There's a world of difference between assuing the worst and making it up as you go along Peter.
I doubt we need a barrel of Petroleum to make a barrel of Ethanol. Transport, which is the only all oil input, is about five percent of a gallon of Ethanol's energy input, and lets assume half of all on farm FF use is oil, although it's
technically closer to 20-30%. So for Ethanol from corn, the most energy intensive form of Ethanol out there, oil accounts for about 10% of the energy inputs for Ethanol. A gallon of Ethanol has about 76,000Btu, so we need about 8,000Btu of oil per gallon of Ethanol. A gallon of oil has a little less than twice as much energy, so there's no way we need a whole barrel of oil to make a barrel of Ethanol.
I'm not going to begrudge the point that it takes oil to get oil, specifically gasoline, diesel, keroscene, etc... to get more oil, and so on. But that doesn't mean it's O.K. to make stuff up. Along those lines it isn't just biofuels and unconventional oil that require oil to get, conventional oil requires a lot of oil based products to make, mostly oil based fuels (diesel/bunker) needed for
distribution of the oil and it's refined products. If you're really serious about all the oil that's being counted twice, just look up te energy inputs needed for refining and extraction (almost everything there is natural gas, a small amount of electricity, and way less oil), then compare that to gasoline's GHG emissions from production to figure out how much energy distribution, which is primarily oil based, needs. Multiply that by however much conventional crude we have. Do the same for Ethanol and stuff like tar sands adding the extra oil needed for stuff like huge trucks for mining, and you'll get the total amount of oil that's counted twice so to speak. Ignore any financial data that could be clouded by subsidies and just focus on the the energy aspect. It's more or less energy returned on oil energy invested as opposed to all energy invested.
$this->bbcode_second_pass_quote('Professor Membrane', ' ')Not now son, I'm making ... TOAST!