What is better, 60mpg on gas, or 30mpg on E85?

[brpeterson]

My dad is going to be purchasing a new car in the next month or so and he is interested in the Insight, HCH and Prius. Please disregard money as a factor in answering this question: What has less environmental impact, and Insight (60mpg) vs. a 4cyl. Malibu (guess 30mpg or so on E85)? If the logic is correct, and E85 is environmentally begin,an E85 Malibu gets about 200mpgs on gas. A common argument I hear against E85 is that the energy input is only slightly less than the energy output. While this point is important, I wonder if anybody can speak to how much energy it takes to suck oil out of the ground, ship it half-way around the word, and on and on? Thanks

[Dougie]

This is an incredibly complicated question because there are market distortions in all energy supplies--subsidies, taxes, political manipulation, etc. My general understanding is that the current U.S. process for making ethanol from corn is probably only slightly better from an environmental viewpoint than gasoline, due to the need for fertilizer and various diesel inputs (for tractors, trucks, irrigation pumps, etc.) that come from fossil fuel. Ethanol from sugar cane in Brazil is less expensive from the energy viewpoint, but faces tariff barriers in the U.S.

The huge mileage difference between the cars you mention almost certainly overwhelms any advantage E85 might have. It would be better if hybrids could run on E85, but in the meantime I think your most environmentally sound choices are the Prius or the Civic (or, best of all, a second-hand Insight).

[Guillermo]

"What has less environmental impact?"

If the car is driven alot then the car with lower emissions has less environmental impact. Lowest fuel consumption does not mean it has the lowest emissions. 5 speed Insight has the lowest consumption but the CVT Insight has lower emissions. There are brand new gasoline only cars now that have lower emissions then a 5 speed Insight.

[brpeterson]

I guess I don't really know what I mean when I say, "environmental impact" or "emmisions." My thinking is that all modern cars have relatively "clean" exhaust, that catalytic converters do a good job and that carbon is the pollutant most troubling. So, which option creates the least carbon emmision? Can anybody answer this, does burining a gallon of gas, whether in an Insight gettting 90 mpg or a bus getting 10 mpg, release the same amount of CO2?

[b1shmu63]

If it takes .75 gallon of diesel fuel in tractors trucks and heating vats to create 1 gallon of ethanol then the practice of using ethanol is to say the least questionable. Importing it from Brasil where the weather is more suitable makes some sense. Running on ethanol makes sense politically as it subsidizes the farmers. It makes sense from a city pollution perspective and it makes sense from the aspect of reducing MTBE in the environment, which is a potent carcinogen. It will not solve the oil crisis in any way until it is produced from waste products. Heavy cultivation of corn destroys the soil and deprives humanity of food if it is used for fuel.

Pollution ratings of cars do not take into account CO2 production. In that respect the 5 speed Insight is king...still! It is this writer's opinion that climate change brought about by CO2 will make the planet uninhabitable save for insects and desert plants in the near future, but I resect others right to believe the contrary and sincerely hope I'm mistaken.

A gallon of gasoline will produce roughly the same amout of CO2 regardless of how it is burned. Other fuels will produce varying amounts of CO2 depending on their ratio of hydrogen to carbon.