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Pioneer cellulosic biorefineries across the United States rely on a conventional feedstock supply system based on one-year contracts with local growers, who harvest, locally store, and deliver feedstock in low-density format to the conversion facility. While the conventional system is designed for high biomass yield areas, pilot scale operations have experienced feedstock supply shortages and price volatilities due to reduced harvests and competition from other industries. Regional supply dependency and the inability to actively manage feedstock stability and quality, provide operational risks to the biorefinery, which translate into higher investment risk. The advanced feedstock supply system based on a network of depots can mitigate many of these risks and enable wider supply system benefits. This paper compares the two concepts from a system-level perspective beyond mere logistic costs. It shows that while processing operations at the depot increase feedstock supply costs initially, they enable wider system benefits including supply risk reduction (leading to lower interest rates on loans), industry scale-up, conversion yield improvements, and reduced handling equipment and storage costs at the biorefinery. When translating these benefits into cost reductions per liter of gasoline equivalent (LGE), we find that total cost reductions between –$0.46 to –$0.21 per LGE for biochemical and –$0.32 to –$0.12 per LGE for thermochemical conversion pathways are possible. Naturally, these system level benefits will differ between individual actors along the feedstock supply chain. Further research is required with respect to depot sizing, location, and ownership structures. Published 2015. This article is a U.S. Government work and is in the public domain in the USA. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.

The 2011 US Billion-Ton Update estimates that by 2030 there will be enough agricultural and forest resources to sustainably provide at least one billion dry tons of biomass annually, enough to displace approximately 30% of the country's current petroleum consumption. A portion of these resources are inaccessible at current cost targets with conventional feedstock supply systems because of their remoteness or low yields. Reliable analyses and projections of US biofuels production depend on assumptions about the supply system and biorefinery capacity, which, in turn, depend upon economic value, feedstock logistics, and sustainability. A cross-functional team has examined combinations of advances in feedstock supply systems and biorefinery capacities with rigorous design information, improved crop yield and agronomic practices, and improved estimates of sustainable biomass availability. A previous report on biochemical refinery capacity noted that under advanced feedstock logistic supply systems that include depots and pre-processing operations there are cost advantages that support larger biorefineries up to 10 000 DMT/day facilities compared to the smaller 2000 DMT/day facilities. This report focuses on analyzing conventional versus advanced depot biomass supply systems for a thermochemical conversion and refinery sizing based on woody biomass. The results of this analysis demonstrate that the economies of scalemore » enabled by advanced logistics offsets much of the added logistics costs from additional depot processing and transportation, resulting in a small overall increase to the minimum ethanol selling price compared to the conventional logistic supply system. While the overall costs do increase slightly for the advanced logistic supply systems, the ability to mitigate moisture and ash in the system will improve the storage and conversion processes. In addition, being able to draw on feedstocks from further distances will decrease the risk of biomass supply to the conversion facility.« less

Over 9 million dairy cows generate an estimated 226 billion kg of wet manure annually in the USA. To help mitigate dairy greenhouse gas (GHG) emissions associated with the degradation of this organic-rich waste, manure can be processed via anaerobic digestion (AD) to methane and ultimately electricity. This potential value of AD has generated high-level dairy-industry support for broad-scale technology deployment; however, on-the-ground AD realization has been impeded by process stability/reliability concerns and poor economics. Considering these challenges but recognizing that AD represents a fundamentally sound manure-management approach, an interdisciplinary research team has completed proof-of-concept investigations on an integrated process that will concurrently improve manure management economics and reduce dairy GHG emissions. The integrated processes center on a two-stage fermentation/AD system that can generate methane quantity/quality comparable to conventional single-stage AD. Molecular level investigations confirm that the AD is highly enriched with a unique and synergistic microbial population which yielded a more resilient and stable process. Beyond AD, algae grown on nitrogen/phosphorus-rich AD supernatant in a photobioreactor yielded biomass concentrations approaching 1.0 g L–1; despite an apparent growth lag/inhibition associated with excess organic acids and ammonia, algae growth was significant. Environmental life cycle assessment (LCA) demonstrated that the two-stage AD configuration coupled with algae production can reduce GHG emissions by approximately 60% as compared with a traditional anaerobic lagoon. The end result is a manure-management platform that can increase US dairy viability and sustainability. Ongoing investigations are aimed at process refinement with an ultimate commercialization goal. © 2013 Society of Chemical Industry and John Wiley & Sons, Ltd

This techno-economic study investigates the production of ethanol and a higher alcohols coproduct by conversion of lignocelluosic biomass to syngas via indirect gasification followed by gas-to-liquids synthesis over a precommercial heterogeneous catalyst. The design specifies a processing capacity of 2,205 dry U.S. tons (2,000 dry metric tonnes) of woody biomass per day and incorporates 2012 research targets from NREL and other sources for technologies that will facilitate the future commercial production of cost-competitive ethanol. Major processes include indirect steam gasification, syngas cleanup, and catalytic synthesis of mixed alcohols, and ancillary processes include feed handling and drying, alcohol separation, steam and power generation, cooling water, and other operations support utilities. The design and analysis is based on research at NREL, other national laboratories, and The Dow Chemical Company, and it incorporates commercial technologies, process modeling using Aspen Plus software, equipment cost estimation, and discounted cash flow analysis. The design considers the economics of ethanol production assuming successful achievement of internal research targets and nth-plant costs and financing. The design yields 83.8 gallons of ethanol and 10.1 gallons of higher-molecular-weight alcohols per U.S. ton of biomass feedstock. A rigorous sensitivity analysis captures uncertainties in costs and plant performance. © 2012 American Institute of Chemical Engineers Environ Prog, 2012

Abating the dependence of the United States on foreign oil by reducing oil consumption and increasing biofuels usage will have far-reaching global effects. These include reduced greenhouse gas emissions and an increased demand for biofuel feedstocks. To support this increased demand, cellulosic feedstock production and conversion to biofuels (e.g. ethanol, butanol) is being aggressively researched. Thus far, research has primarily focused on optimizing feedstock production and ethanol conversion, with less attention given to the feedstock supply chain required to meet cost, quality, and quantity goals. This supply chain comprises a series of unit operations from feedstock harvest to feeding the conversion process. Our objectives in this review are (i) to summarize the peer-reviewed literature on harvest-to-reactor throat variables affecting feedstock composition and conversion to ethanol; (ii) to identify knowledge gaps; and (iii) to recommend future steps.