Comments on: Cost of Ethanol Production

Question: Cost of Ethanol Production

Raybun — Fri, 02 Sep 2005 18:01:48 -0800

How much energy from oil goes into the production of 1 gallon of ethanol? References would be appreciated.

By: atchafalaya

atchafalaya — Fri, 02 Sep 2005 20:11:52 -0800

Google Michael Wang. He just wrote a nice comparison that showed ethanol was better than petroleum. Cellulosic ethanol, using wood waste and stuff, was even better than crop-based ethanol. Google that too. I saw his presentation on CSPAN.

By: 517

517 — Fri, 02 Sep 2005 20:25:21 -0800

It depends on who you ask. 2 years ago there was a paper on the internet published by the USDA in the late '90s that stated that the energy balance was close to null. I can no longer find that paper.

Instead I find this but that should be read with this in mind. The truth is ethanol has always been a farm subsidy. Any energy gain it produces is purely serendipitous.

See this also.

By: alms

alms — Fri, 02 Sep 2005 20:43:58 -0800

"There is just no energy benefit to using plant biomass for liquid fuel," says David Pimentel, professor of ecology and agriculture at Cornell. "These strategies are not sustainable."

Pimentel and Tad W. Patzek, professor of civil and environmental engineering at Berkeley, conducted a detailed analysis of the energy input-yield ratios of producing ethanol from corn, switch grass and wood biomass as well as for producing biodiesel from soybean and sunflower plants.

Their report is published in Natural Resources Research (Vol. 14:1, 65-76). In terms of energy output compared with energy input for ethanol production, the study found that: corn requires 29 percent more fossil energy than the fuel produced; switch grass requires 45 percent more fossil energy than the fuel produced; and wood biomass requires 57 percent more fossil energy than the fuel produced.

In terms of energy output compared with the energy input for biodiesel production, the study found that: soybean plants requires 27 percent more fossil energy than the fuel produced, and sunflower plants requires 118 percent more fossil energy than the fuel produced.

By: alms

alms — Fri, 02 Sep 2005 20:46:04 -0800

But then again, The National Resources Defense Council recently noted that the prevailing finding of major studies analyzing ethanol's energy balance, including those by U.S. Department of Agriculture, the Argonne National Laboratory and Michigan State University, was that ethanol contains 30 percent more energy than the fossil fuels involved in its production.

By: mathowie

mathowie — Fri, 02 Sep 2005 20:58:09 -0800

I did a search on your entire question, and this is the second result, talking about the energy balance of ethanol production.

By: delmoi

delmoi — Fri, 02 Sep 2005 23:02:34 -0800

How much energy from oil goes into the production of 1 gallon of ethanol? References would be appreciated.

Well, none, if you don't start with energy from oil to begin with.

Just pointing that out. Also.

The energy balance of ethanol is found by taking the amount of energy contained in a gallon of ethanol (roughly 76,000 Btu) and subtracting the amount of energy that goes into producing a gallon of ethanol. Critics of ethanol have argued that it has a negative net energy value (NEV), meaning that ethanol requires more energy to make than it actually produces. However, over the years numerous studies have shown that ethanol does indeed have a positive NEV. Most recently, a 2002 study by the US Department of Agriculture that accounts for gasoline and diesel fuel use, fertilizers and a variety of other energy inputs in the production, concluded that the energy balance of ethanol is 1.34:1.1 This means that ethanol "yields 34% more energy than it takes to produce it, including growing the corn, harvesting it, transporting it and distilling it into ethanol." These data are consistent with a study by Dr. Bruce Dale, Michigan State University (2002), and a study by Argonne National Laboratory (1999).

By: delmoi

delmoi — Fri, 02 Sep 2005 23:05:11 -0800

Man, if I had a few miillion dolars, I'd start an ethenol farm. Think about it. They pay you subsides to grow the corn, and then you take that corn and sell it to yourself. Then you turn it into ethenol, and get a subsidy on that. Then you take that ethenol and use it to grow more crops. You only make a slight true profit of energy, but get tons and tons of subsidies.

By: JJ86

JJ86 — Sat, 03 Sep 2005 02:48:00 -0800

I'm with delmoi on this. Even if you start with some fossil fuel to begin with, once you have the system producing ethanol, you can switch over to ethanol to power the production. Any refining process requires power to sustain. To deny that is unscientific and political bullshit.

Of course the real problems with ethanol are the need for vast quantities of corn, which are limited. The quantity of resources necessary are not at the same level as the quantities available through fossil resources.

By: anadem

anadem — Sat, 03 Sep 2005 08:48:10 -0800

corn is not very efficient as a source for ethanol
corn: 250 gal/acre
beet: 100 gal/acre
cane: 1200 gal/acre
manioc: 1500 gal/acre
jerusalem artichokes: 1500 g/a
cattails: 2500 g/a

The best current US system has a 6-month rotation of cane and beet.

I have a lot of other useful relevant figures, some with references, from a class i took recently which i can dig up later (or email me)

ADM have a great pilot system combining corn / ethanol / CO2 / fishfarming that produces huge amounts of food and enery from small areas

Don't forget to include the industrial uses of CO2 when calculating the benefits of ethanol.

By: anadem

anadem — Sat, 03 Sep 2005 08:49:02 -0800

oops in the ADM system I missed out the greenhouses that grow lettuce etc and house the fish

By: JJ86

JJ86 — Sat, 03 Sep 2005 10:49:12 -0800

I also thought I heard that hemp was a very good efficient source for biodiesel. Sorry I can't back that up but I guess considering the plant itself that there would be legal stumbling blocks to using it on a large enough scale to make it worthwhile.