Feedstock based challenges

Resource Availability and Cost
Sustainable Production
Crop Genetics

Resource Availability and Cost: Feedstock supply is a significant cost component of bio-based fuels, products, and power. The lack of credible data on price, location, quality and quantity of biomass creates uncertainty for investors and developers of emerging biorefinery technologies. Current estimates of feedstock resources are limited in scope, and do not consider how major technological advantages in production technologies will impact biomass availability.

Sustainable Production: Existing data on the environmental effects of feedstock production and residue collection are not adequate to support lifecycle analysis of biorefinery systems. The lack of information and decision support tools to predict effects of residue removal as a function of soil type, and the lack of a selective harvest technology that can evenly remove only desired portions of the residue make it difficult to assure that residue biomass will be collected in a sustainable manner. The production and use of energy crops also raise a number of sustainability questions (such as water and fertilizer inputs, establishment and harvesting impacts on soil, etc.) that have not been comprehensively addressed.

Crop Genetics: There is inadequate information on plant biochemistry, as well as insufficient genomic and metabolic data on many potential biomass crops. Genetic modification of energy crops for improved characteristics may create risks to native populations of related species, and any modification of commodity crops to improve residue characteristics may affect grain values.

Feedstock Logistics Technical Challenges

Sustainable Harvest
Feedstock Quality and Monitoring
Storage Systems
Biomass Material Properties
Biomass Physical State Alteration (i.e., grinding, densification, and blending)
Biomass Material Handling and Transportation

Sustainable Harvest: Cellulosic biomass variability places high demand and functional requirements on biomass harvesting equipment. Current systems can neither meet the capacity, efficiency, or delivered price requirements of large cellulosic biorefineries, nor can they effectively deal with the large biomass yields per acre of potential new biomass feedstock crops. In addition, feedstock specifications and standards to engineer harvest equipment, technologies, and methods, do not currently exist.

Feedstock Quality and Monitoring: Physical, chemical, microbiological, and postharvest physiological variations in feedstocks arising from differences in variety, geographical location, and harvest methods are not well understood. Passive, noninvasive analytical tools and sensors for rapid and/or real-time compositional and conversion efficiency measurements for cellulosic feedstocks are needed.

Storage Systems: Stored biomass that becomes wet is susceptible to spoilage, rotting, spontaneous combustion, and odour problems; therefore, the impact of these post-harvest physiological processes must be controlled to the benefit of biorefining processes. Engineering analysis of unconventional storage methods, including centralized versus distributed systems, is needed to define storage requirements. Key elements requiring better understanding include storage biomass losses, infrastructure for package (i.e., bale, silage wrap, etc.), bulk stored biomass, storage bulk density, and post-harvest physiology of storage systems.

Biomass Material Properties: Data on biomass quality and physical property characteristics for optimum conversion are limited. Information on functional moisture relations on quality and physical properties of biomass as affected by crop variability and climatic conditions during harvest and post-harvest operations is incomplete. Methods and instruments for measuring physical and biomechanical properties of biomass are lacking.

Biomass Physical State Alteration (i.e., grinding, densification, and blending): The harvest season for most crop-based cellulosic biomass is short, especially in northern climates, thus requiring preprocessing systems that facilitate stable biomass storage, densification, and blending for year-round feedstock delivery to biorefineries. The initial sizing and grinding of biomass affect efficiencies and quality of all the downstream operations; yet, little information exists on these operations with respect to the multiplicity of cellulosic biomass resources and biomass format requirements for biorefining.

Biomass Material Handling and Transportation: The low density and fibrous nature of cellulosic biomass make it difficult and costly to collect, handle and transport. Present methodologies for collecting, storage handling, transport, and in-biorefinery handling of the biomass are too costly and inefficient for handling million ton quantities of biomass.

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