Category Archives: Cellulosic Energy Cropping Systems

Use Efficiencies for Radiation, Water and Nitrogen

Potential biomass production depends on the accumulated amount of photosynthetically active radiation (SPAR) intercepted by the crop over the course of its growth and the efficiency with which the crop is able to convert this radiation into carbohydrates, which is known as the radiation use efficiency or RUE [31]. The contribution of each of these processes to biomass production is […]

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Pretreatment

The following step is the pretreatment of the fractionated material. The main goal of pretreatment is to overcome this lignocellulosic recalcitrance, to separate the cellulose from the matrix polymers, and to make it more accessible for enzymatic hydrolysis. Reports have shown that pretreatment can improve sugar yields to greater than 90% theoretical yield for biomass such as wood, grasses, and […]

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Technologies for Production. of Heat and Electricity

Jacob J. Jacobson and Kara G. Cafferty Idaho National Laboratory, U. S.A. 2.2 Introduction In 1978, the United States enacted the Public Utilities Regulatory Policy Act (PURPA) giving small electricity producers (less than 80 MW) a natural monopoly by requiring electric utilities to purchase the small companies’ surplus electricity at a price equal to the cost the utility would have […]

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Cellulosic Biomass Properties and Their Relevance to Downstream Processing

The choice of biomass feedstock is a critical driver in determining key performance metrics of bioenergy — including economic viability, scale of production (both at individual facilities and in aggregate), and environmental impact. For commodities such as fuels or electricity, feedstock cost typically represents two-thirds of the product cost, or more [26]; therefore, selecting a cost-effective feedstock is essential. As […]

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Genetic Diversity for Biomass Production

Only a few Miscanthus species — M. x giganteus, M. sinensis and M. sacchariflorus — have been investigated regarding biomass productivity and composition for breeding potential. Miscanthus x giganteus, in particular, has demonstrated high productivity [39] in low input systems and a higher energy output:input ratio than maize [3]. However, Miscant­hus x giganteus has a narrow genetic diversity [16] and […]

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Hydrolysis

Hydrolysis is the process by which water splits a larger molecule into two smaller molecules. In the case of the hydrolysis of polysaccharides to soluble sugars this is called “saccharifica­tion”. The goal of this process is the de-polymerization of cellulose and hemicelluloses into soluble monomer sugars (hexoses and pentoses). This can be accomplished by two different processes: (1) acid hydrolysis […]

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Moisture Content

Biomass moisture content is defined as the amount of water in the biomass expressed as a percentage of the material’s weight; reporting on a wet basis is most common. Moisture content at harvest for woody feedstocks is usually 40-60% (wet basis); for herbaceous crops, it typically ranges from 10 to 70% (wet basis) depending upon the species, climate, geographic location, […]

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Genetic Diversity for Biomass Composition

To date, Miscanthus biomass has been mainly used to generate renewable heat, electricity and combined heat and power. Its use in biofuel production is under investigation in several countries, as is its potential as a component in bio-based concrete materials and bio-based plastic composites (Section 4.4.1, Past and Current Projects). The composition of Miscanthus biomass must be optimized to suit […]

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Fermentation

The released sugars can now be converted into a broad spectrum of biochemicals and biofu­els through fermentation. An enormous variety of microorganisms, such as yeasts, bacteria, or fungi, exist that can be added to the mixture of free sugars to be fermented into advanced biochemicals, including biofuels. Although organisms exist to break down virtually any organic material, six-carbon sugars, and […]

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