I have read that there will be pressure on fuel companies to make E10 (10% ethanol) fuel generally available. I can appreciate that with respect to production, the inclusion of ethanol does reduce the overall carbon dioxide output (CO2 will be removed from the environment in its manufacture). However, it's lower efficiency as a fuel will increase the amount of fuel required. I suspect that one will virtually cancel out the other. How do the figures actually stack up over a range of vehicles?