First Name: | Stephen |
---|---|
Last Name: | Kaffka |
Email Address: | srkaffka@ucdavis.edu |
Affiliation | Department of Plant Sciences, UC Davis |
Subject | Proposed Corn Oil Biodiesel Ppathway |
Comment |
23 February 2011 Mr. John Courtis Manager, Alternative Fuels Section California Air Resources Board P.O. Box 2815 Sacramento, CA 95812 Re: “Detailed California-Modified GREET pathway for Corn Oil Biodiesel (COB)”_December 14, 2010. Dear John, In the proposed Low Carbon Fuel Standard (LCFS) pathway)for Corn Oil Biodiesel (COB), CARB treats COB as a residue of the starch ethanol process. No green house gas costs are attributed to production of the oil fraction of the corn grain extracted after starch conversion to ethanol. Secondly, there does not appear to be any adjustment of the altered DDGS meal. DDGS is an important livestock feed for cattle, hogs and poultry, and an internationally traded commodity. I have two concerns about this approach: 1. Feeds are used based primarily on their energy, protein, fiber and some secondary properties. They are combined with other feeds using these qualities to calculate a total mixed diet or ration. These rations are dynamic, sensitive to price, livestock species, stage of growth and many other considerations. When corn oil is removed from DDGS, its energy value will be affected and perhaps other quality characteristics that could affect livestock performance like palatability or intake. At a minimum, a livestock feeder will have to find some other source of plant oil or energy to compensate. Currently, CARB provides a by-product feeding credit to adjust for the use of DDGS in livestock feeds and its displacement of crops for which it compensates. This comes from GREET. While the GREET values are just approximations for a far more complicated pattern of use in livestock feeding, they recognize of that use and estimate associated crop displacement. It is not clear to me if livestock performance trials with modified DDGS have been carried out or even if calculations based on existing nutritional formulations have been made. Perhaps they have and I missed that explanation. But if not, some accounting for altered nutritional value must be included. It is not clear if de-oiled DDGS will be significantly different from standard DDGS or if it will effect use by all livestock species equally. If differences are significant and result in reduced use of DDGS or other feed substitutions, then the GHG benefits of using corn oil may not be real, or as large as estimated by CARB. In any case, consistency in methods as far as possible seems to me be an essential characteristic for the success of the LCFS. 2. Land Use Change is a result of decisions about which crop to grow. COB production likely will increase the value of corn to ethanol refiners, and it may also influence the price of corn relative to other crop alternatives as well. While there are different ways to proportion production costs to various products, it seems that all products have such costs, especially in so far as they influence land use decisions including acres, inputs, and cultivars, through modifying demand for the feedstock. Many ethanol businesses are coops, and the owners include farmers who produce the grain feedstocks. But even for growers who are not coop owners, but sell into the corn grain market, the acreage decision is affected by price considerations. This suggests to me that corn oil should also have a portion of the grain production costs associated with it. This is not done in the proposed COB pathway. If I understand correctly, the oil simply appears at some point in the production process, is considered a waste without alternative uses, and then a Carbon Intensity is calculated based only on manufacturing costs. This seems inconsistent to me with other pathways estiamted by CARB, risks over- or undervaluing COB, and compromises the ethanol calculations used in the LCFS. Critical to this entire consideration is the magnitude in the changes to DDGS and the effect on demand for corn grain that COB might induce. If they are small, then, these are not important concerns. But the issue of consistency remains. Thank you for considering these comments. Best wishes, Steve Kaffka Department of Plant Sciences University of California Davis, CA 95616 srkaffka@ucdavis.edu |
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Original File Name:
Date and Time Comment Was Submitted: 2011-02-23 14:45:07 |
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