Value chain analysis of bio-coal business in Finland: Perspectives from multiple value chain members

The purpose of this study is to provide a comprehensive outline of the Value Chain (VC)¹ of bio-coal in Finland, define the proper business models of bio-coal business, and investigate the interrelationships between VC activities. The major findings are: 1) the study found significant interrelationships between support and primary activities in the bio-coal VC which suggest that we should not emphasis only the core value/primary activities of the bio-coal business, but pay more attentions to the “side values”/support activities; 2) The study identified political and environmental factors as the effective drivers, while technology and cost-profit uncertainty as major restrictions for the Finnish bio-coal business. The authors would like to suggest that instead of purely “environmental concerns”, the term “sustainability credentials” should be emphasized, which means value creating and adding items should not limit to monetary values, but consider social and environmental value propositions. 3) The study identified “low competition” in the current bio-coal business in Finland, which implies opportunities of market entrance for Finnish and international companies; 4) The study identified that the current Finnish bio-coal model is the decentralized model at the local level. However, the future Finnish bio-coal model will be a large scaled model, with a focus on export sales.     

Biomass yield,nitrogen response,and nutrient uptake of perennial bioenergy grasses in North Carolina

Although perennial grasses show considerable potential as candidates for lignocellulosic bioenergy production, these crops exhibit considerable variation in regional adaptability and yield. Giant miscanthus (Miscanthus × giganteus Greef & Deuter), Miscanthus sinensis Anderss. ‘Gracillimus’ and MH2006, plume grass (Saccharum arundinaceum Retz.), ravenna grass (Saccharum ravennae (L.) L.), switchgrass (Panicum virgatum L. ‘Alamo’), and giant reed (Arundo donax L.) field plots were established in 2008, treated with four nitrogen (N) fertilizer rates (0, 34, 67, 134 kg ha⁻¹ y⁻¹), and harvested annually in winter from 2008 to 2011. Giant reed, ‘Gracillimus’, switchgrass, MH2006, giant miscanthus and ravenna grass at the Mountain site produced mean dry matter yields of 22.8, 21.3, 20.9, 19.3, 18.4, and 10.0 Mg ha⁻¹ y−¹, respectively (averaged over the last two years). Dry matter yields at the Coastal site for giant reed, giant miscanthus, switchgrass, ravenna grass, and ‘Gracillimus’ were 27.4, 20.8, 20.1, 14.3, and 9.4 Mg ha⁻¹ y⁻¹, respectively (averaged over the last two years). Increasing N rates up to 134 kg N ha⁻¹ did not have a consistent significant effect on biomass production. High yields coupled with high mortality for plume grass at both sites indicates its potential as a bioenergy crop and need for continued improvement. Overall, the perennial grasses in this study had low nutrient removal, although giant reed and plume grass often removed significantly more N, P, K and S compared with Miscanthus spp. and switchgrass. Our results indicate that giant reed, giant miscanthus, and switchgrass are productive bioenergy crops across geographic regions of North Carolina.     

The MILESTONES modeling framework: An integrated analysis of national bioenergy strategies and their global environmental impacts

Bioenergy policies affect both the environment and biomass availability for food, feed, and fiber on a national and international scale. To support policy makers, knowledge and methods from different scientific disciplines in the form of integrated assessments is necessary. Therefore we developed the MILESTONES framework which models the links between the national bioenergy system and the global land-use system as an integrated modeling approach. It builds on a set of three well-tested models (MAGNET, LandSHIFT and BENSIM). The prototype's functionality was demonstrated by assessing the environmental impacts of future German bioenergy strategies on a global level and along the entire biomass provision chain. The results from the case study show that, on the one hand, German bioenergy strategies have little effect on international market prices, but on the other hand land-use policies on an international level strongly influence the environmental performance of any German bioenergy strategy.     

Long-term water balance and sustainable production of Miscanthus energy crops in the Loess Plateau of China

Sustainable production of second-generation energy crops on marginal land holds a great potential for renewable energy development. Because a vast area of marginal land is located in the arid and semiarid regions of the world, water shortage is the most serious environmental limitation. In this study, we developed a water balance model to address the question of whether Miscanthus energy crops can be sustainably produced in the Loess Plateau of China, a region of more than 60 million hectares particularly abundant in semiarid marginal land. The simulation of 20-year soil water content in bare soil, the winter wheat field, and the Miscanthus field across the Loess Plateau suggested that the long-term production of Miscanthus would not cause water depletion in deep soil. This finding addressed a serious concern that growing high-biomass plants in the Loess Plateau might lead to deep-soil water depletion, which was suggested to be the cause of previous failure of afforestation. Planting Miscanthus was effective in reducing surface runoff and consequently preventing water and soil loss in this heavily eroded region. The model and analyses illustrated where in the Loess Plateau this perennial energy crop could be produced with stable and sufficient yield.     

An excellent universal catalyst support-mesoporous silica: Preparation,modification and applications in energy-related reactions

As a kind of versatile, excellent catalyst carriers, mesoporous silicas (mSiO₂) have been widely applied for preparing various supported catalysts with ideal catalytic properties due to their uniform and regular channels, adjustable medium pore size, big surface area, controllable wall composition, high hydrothermal stability, easy functional modification and good accessibility of larger reactant molecules. mSiO₂ not only enhances the dispersity of the active phase and generates more active sites for superior catalytic activity but also improves resulted selectivity and cyclic lifespan for enhanced interaction. And high adsorption capacity of mSiO₂ also increases the reactant molecule enrichment. In addition, mesoporous feature of the mSiO₂ pore wall can ensure diffusion of the substrate molecules and prevent leaching of active components. Thus, related investigation and application have been rapidly growing in the past decades. In this review, the development of mesoporous silica based catalysts on preparation, modification, pore size tune and energy-related applications, especially in hydrogenation reaction, esterification reaction, hydrogen production by alkane dry reforming and alcohol steam reforming and photocatalytic water splitting, is introduced in detail and the design ideas, preparation strategies and corresponding mechanism of different composite catalysts are discussed.     

Yield,water use efficiency and economic analysis of energy sorghum in South Texas

Yields, water use efficiency and economic returns (net farm revenues) of biomass sorghum [Sorghum bicolor (L.) Moench] were investigated over two years (2012 and 2014) under limited water resource conditions. Energy sorghum was grown under four water supply regimes: rain-fed (or dry-land, level 1), 50% (level 2), 75% (level 3) and 100% (level 4) of crop evapotranspiration rates (% ET_c). Biomass yields ranged from 5.8 to 16.6 Mg ha⁻¹ (dry weight) after 126 days of growth. Average water use efficiencies ranged from 3.95 kg m⁻³ to 23.4 kg m⁻³. Net return was approximately 410 $ ha⁻¹ with water depths above 400 ha-mm. These results suggest that it is possible to obtain more than 60 Mg ha⁻¹ of sorghum biomass (wet basis) with at least 425 mm of water. While biomass yield under irrigation was greater than rain-fed conditions, there were no significant differences among irrigation treatments. Biomass chemical composition did not differ significantly among water treatments suggesting that biofuel quality would not be affected by water deficits.     

Yield potential and stand establishment for 20 candidate bioenergy feedstocks

Here we assess 20 bioenergy crop accessions across 10 species, and examine the influence of weed management and annual harvest treatments over three growing seasons in Virginia and one season in Kentucky. Species in this study include: Andropogon gerardii, Arundo donax, Miscanthus × giganteus (sterile triploid and seeded tetraploid), Miscanthus sinensis (ornamental and naturalized), Miscanthus sacchariflorus, Panicum virgatum, Phalaris arundinacea, Saccharum sp., Sorghum bicolor and the unconventional choice of Sorghum halepense. There was a large difference in yield between locations at the end of the planting year, with all accessions producing equivalent or greater biomass in Kentucky. Weed management did not impact yield in the establishment year, as biomass was predictably low. After the third growing season, only A. gerardii and two accessions of naturalized M. sinensis had noticeable reductions in yield due to competition from weeds. After three growing seasons, we obtained the highest yields from M. × giganteus (63, 51 and 39 Mg ha⁻¹ for ‘Illinois’, ‘PowerCane’ and ‘Nagara’ varieties, respectively), naturalized accessions of M. sinensis (54 Mg ha⁻¹), and A. donax (39 Mg ha⁻¹), using traditional cropping practices. Few accessions had low establishment rates limiting overall yields (<10 Mg ha⁻¹); however, when aboveground biomass was calculated on an individual plant basis, yields were comparable to high yielding species, encouraging further examination at higher population densities. Our results indicate that site characteristics such as soil parameters and water availability may be more important for yield than weed competition, especially over time.     

Productivity of harvesting dense birch stands for bioenergy

Marginal lands could be utilized for increasing energy biomass production independent of industrial roundwood procurement. Dedicated energy biomass production systems on such sites would be based on low stand establishment cost, clear-cutting at an early stage, and coppice regeneration. Harvesters designed for the processing of industrial roundwood are inefficient or too costly to use in small-diameter and dense stands, while insufficient cutting capacity and uneven space distribution of trees limit the use of modified agricultural harvesters developed for short-rotation woody-crop plantations (e.g. willow). We constructed time consumption models for clear-cutting and forwarding of whole trees from un-thinned, small-diameter stands. The data originated from naturally afforested downy birch-dominated stands located in a cutaway peat production area in northern Finland. Stand age varied from 14 to 29 years and stand density was 5150–160,250 trees per hectare. In clear-cutting, a medium-sized forest harvester equipped with an accumulating felling head fitted with a circular saw disc was used, and subsequent forwarding was done using a modified medium-sized forwarder. Cutting productivity was 3–11oven-dry tons (ODt) per effective hour (E₀-h), and was highly dependent on stand characteristics (e.g. mean whole-tree volume). At a distance of 300 m, for example, the productivity of forwarding in the time study plots was 6.7–10.4 ODt E₀-h⁻¹. Our study indicates that energy biomass can be harvested from young downy birch thickets efficiently by clear-cutting with appropriate machinery.     

Biomass as an energy source

Bioenergy is a source of sustainable energy. On the world stage biomass provides 10.6% of global primary energy supplies. There are several drivers for its development in Australia. The paper discusses the bioenergy technologies of combustion (including co-firing), gasification, pyrolysis and anaerobic digestion, noting some key projects that have been developed under each category. Australia's Mandatory Renewable Energy Target and its requirements have stimulated renewable energy, and notably bioenergy projects. The status and development of liquid biofuels are also covered. The paper also discusses bioenergy supporting activities, such as the development of a national bioenergy atlas, participation in the International Energy Agency's Bioenergy program, a major biomass energy production report and the function and operation of Bioenergy Australia.     

Simultaneous coproduction of hydrogen and methane from sugary wastewater by an “ACSTRH–UASBMet” system

A two-phase “ACSTR_H–UASB_Met” system has been investigated at the stepwise decreased HRT for the simultaneous production of hydrogen and methane in this study. Hydrogen could be continuously produced from the two-phase hydrogen fermentation of sugary wastewater in ACSTR and effluents from hydrogen fermentation were converted into methane in UASB reactor. At optimum conditions (HRT_H: 5 h, HRT_Met: 15 h), the highest hydrogen production rate of 5.69 (±0.06) mmol L⁻¹ h⁻¹ was obtained from sugary wastewater and methane was continuously produced from effluents of hydrogen fermentation with a production rate of 3.74 (±0.13) mmol L⁻¹ h⁻¹. The total bioenergy recovery by coproduction of hydrogen and methane from sugary wastewater reached 19.37 W and a total of 92.41% of substrate was converted to the biogas (hydrogen and methane) with two-phase anaerobic fermentation.