The challenge of biofuel crops

A variety of plant materials, technically called ‘biomassDescription Mass of organic matter of non-fossil biological origin which can be exploited for energy purposes. Authoritative On-line References and Resources http://www1.eere.energy.gov/biomass The US Department of Energy's Office of Energy Efficiency and Renewable Energy has a Biomass Program working with industry, academia and US National Laboratories on research into biomass feedstocks and conversion technologies. The goal is cost competitive, high performance biofuels, bioproducts, and biopower.’, can be processed into biofuelsDescription Fuel derived from biomass. Authoritative On-line References and Resources http://www.biofuelstp.eu/ The European Biofuels Technology Platform is upportd by the European Commission and aims to help develop cost-competitive, world class biofuel technology, contribute to the creation of a European biofuels industry and to identify the research needed to achieve this.. BiodieselDefinition Mono-alkyl esters of long chain fatty acids derived from vegetable oils or animal fats for use in diesel engines. It refers to pure fuel before blending with conventional diesel fuel. Blends are denoted as, "BXX" with "XX" representing the percentage of biodiesel contained in the blend (ie: B20 is 20% biodiesel, 80% petroleum diesel). Authoritative On-line References and Resources http://www.eere.energy.gov/afdc/fuels/biodiesel.html The US Department of Energy's Office of Energy Efficiency and Renewable Energy has an Alternative Fuels and Advanced Vehicles Data Center containing key information on all biofuels. is the product of vegetable oils derived from soybeans, sunflowers, rapeseed, palm, coconuts, and other more exotic sources such as jatropha seeds. BioethanolDescription Bioethanol is ethanol of biological origin. Crops containing sugar or starch grown for energy use include sugar beet, sugar cane, maize and wheat. "2nd generation" bioethanol will be made from cellulose from, e.g. waste straw and stover, willow and popular trees, sawdust, reed canary grass, switchgrass, Miscanthus. Authoritative On-line References and Resources http://www.eere.energy.gov/afdc/fuels/ethanol.html The US Department of Energy's Office of Energy Efficiency and Renewable Energy has am Alternative Fuels and Advanced Vehicles Data Center containing key information on all biofuels. comes from the fermentation of corn, sugar beet and sugar cane, switchgrass, and wheat, as well as other starchy or cellulosic plant material.

Ethanol use far outstrips biodiesel globally, as ethanol has more mature markets and infrastructure. In the U.S., where it is mostly produced from corn, ethanol has been blended with gasoline for many years.

The high fossil fuel energy input to manufacturing and for transport to market currently undermines the promise of U.S. corn-based ethanol as a solution to global warming and energy security. Some schemes to set-up ethanol production in fact depend on coal and diesel energy to run ethanol plants. Ethanol made in Brazil from sugar cane, on the other hand, stands on an efficient process honed since the 1970’s oil crises, and reduces greenhouse gas emissions by 80%.  Biodiesel on the whole remains more fuel-efficient and less emissions-intensive than ethanol. Studies show that biodiesel on average is about four times as efficient as petroleum diesel when considering all energy inputs and fuel mileage and carbon uptake of plants. Ethanol is about twice as efficient.

Production and use of biodiesel not only results in a reduction in carbon dioxide emissions, but, unlike petroleum diesel, also avoids emission of lead, sulfur or toxic aromatics such as benzene, toluene, and xylene. In Europe, where diesel technology is more advanced and widespread, biodiesel currently has more potential for commercial and civilian transport than it does in the U.S. Biodiesel production in Europe far outstrips production in the U.S. The ease with which biodiesel can be blended with conventional petrodiesel is perhaps its best selling point. Vehicles with conventional diesel engines can run on 20% blends without need for modifications.

Within the next decade or so, cereal straw and corn stover are expected to make a major contribution to the production of biofuels. At present, grain and other sources of starch and sugars are used to make ‘first generation’ bioethanol. Soon, the process technology to make ‘second generation’ biofuels, from cellulose in stover and straw will be implemented in ‘biorefineries’.

Biofuels need no-till and paraquat

Straw and stover are not waste products and already play an important role in cropping systems. Crop material left in fields after harvest, helps to prevent erosion, provides habitats for wildlife, and increases the level of soil organic matter. It ultimately adds to the organic matter which is important for the structure, stability, and productivity of soil. In the near future, therefore, there will be a conflict between using crop remains for soil management and collecting it as biomass to produce biofuels.

The solution to this dilemma is to increase the amount of cropland under no-till cultivation. Large increases in the area of no-till in the US have been recommended in order to meet the country’s future annual requirements estimated at over one billion tonnes of biomass. No-till has three key benefits in biofuels production:

1. No-tilled soils are more stable and less susceptible to erosion allowing more straw to be removed,
2. No-till means substantially less fuel is consumed in crop production, increasing the net energy contribution of biofuels,
3. Partly because less fuel is used, but much more significantly because soil organic matter levels increase, no-till soils sequester large amounts of carbon dioxide – with important implications for its role as a greenhouse gas in global warming.

As weeds are not controlled by plowing in no-till, its success relies on the use of non-selectiveDescription A chemical product used for eliminating all types of weeds (annual and perennial grasses and broadleaved weeds). Authoritative On-line References and Resources http://www.weeds.iastate.edu/ An invaluable source of contemporary information about herbicides and weeds from Iowa State University. herbicides like paraquat. Paraquat has many benefits and is the best choice when fast action and rainfastness are needed. Paraquat has no soil residual activity and contributes to minimizing soil erosionDescription Displacement of solids (soil, mud, rock and other particles) usually by the agents of currents such as, wind, water, or ice by downward or down-slope movement. Authoritative On-line References and Resources http://soilerosion.net/ This site brings together reliable information on soil erosion from a wide range of disciplines and sources. It aims to be the definitive internet source for those wishing to find out more about soil loss and soil conservation. by only destroying shoot growth. Roots are left intact and provide an anchoring effect. In addition, paraquat is an essential component in rotating herbicides to avoid weed resistanceDescription The inherited ability of a plant/weed to survive a dose of a herbicide normally lethal to that species. Authoritative On-line References and Resources http://www.weedscience.org/in.asp The International Survey of Herbicide Resistant Weeds monitors the evolution of resistant species and assesses their impact. All confirmed instances of new cases are listed..

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