Which produces more carbon dioxide CO2 per one horse power: gasoline burning engine or ethanol burning engine?

Ethanol produces more CO2 than gasoline when it is burned. However you do have to look at what gasoline and ethanol are derived from.

Gasoline is derived from fossil fuels. Fossil fuels contain carbon that has been stored for thousands or millions of years. So 100% of the CO2 they emit is basically brand new to the atmosphere.

Ethanol is derived from plants. The carbon in the plants is derived from the CO2 they absorb from the air. So the plants absorb CO2 from the air, then the CO2 is released back into the air when the Ethanol is burned.

So even though Ethanol does release more CO2, the net negative affect of the two fuels is less for ethanol than for gas. The plants used to produce ethanol counter-act the affect of burning ethanol because they absorb CO2. So what is released is no more than what is absorbed. On gasoline, it is 100% newly released CO2 and therefore is normally considered worse for the environment.

Also, I believe gasoline while it does produce less CO2, it does produce more CO. Which is typically considered worse for the environment than CO2.

It makes ZERO difference which one produces more CO2 what does matter though is the fact that ethanol is produced from plants that had absorb existing CO2 from the atmosphere so there is no net gain in CO2 in the atmosphere.

The important thing to keep in mind here that ethanol in the US is produced with as much as 60% fuel from crude oil from the fertilizers used to grow it the combines powered by it to harvest the grain and the trucks that transport it to the processing plant. The processing plant itself runs off the grid so it consumes coal to make ethanol.

Not very environmentally friendly when you take everything in to account. But it is a scam that works well for the politicians

You also forgot to mention that gasoline can be shipped via pipelines from where it is drilled to a central distribution center whereas ethanol cannot be piped and must be carried by truck from the farmland to the distillery and from the distillery to the gasoline mixing station.

Additionally, what do you think farming equipment runs on? You can't get ethanol without filling up the tractors and combines.

All told, ethanol costs more gasoline to produce then it saves by being used.

Not to mention that by legally mandating its use and subsidizing its production, the government has caused a massive price increase in the corn market which has caused a price increase in almost all food products.

Let's assume we found an underground source of ethanol. (It came from a newly discovered coal munching bacteria). That way we are playing with apples and apples.

Ethanol has a lower caloric count per carbon molecule. It is partially oxidized.

But ethanol has a higher octane count (116) which -- for a car designed to run on ethanol -- allows greater compression and consequently, greater power output and efficiency.

So if you are stuck with current internal compression engine design and you specially design for ethanol, then ethanol wins -- but not by much.

If you have a mixed use engine, ethanol loses. (Personal experience -- my car loses gas milage when it has a part ethanol blend)

Ethanol

Gasoline ΔH: 11.3Mcal/kg

Ethanol ΔH: 7.1Mcal/kg

http://en.wikipedia.org/wiki/Heat_of_combustion

Your average gas has ~7 carbon per molecule.

http://www.elmhurst.edu/~chm/vchembook/514gasoline...

since in practice gasoline contains chains from 5 to 10 carbons long.

Thus the ratio of carbon by weight of gas is then on average 84% by weight (say it's all heptane for the argument) In ethanonl it's 52%

The ratio of mass to produce the same amount of heat of gas to ethanol is 7.1/11.3 by weight. The ratio of carbon in gas to ethanol is 84/52 by weight. Thus the energy/carbon ratio is

7.1/11.3*84/52 = 1.02 as expected.

This means that on an energy/CO2 basis, fuel is fuel. You need more ethanol to get the same amount of energy as gasoline by weight, but that is simply because ethanol contains less carbon by weight than gasoline.

Per horsepower then, the same amount of CO2 is released.

In the end, gasoline makes a more practical fuel, simply because you need less of it.

Ethanol. Ethanol is produced from plants, which pull carbon dioxide from the atmosphere. Therefore burning ethanol creates no net gain in atmospheric carbon dioxide. Gasoline is produced from petroleum, which has been buried miles below the earth's surface for millions of years. Burning gasoline does increase atmospheric carbon dioxide.

Depends on the source of ethanol. Corn based, yes. However, switchgrass based ethanol is a different story.

Why are you giving up on green solutions after one try and trying to move forward in the 21st century with a 19th century energy source?

Global warming is not a scam. In ten years mankind will have developed fuel technology that will make ethanol look old.

And if McBush / Failin would have won it would have been ten years before the world saw a drop of oil.

There's a science section you know; i think you posting this for the politics-elections people to answer says a lot about your intelligence