Fresh Corpses, or Why Cellulosic Ethanol Will Not Save Us

November 9, 2006 at 11:49 am
Contributed by: Chris


Today, like many of you no doubt, I am breathing a sigh of relief, rubbing my eyes and feeling like I’m waking up from a long national nightmare. Just as I was about to lose faith entirely in the American people, they went to the polls and threw the bums out. The hatemongers like Santorum, the corrupt friends of Jack Abramoff, the unscrupulous figures who would sooner protect a fellow Congressman than an underage teen…all got their comeuppance. And we even got the resignation of Rummy to boot. The do-nothing 109th Congress has been roundly chastised, and maybe now we can get back to the serious business at hand…like obsessing over the divorce of Brit and K-Fed.

Although there was much about the midterm election to be happy about, California’s Prop 87 was defeated. So we now must begin again to try to shape public policy to develop alternative liquid fuels and reduce our consumption of petroleum.

Or should we? Dr. Tadeusz “Tad” Patzek, Professor of Civil & Environmental Engineering at UC Berkeley, says the expectations around cellulosic ethanol are greatly overblown and, indeed, influenced by politics. At the invitation of Venture Beat, an online blog/journal of Silicon Valley venture capitalists, Dr. Patzek responded to some of the claims about ethanol made by Vinod Khosla in arguing for Prop 87. His response is worth studying, and his questions at the end deserve to be asked and considered. Clearly, he does not believe there is any sort of techno-fix in the offing, and instead asks us to reconsider how and why we use energy, and how we can reduce our consumption. Check it out.


Why Cellulosic Ethanol Will Not Save Us

By Tad Patzek 11.5.06

Source: Venture Beat

Tad Patzek

[Editor’s note: This is the next-to-last piece in our series on the Prop. 87 “oil tax.” Tad Patzek discusses the problems with biomass, which is one of the alternative energy sources the oil tax would fund with research.]

Today it is commonly believed that burning freshly cut plants is morally superior to burning old fossil plants. Even more curiously, some are convinced that stripping ecosystems of gigantic quantities of biomass can go on year-after-year, forever, and with no consequences.

This attitude is best exemplified by the DOE/USDA 2005 report by Perlack et al.: “An annual biomass supply of more than 1.3 billion dry tons can be accomplished with relatively modest changes in land use and agricultural and forestry practices.”

Much of Proposition 87 is built around this delusionary DOE/USDA vision. In his April 2006 presentation, Mr. Khosla proclaimed that US would produce 130 billion gallons of ethanol per year from the imaginary 1.3 billion tons of biomass. Unfortunately, this is impossible regardless of technology.

To arrive at its conclusions, the DOE/USDA report made the following assumptions:

1. Yields of corn, wheat, and other small grains were increased by 50 percent;
2. The residue-to-grain ratio for soybeans was increased to 2:1;
3. The harvest technology was capable of recovering 75 percent of annual crop residues;
4. All cropland was managed with no-till methods;
5. 55 million acres of cropland, idle cropland and cropland pasture were dedicated to the production of perennial bioenergy crops;
6. All manure in excess of that which can applied on-farm for soil improvement under anticipated EPA restrictions was used for biofuel; and
7. All other available residues were utilized.

If these assumptions were not so frightening, they would be laughable:

1. The permanent 50 pecent increase of all crop yields is impossible. The all-time record yield of corn in 2004, 160.1 bushels/acre, was followed by 147.9 bu/acre in 2005, and an estimated 153 bu/acre in 2006. The real yields have been decreasing instead of jumping up by 50 percent.
2. The 2:1 residue-to-grain ratio for soybeans would require a 45 percent increase of the current average harvest index of 0.42, and is not quite achievable.
3. Taking most residues from the fields would leave little or no plant matter to protect the soil from excessive wind and water erosion. The rate of erosion in US agriculture generally exceeds the rate of soil mineral deposition and humus generation.
4. Total no till agriculture would require astronomical quantities of herbicides and pesticides to kill off the “spurious” life competing with the resource-greedy, but otherwise delicate hybrid crop monocultures. Because of the comprehensive loss and poisoning of the natural environment and imported parasites, the honeybee population declined by 60% between 1947 and 2005. Honeybees had to be imported from outside North America last year for the first time since 1922. Bees pollinate an estimated 10-20 billion dollars worth of crops every year.
5. US corn grows on 70 million acres. Dedicating 55 million acres to switchgrass would eliminate plenty of other crops. The total area of the soil Conservation Reserve Program (CRP) in the US is a modest 34 million acres.
6. The EPA requirements are perceived as restrictions. In other words, a modicum of conservation is viewed as an obstacle to feeding our thirsty cars and all remaining land (see Item 5) must go.
7. To utilize all residues, I suggest to also process fresh corpses into biofuels.

One simply cannot remove biomass and nutrients from an ecosystem without putting these nutrients back, protecting the soil structure, and suffering from lower yields in later crop rotations in industrial plantations. The high heating value (HHV) of 1.3 billion tons of biomass is roughly 22 EJ; and the HHV of 130 billion gallons of ethanol is 11.4 EJ. The fictitious DOE energy efficiency of converting biomass to ethanol, 11.4/22 = 0.52, corresponds to Fischer-Tropsch synthesis and is two times higher than efficiency of the current corn-ethanol process. If one were to produce cellulosic ethanol with a 26% efficiency, one would have to use all above-ground biomass of all US crops, pastureland and rangeland, and annual biomass growth over 2/3 of all US forestland and timber plantations.

In summary, the DOE-USDA-Proposition 87 vision is to capture in real time most of net growth of all biomass in the US, while at the same time mining soil, water, and air over 72 percent of our land area, including Alaska, Hawaii, and Puerto Rico. This biomass would then be devoured to feed our inefficient cars. We would have little food production, as well as little wood for paper and construction. In effect, the new brave US economy would be dedicated to feeding cars, not people. This vision has been enthusiastically embraced by some in the US science and industrial establishment.

If one does not buy such obvious delusions and one wants to live better while not destroying the Earth, what is one to do? Instead of stumbling into Proposition 87, it might be better to ask the following questions:

1. What changes of our social and urban infrastructure will be necessary to decrease energy use in the US by a factor of 4-6?

2. How can the public be educated about the inevitable changes of our lifestyles?

3. How can one talk in a sensible way about the complex issues of environment/human interactions? In particular:
(a) How can one formulate the thermodynamics of living ecosystems and bring their descriptions into economic accounting?
(b) How can one consistently compare most energy resources and energy extraction schemes?
(c) How can one quantify the impact of energy supply schemes and life choices on the ecosystems in which we are embedded?
(d) Will there be enough clean air, water, and soil to sustain our society?
(e) How will the progressing global climate change impact energy consumption and production?

The formulation of answers to these questions might start another proposition. That future proposition would be for the people, not their cars.

Tad Patzek is a professor of Civil and Environmental Engineering at UC Berkeley.

No Comments

No comments yet.

RSS feed for comments on this post.

Sorry, the comment form is closed at this time.

Copyright © 2008 GetRealList
All trademarks and copyrights on this page are owned by their respective owners.