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News and Trends
http://pubs.acs.org/doi/full/10.1021/es800367m (full text html version) Researchers from the University of Texas at Austin (United States) recently reported the use of a “Water Intensity” index, to compare/assess water consumption and withdrawal during the production and use of conventional and alternative fuels. They defined the water intensity index as “water usage per mile driven” (in the units, gallons water/mile). Their results showed that the lowest levels of water intensity (less than 0.15 gal/mile for water consumption and 1 gal/mile water withdrawal) were for light duty vehicles (LDV’s) using: (1) conventional petroleum-based gasoline/diesel, (2) non-irrigated biofuels, (3) hydrogen derived from methane or electrolysis via non-thermal renewable electricity, (4) electricity from non-thermal renewable energy resources. Biofuels from irrigated feedstocks in the United States were found to have relatively high values for LDV water intensities. For corn ethanol, water consumption and water withdrawal intensities were 28 gal/mile and 36 gal/mile, respectively. For soybean biodiesel, the water consumption and withdrawal intensities were 8 gal/mile and 10 gal/mile, respectively. Countries with limited water resources may need to carefully map out their own national biofuel policies considering the potential impacts of alternative fuels on water use. The full results are published in the September 2008 issue of the Environmental Science and Technology journal (URL above).. http://www.jgpress.com/archives/_free/001796.html The Biocycle website reports some updates on nine cellulose ethanol projects under the United States Department of Energy (US-DOE)-Grants to accelerate the development of the cellulose ethanol industry. The grant funds ranged from US$ 25 million to US$ 30 million in funds (per grantee), covering 50 percent of design/construction of “one-tenth commercial scale biorefineries that serve as prototypes for full-scale commercial opportunities.” The projects have diverse lignocellulosic feedstocks (sugarcane bagasse, wood chips, wheat straw, etc) and pretreatment processes (mild acid treatment, steam explosion, wet oxidation, etc), all leading to ethanol as the final product. While some are in the construction phase of demonstration scale facilities, some have been affected by the recent economic downturn and had to be scaled-back or renegotiated. The report gives specific updates on the companies which were granted funds by the US-DOE: Verenium Corporation, Lignol Energy Corporation, Pacific Energy Inc., ICM Inc., Alltech, Mascoma Corporation, Flambeau River Biofuels Inc., Newpage and RSE..
http://www.biofuelsdigest.com/blog2/2009/01/30/japan-airlines-biofuels-flight-test-a-success-camelina-algae-jatropha-used-in-b50-biofuel-mix-fuel-economy-higher-than-jet-a/ Japan Airlines is reported to be the first Asian airline to have conducted a successful demonstration flight on an aircraft (Boeing 747-300) with one engine run by a “cocktail blend” of the following second generation biofuels: camelina (84%), jatropha (less than 16%) and algae (less than 1%). The one-and-a half hour test flight conducted in January this year had no modifications on the biofuel-powered jet engine, and the biofuel blend was used as a “drop-in replacement” for the conventional petroleum-based fuel. Camelina (also known as “false flax”), is considered a good biofuel feedstock because of its high oil content and its ability to grow in rotation with wheat and other cereal crops. These are in addition to camelina being non-food-based bioenergy crop. According to Boeing Japan President, Nicole Piasecki, the airline industry is “already working to secure its fuel future supply by establishing firm sustainable criteria to ensure that environmental impacts and carbon dioxide emissions from biofuels are significantly lower than fossil-fuel-based kerosene fuels”. Related information on camelina: http://www.biotechnologyforbiofuels.com/content/1/1/5 Scientists from the University of Copenhagen (Denmark) and the Southern Research Station of the United States Department of Agriculture (USDA) have reported the effect of hydrothermal pretreatment of wheat straw on the straw’s cell-wall matrix and its composition, using atomic force microscopy and scanning electron microscopy. Pretreatment is usually the first step in the production of cellulose-ethanol from lignocellulosic biomass, such as wheat straw. The purpose is usually to delignify (remove lignin) and to render the cellulose fibers in the plant biomass more susceptible to enzymatic conversion into sugars for ethanol production. Hydrothermal treatment is one pretreatment option. Under this method, the chopped and preheated (80 oC) wheat straw is placed inside an airtight reactor and injected with stream at 195 oC for an average reaction time of 6 minutes. In contrast to steam explosion treatment (heating the biomass with steam under pressure, then rapidly releasing the pressure, causing the fibers to explode), hydrothermal treatment is reportedly a milder pretreatment method. According to the report, “recent results indicate that only a mild pretreatment is necessary in an industrial, economically feasible system”. The scientists found that hydrothermal treatment “does not degrade the fibrillar structure of cellulose but causes profound lignin re-localisation”. Partial removal of wax and hemicellulose was also observed. The changes in hydrothermally-treated wheat straw was similar to those in (the more intensive) steam-exploded wheat straw. Details of the report can be found in the online access, peer-reviewed journal, Biotechnology for Biofuels (URL above).. Energy Crops and Feedstocks for Biofuels Production
http://news.rutgers.edu/medrel/research/sequencing-of-sorghu-20090127 A team of Rutgers University (United States) scientists and international collaborators recently described the sorghum genome, in a paper published in the January 29, 2009 issue of the journal, Nature. Joachim Messing, director of the Waksman Institute at Rutgers University, and co-author of the paper, developed the “shotgun approach” that was used in the sorghum sequencing. According to the Rutgers University website article, “this approach takes into account the highly repetitive nature of large genomes including many plant species and the human genome. By using paired sequence reads instead of single sequence reads, the scientists can jump over repeat sequences, constituting about 62 percent in sorghum, and produce an accurate and contiguous picture of the entire sorghum genome”. This development paves the way for the production of better sorghum crops that can be tailored for food or biofuel applications.. Biofuels Processing
http://pubs.acs.org/doi/abs/10.1021/ja808537j?prevSearch=%28Raines%2C+R%29+AND+%5Bauthor%3A+Raines%2C+Ronald+T.%5D&searchHistoryKey= Researchers from the Department of Chemistry and Biochemistry at the University of Wisconsin Madison (United States) have recently reported the use of a “simple chemical transformation” process to convert lignocellulosic biomass into biofuels. Their study is recently published in the Journal of the American Society (URL above). Presently, the biochemical route is the more common method for the conversion of lignocellulosic biomass into biofuel, ethanol (often named “cellulosic ethanol”). This involves multi-step processes from pretreatment (lignin removal), to saccharification (cellulose conversion to simple sugars), and then fermentation (microbial conversion of simple sugars to ethanol). The reported chemical process utilizes a patent-pending solvent system which dissolves cellulose in the plant biomass and converts them into the chemical, 5-hydroxymethylfurfural (HMF) (first step). HMF is said to be a “chemical platform” from which other useful biofuels can be made. According to doctoral student and co-author, Ronald Raines, the solvent system is “not corrosive, dangerous, expensive or stinky”. The cellulose-to-HMF conversion process is also unaffected by the presence of lignin, protein, and other components in the plant biomass. In the second step, the converted HMF is transformed to 2,5-dimethylfuran (DMF), a promising biofuel. The process has been tested on corn stover, and pine sawdust. The current yield of the process estimated at 30 gallons of the biofuel product per ton of biomass processed. Optimization of the second step is ongoing.. Biofuels Policy and Economicshttp://www.pnas.org/content/early/2009/02/02/0812835106.full.pdf+html (may require paid subscription for complete access) A recent article from the Proceedings of the National Academy of Sciences (PNAS) (February 10, 2009 issue) attempts to “quantify and monetize the life-cycle climate-change and health effects of greenhouse gas (GHG) and fine particulate matter (PM2.5 ) emissions from gasoline, corn ethanol, and cellulosic ethanol. The paper by Jason Hill (University of Minnesota) and colleagues is titled, “Climate change and health costs of air emissions from biofuels and gasoline”. Results estimate that at $120 per Mg Carbon (1 Mg= 1 Mega gram), the cost estimates from increased GHG levels caused by production and combustion of an additional billion gallons of ethanol or an energy-equivalent amount of gasoline using some of the alternative methods are: $246 million for gasoline, $246 million for corn ethanol (natural gas heat), $56 million for switchgrass-based cellulosic ethanol and $21 million for prairie-biomass based cellulosic ethanol. The report mentions that cellulose ethanol fared better compared with corn ethanol because “cellulosic ethanol from corn stover or perennial crops requires lower inputs” (i.e., lower fertilizer and water requirements). Cellulosic ethanol also has “lower emissions at the biorefinery because lignin combustion provides process heat and power, thereby displacing fossil fuel inputs and electricity production”. The complete paper can be accessed at the URL above. On the other hand, the Renewable Fuels Association (URL below) responded to the report, saying that the analysis is based on “based almost entirely upon insufficient and extremely uncertain analysis of potential land use changes” (related information below). Related information on response of the Renewable Association of America to the report http://www.ethanolrfa.org/objects/documents//u_of_m_-_ethanol_worse_than_gas_analysis.pdf
http://pubs.acs.org/doi/abs/10.1021/es802681k A study by scientists from the University of Michigan and Philips Academy Andover (United States) shows that “effective land management practices can reduce the so called carbon debt attributed to biofuels, to near zero.” According to the study, “no-till agriculture” can reduce greenhouse gas emissions (GHG) attributed to biofuels. The complete results are published in a recent issue of the Environmental Science and Technology journal (volume 43 (2009)). The Biotechnology Industry Organization website summarizes the study as follows: (1) important variables that can improve greenhouse emissions from biomass cultivations have not been included in presently published land use studies, (2) “no-till agriculture can reduce the carbon debt associated with converting grassland and temperate zone forests to crop production to 4 and 20 years, respectively”, (3) “no-till with cover crop agriculture can create a carbon sink, resulting in higher soil organic carbon levels than those in unmanaged forests and grasslands”. The concept of “carbon debt for biofuel feedstocks” has been proposed by David Tillman as a “corollary to their carbon capture” (related information below). It is defined as “the amount of carbon dioxide released during the first 50 years of the process of clearing land for production of biofuel feedstocks.” Associated with “carbon debt” is the “carbon payback period” (the period that the “carbon debt” is paid when the cultivated feedstocks uptake carbon dioxide). Related information: http://www.sciencemag.org/cgi/content/abstract/sci;319/5867/1235?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=Land+Clearing+and+Biofuel+Carbon+Debt |
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