News Germany]