A properly designed ethanol engine should be more powerful and use less fuel than a comparable Petrol/Gasoline engine. Most Governments subsidise any bio-fuel’s purchase or use, The UK government will refund the duty up to 25000l per year you would have used so using it can be very cheap. We’re in the throws of climate change too there’s no doubt about that. Whether it’s our fault doesn’t matter, we’ll be the ones experiencing the effects. Government's need to show they are doing something. Internal combustion engines are more thermodynamically efficiency the higher the compression an engine is. Not only is ethanol carbon negative it is higher octane than pump petrol and will if used in a high compression engine be much more powerful, economical and thermodynamically efficient. So it can be a better motor fuel. If you’re green you can feel good about saving the world, if you’re not you can have the personal satisfaction of buying a better motor fuel.
All modern S.I. engines start with settings remembered in the ECU, settings to start the engine using petrol easily. Immediately it fires it continues running with feedback from the sensors. ECU's do accommodate for wear in the moving parts, but they're actually programmed to keep the engine in the most economical and powerful state of tune with petrol. Unfortunately some cars using 100% petrol wouldn't pass. What I'd like is that if all cars would be able to use ethanol, petrol or actually any proportion of each so the driver could actually fill up with whatever was handiest, but that's a problem because ethanol and petrol have so different optimal compressions. At the moment the only way to optimise an engine for both ethanol and gasoline or any mixture would be to have a turbo at full chat for ethanol and off for petrol.
Most Governments know that burning fossil fuel is a major cause of climate change and they've all got a duty of care, that's why all the petrol for sale nearly everywhere has some ethanol in it, that's also why Briton has finally put some bio-fuel duty rebates in place. And even the US has finally ratified the G8 accords to phase out fossil fuel use. Essentially anyone in the UK can get a duty rebate it just has to be a 100% bio-fuel it CAN BE LIGHT OIL (used in a spark ignition engine) or HEAVY OIL (used in a pressure ignition engine) and you must have been charged some road duty for it. The problem is buying 100% bio-fuel is difficult, the oil companies have no reason them sell them, none of the price would actually be for them. The government isn't advertising it (why would they, it would cost them revenue). The 25,000L/year allowance is designed to be just what a private individual would use for personal use.