Ethanol and biodiesel from corn and other crops is not worth the energy

[C1ay]

Turning plants such as corn, soybeans and sunflowers into fuel uses much more energy than the resulting ethanol or biodiesel generates, according to a new Cornell University and University of California-Berkeley study.

 

"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.
  

In assessing inputs, the researchers considered such factors as the energy used in producing the crop (including production of pesticides and fertilizer, running farm machinery and irrigating, grinding and transporting the crop) and in fermenting/distilling the ethanol from the water mix. Although additional costs are incurred, such as federal and state subsidies that are passed on to consumers and the costs associated with environmental pollution or degradation, these figures were not included in the analysis.

 

"The United State desperately needs a liquid fuel replacement for oil in the near future," says Pimentel, "but producing ethanol or biodiesel from plant biomass is going down the wrong road, because you use more energy to produce these fuels than you get out from the combustion of these products."

 

Although Pimentel advocates the use of burning biomass to produce thermal energy (to heat homes, for example), he deplores the use of biomass for liquid fuel. "The government spends more than $3 billion a year to subsidize ethanol production when it does not provide a net energy balance or gain, is not a renewable energy source or an economical fuel. Further, its production and use contribute to air, water and soil pollution and global warming," Pimentel says. He points out that the vast majority of the subsidies do not go to farmers but to large ethanol-producing corporations.

 

"Ethanol production in the United States does not benefit the nation's energy security, its agriculture, economy or the environment," says Pimentel. "Ethanol production requires large fossil energy input, and therefore, it is contributing to oil and natural gas imports and U.S. deficits." He says the country should instead focus its efforts on producing electrical energy from photovoltaic cells, wind power and burning biomass and producing fuel from hydrogen conversion.

 

Source: Cornell University

[Biochemist]

Gee. It doesn't look like the physics or chemistry have changed in the last 50 years. Quite a surprise.

 

Do you wonder how often these analyses have to get published before someone in Washington actually reads them?

[C1ay]

I suppose someone could make a solar still to extract the ethanol from corn. Not that the energy yield would be any better, just as a method to convert solar energy into a form that could be used by the combustion engine without using fossil fuels to do it.

[Biochemist]

I suppose someone could make a solar still to extract the ethanol from corn...

Good thought. That would also get around the transport cost problem, if thewe were small scale units that were used by the folks that actually grew the corn. It would be interesting to see how much of the energy cost was atributed to the fertilizer and herbicides.

[C1ay]

....if thewe were small scale units that were used by the folks that actually grew the corn....

Why? I can envision a solar still the size of a grain silo. I wouldn't light any matches nearby though ;)

[bumab]

Good thought. That would also get around the transport cost problem, if thewe were small scale units that were used by the folks that actually grew the corn. It would be interesting to see how much of the energy cost was atributed to the fertilizer and herbicides.

 

I've heard of several farmers around here doing that, and they have replaced most of their fuel with that source. It's only enough to support their needs, however.

[learnin to learn]

...It's only enough to support their needs, however.

 

(I know very little about this topic) Why is it only enough to support their needs? Is it because they only produce enough to to run their farm? or...

[Lilac]

Um, yeah. If there's no way to distribute any "excess" energy produced, then there's absolutely no reason to produce that excess, so of course the farmers would only produce what they need themselves. A natural limit to production, you might say.

 

The question becomes, if an economically viable means for distribution were put into place, how much more could be produced without straining the farmer's systems?

[Guest FDDoty]

The “new study” by Pimentel and Patzek in Natural Resources Research, Vol 14, (March, 2005) showing negative energy value in all biofuels is even more biased and less scientific than most of what we’ve seen from Pimentel for the past 25 years.

 

Perhaps the biggest technical problem in Patzek’s works is the value used for the fossil energy input in production of fertilizer. This energy requirement has been steadily decreasing over the past 35 years. The theoretical minimum for NH3 is around 25 GJ (HHV) per ton of NH3. The mean for plants built in the 1960s was 75 GJ/t, and for new plants constructed in 1997 it was around 33 GJ/t. The average for all U.S. plants in 1995 was 40 GJ/t, or 11.1 MWh/t, or 17,600 BTU/lb. Patzek (in a 2003 paper) mentions this 1995 U.S. average number, then inflates it (unnecessarily) 10% for transportation and handling. He then jumps to an energy value for urea (which is more energy intensive than ammonia and accounts for about 50% of nitrogen application) from the 1980’s (28,800 BTU/lb), inflates it by 10% for transportation and handling, and applies this number to all fertilizers.

 

A more realistic number for mean fossil energy per pound of fertilizer just 5 years from now is about half of what Patzek assumes. And of course, 20 years from now, it could easily be just 20% of what Patzek assumes if there is aggressive support of production of renewable fertilizers on wind farms.

 

Then there is the question of how much fertilizer is used. Are the reported numbers in pounds of NH3 or pounds of nitrogen? Patzek assumes agricultural reports are always quoting nitrogen fertilizer amounts in nitrogen content, whereas in some cases they were reporting ammonia amounts and nitrogen would be 14/17 as large. He then consistently uses the highest reported fertilization rates from various studies. His phosphorus application rates, for example, are at least 30% above more commonly reported mean rates, which are steadily decreasing.

 

There are similar problems in his analysis of energy required for processing the corn into ethanol, where he relies heavily on data from the 80’s, which he then inflates by 20% to account for the energy required to make the concrete and steel in the ethanol plant (even though the plants may have a 40 year design life). His credits for the value of co-products are unrealistically low by even greater proportions. His analysis of ethanol from cellulose and hemicellulose, based on processes from the 70s and 80s, is not even worthy of comment.

 

Finally, for special effects, Pimentel and Patzek like to report the total energy input, including the solar energy, just after he’s been summing fossil energy input and net energy output in an attempt to mislead the unwary reader into thinking the total ethanol energy output is 35% of the fossil energy input – though he is careful not to actually state that.

 

Pimentel’s support of solar and wind is commendable, but that is no excuse to distort the case for biofuels. It is certainly quite possible that analyses by biofuel supporters are rather optimistic for current standard practice; but this is excusable, as there has been a significant trend toward improving efficiencies over the past 15 years, even though fossil energy costs have been very low during most of that period. With fossil energy costs now rising rapidly, we can expect rapid strides in all efficiencies involved in biofuel production over the next five years.

 

See Shapouri, http://www.ethanolrfa.org/net_energy_balance_2004.pdf , for a balanced analysis of corn-ethanol.

See U.N. report #26, http://www.fertilizer.org/ifa/publicat/pdf/part1.pdf , for all you ever wanted to know about the fertilizer industry.

See Greene, “Growing Energy”, NRDC, http://www.bio.org/ind/GrowingEnergy.pdf for serious analysis on cellulosic ethanol.

See Doty, http://www.dotynmr.com/PDF/Doty_FutureFuels.pdf , for a sound look at Future Fuels.

See Patzek, http://petroleum.berkeley.edu/papers/patzek/CRPS416-Patzek-Web.pdf , for some extremely biased analysis based on obsolete data.

 

F. David Doty, PhD, physics

[cwes99_03]

Wow Doty, you took more than the words out of my mouth, you added a ton of your own. Good work.

 

I don't know much about the actual paper itself, but it seems this is a person or group of people who have dedicated their lives to putting down renewable agrifuels, which may come with a lot of bias.

 

What I find interesting is that I've never read a report that mentions that energy cost of producing a gallon of gasoline. I want to see a side by side comparison of this to the amount of energy cost for producing a gallon of ethanol. Oh yah, and then cut out the cost of actually growing the corn, because the corn is going to be grown regardless. This is just a matter of whether we are going to let as much of it spoil on the ground every year.

 

Truth be told if this report/paper were telling the truth, then Brazil would not be able to sell ethanol at the rate it does to it's own consumers. More than 50% of all new cars being sold down there are flex fuel cars. And ethanol costs less than gasoline does down there (most of the time) and when it doesn't people buy gasoline.

 

On top of all that, to produce ethanol, one does not use the most expensive distillate of oil production, they use coal and other energy sources. Coal is not in short supply from the studies I've read, however oil is.

 

The idea on each farmer having his own still is ludicrous. However, having hundreds of medium sized facilities spread out across the US is already becoming a realized dream. This will greatly cut out the transportation cost.

[Michaelangelica]

Maybe not economic from subsidised US corn;

but what about un-subsidised Australian sugar cane?

 

Germany seems to be going the bio-fuel rd. anyway by the look of this article

Growing Crops for Fuel: Thanksgiving in the Gas Tank - International - SPIEGEL ONLINE - News

Its remote location-and its modesty make Penkun the ideal place for one of the most impressive sets of structures of the coming post-industrial age. Some 40 concrete vats, each 28 meters (92 feet) in diameter, will take up most of the available space in the local industrial zone, launching the biggest organized digestive process in history. Corn produced on 6,000 hectares (14,826 acres) of farmland, totaling more than 200,000 tons a year, will decompose in the containers the way it would in cows' intestines, emitting methane-containing biogas in the process.

 

The artificially produced intestinal gas is a high-quality fuel and will drive an array of 40 six-foot-tall, 12-cylinder motors, which in turn will produce electricity through generators. Nawaro AG, the operator of what will be the world's most productive biogas power plant, plans to have all the cylinders up and running at the first facility by late summer of this year. From then on, they will supply the German power grid with a constant stream of 20 megawatts of electricity.

 

The biogas power plant at Penkun, Germany

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Norbert Michalke

 

The biogas power plant at Penkun, Germany

Although the corn plant in the eastern German state won't exactly be replacing any nuclear power plants at this level, it does mark the first step in an extensive corporate strategy that is expected to transform much of the vegetation in Germany's east into the world's leading source of renewable methane gas. Nawaro AG plans to bring one new electricity factory of the same size on line each year from now on. "But we don't expect to make any money with the first one," explains CEO Balthasar Schramm.