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- ItemSimulating second-generation herbaceous bioenergy crop yield using the global hydrological model H08 (v.bio1)(Katlenburg-Lindau : Copernicus, 2020) Ai, Zhipin; Hanasaki, Naota; Heck, Vera; Hasegawa, Tomoko; Fujimori, ShinichiroLarge-scale deployment of bioenergy plantations would have adverse effects on water resources. There is an increasing need to ensure the appropriate inclusion of the bioenergy crops in global hydrological models. Here, through parameter calibration and algorithm improvement, we enhanced the global hydrological model H08 to simulate the bioenergy yield from two dedicated herbaceous bioenergy crops: Miscanthus and switchgrass. Site-specific evaluations showed that the enhanced model had the ability to simulate yield for both Miscanthus and switchgrass, with the calibrated yields being well within the ranges of the observed yield. Independent country-specific evaluations further confirmed the performance of the H08 (v.bio1). Using this improved model, we found that unconstrained irrigation more than doubled the yield under rainfed condition, but reduced the water use efficiency (WUE) by 32 % globally. With irrigation, the yield in dry climate zones can exceed the rainfed yields in tropical climate zones. Nevertheless, due to the low water consumption in tropical areas, the highest WUE was found in tropical climate zones, regardless of whether the crop was irrigated. Our enhanced model provides a new tool for the future assessment of bioenergy–water tradeoffs.
- ItemSpatially explicit analysis identifies significant potential for bioenergy with carbon capture and storage in China([London] : Nature Publishing Group UK, 2021) Xing, Xiaofan; Wang, Rong; Bauer, Nico; Ciais, Philippe; Cao, Junji; Chen, Jianmin; Tang, Xu; Wang, Lin; Yang, Xin; Boucher, Olivier; Goll, Daniel; Peñuelas, Josep; Janssens, Ivan A.; Balkanski, Yves; Clark, James; Ma, Jianmin; Pan, Bo; Zhang, Shicheng; Ye, Xingnan; Wang, Yutao; Li, Qing; Luo, Gang; Shen, Guofeng; Li, Wei; Yang, Yechen; Xu, SiqingAs China ramped-up coal power capacities rapidly while CO2 emissions need to decline, these capacities would turn into stranded assets. To deal with this risk, a promising option is to retrofit these capacities to co-fire with biomass and eventually upgrade to CCS operation (BECCS), but the feasibility is debated with respect to negative impacts on broader sustainability issues. Here we present a data-rich spatially explicit approach to estimate the marginal cost curve for decarbonizing the power sector in China with BECCS. We identify a potential of 222 GW of power capacities in 2836 counties generated by co-firing 0.9 Gt of biomass from the same county, with half being agricultural residues. Our spatially explicit method helps to reduce uncertainty in the economic costs and emissions of BECCS, identify the best opportunities for bioenergy and show the limitations by logistical challenges to achieve carbon neutrality in the power sector with large-scale BECCS in China.
- ItemA Review of Biomass Briquette Binders and Quality Parameters(Basel : MDPI, 2022) Obi, Okey Francis; Pecenka, Ralf; Clifford, Michael J.The adverse effect of the use of fossil fuels on the environment and public health has given rise to a sustained renewable energy research and development. An important component of global renewable energy mix is the use of loose biomass, including agricultural and forestry residues, to produce solid fuels in the form of briquettes. Briquettes play a significant role in bioenergy mix in developing and developed countries. The production of biomass briquettes often entails the collection, transportation, storage, processing, and compaction of loose biomass that meet specific quality parameters. The densification process often involves the addition of binders to improve the cohesive strength of the briquette material. This paper surveys recent literature from 2012 to 2021 to establish the current state of research on the use of binders in briquette production; and reviews current parameters used in assessing the quality of biomass briquettes with focus on mechanical and handling properties. While a number of quality parameters were identified, their assessment methodologies varied widely in the literature, thus necessitating standardization for comparability purposes. The review also includes factors affecting the wide production and adoption of biomass briquettes in most developing economies and proposes ways of overcoming the bottlenecks.
- ItemBriquetting of Poplar Wood from Short Rotation Coppice—The Effects of Moisture Content and Hammer Mill Screen Size(Basel : MDPI, 2023) Obi, Okey Francis; Pecenka, RalfStudies on the use of biomass from short rotation coppices for briquette production as a sustainable biofuel have been scarce in the literature. This study investigated the effects of two process variables, hammer mill screen size at three levels (5.3, 10.3, and 25.4 mm) and moisture content at three levels (13.6, 19, and 25% (w.b.)), on the properties of briquettes from poplar Max-4 trees. The whole tree was divided into two fractions, the crown and the stem, and briquettes were produced from them. The effects of the variables on compressed density, relaxed density, relaxation ratio, and the shatter index of the briquettes were analyzed. The results showed that the combined interaction of the variables had no significant effects (p > 0.05) on the compressed density, relaxed density, and relaxation ratio of the briquettes. However, hammer mill screen size and moisture content both significantly influenced the shatter index irrespective of the tree fraction (p < 0.05). Hammer mill screen sizes of 5.3 and 10.3 mm at moisture contents of 13.6 and 19% (w.b.) resulted in good quality briquettes across the properties investigated for both the crown and stem poplar tree fractions. This study shows that high-quality briquettes can be produced from poplar Max-4 woody biomass.
- ItemInvestigation of the Effects of Torrefaction Temperature and Residence Time on the Fuel Quality of Corncobs in a Fixed-Bed Reactor(Basel : MDPI, 2022) Orisaleye, Joseph I.; Jekayinfa, Simeon O.; Pecenka, Ralf; Ogundare, Adebayo A.; Akinseloyin, Michael O.; Fadipe, Opeyemi L.Biomass from agriculture is a promising alternative fuel due to its carbon-neutral feature. However, raw biomass does not have properties required for its direct utilization for energy generation. Torrefaction is considered as a pretreatment method to improve the properties of biomass for energy applications. This study was aimed at investigating the effects of torrefaction temperature and residence time on some physical and chemical properties of torrefied corncobs. Therefore, a fixed-bed torrefaction reactor was developed and used in the torrefaction of corncobs. The torrefaction process parameters investigated were the torrefaction temperature (200, 240, and 280 °C) and the residence time (30, 60, and 90 min). The effects of these parameters on the mass loss, grindability, chemical composition, and calorific value of biomass were investigated. It was shown that the mass loss increased with increasing torrefaction temperature and residence time. The grinding throughput of the biomass was improved by increasing both the torrefaction temperature and the residence time. Torrefaction at higher temperatures and longer residence times had greater effects on the reduction in particle size of the milled corncobs. The calorific value was highest at a torrefaction temperature of 280 °C and a residence time of 90 min. The energy yield for all treatments ranged between 92.8 and 99.2%. The results obtained in this study could be useful in the operation and design of torrefaction reactors. They also provided insight into parameters to be investigated for optimization of the torrefaction reactor.
- ItemBioenergy for climate change mitigation: Scale and sustainability(Oxford : Wiley-Blackwell, 2021) Calvin, Katherine; Cowie, Annette; Berndes, Göran; Arneth, Almut; Cherubini, Francesco; Portugal‐Pereira, Joana; Grassi, Giacomo; House, Jo; Johnson, Francis X.; Popp, Alexander; Rounsevell, Mark; Slade, Raphael; Smith, PeteMany global climate change mitigation pathways presented in IPCC assessment reports rely heavily on the deployment of bioenergy, often used in conjunction with carbon capture and storage. We review the literature on bioenergy use for climate change mitigation, including studies that use top-down integrated assessment models or bottom-up modelling, and studies that do not rely on modelling. We summarize the state of knowledge concerning potential co-benefits and adverse side effects of bioenergy systems and discuss limitations of modelling studies used to analyse consequences of bioenergy expansion. The implications of bioenergy supply on mitigation and other sustainability criteria are context dependent and influenced by feedstock, management regime, climatic region, scale of deployment and how bioenergy alters energy systems and land use. Depending on previous land use, widespread deployment of monoculture plantations may contribute to mitigation but can cause negative impacts across a range of other sustainability criteria. Strategic integration of new biomass supply systems into existing agriculture and forest landscapes may result in less mitigation but can contribute positively to other sustainability objectives. There is considerable variation in evaluations of how sustainability challenges evolve as the scale of bioenergy deployment increases, due to limitations of existing models, and uncertainty over the future context with respect to the many variables that influence alternative uses of biomass and land. Integrative policies, coordinated institutions and improved governance mechanisms to enhance co-benefits and minimize adverse side effects can reduce the risks of large-scale deployment of bioenergy. Further, conservation and efficiency measures for energy, land and biomass can support greater flexibility in achieving climate change mitigation and adaptation.
- ItemGlobal scenarios of irrigation water abstractions for bioenergy production: a systematic review(Munich : EGU, 2021) Stenzel, Fabian; Gerten, Dieter; Hanasaki, NaotaMany scenarios of future climate evolution and its anthropogenic drivers include considerable amounts of bioenergy as a fuel source, as a negative emission technology, and for providing electricity. The associated freshwater abstractions for irrigation of dedicated biomass plantations might be substantial and therefore potentially increase water limitation and stress in affected regions; however, assumptions and quantities of water use provided in the literature vary strongly. This paper reviews existing global assessments of freshwater abstractions for bioenergy production and puts these estimates into the context of scenarios of other water-use sectors. We scanned the available literature and (out of 430 initial hits) found 16 publications (some of which include several bioenergy-water-use scenarios) with reported values on global irrigation water abstractions for biomass plantations, suggesting water withdrawals in the range of 128.4 to 9000 km3 yr−1, which would come on top of (or compete with) agricultural, industrial, and domestic water withdrawals. To provide an understanding of the origins of this large range, we present the diverse underlying assumptions, discuss major study differences, and calculate an inverse water-use efficiency (iwue), which facilitates comparison of the required freshwater amounts per produced biomass harvest. We conclude that due to the potentially high water demands and the tradeoffs that might go along with them, bioenergy should be an integral part of global assessments of freshwater demand and use. For interpreting and comparing reported estimates of possible future bioenergy water abstractions, full disclosure of parameters and assumptions is crucial. A minimum set should include the complete water balances of bioenergy production systems (including partitioning of blue and green water), bioenergy crop species and associated water-use efficiencies, rainfed and irrigated bioenergy plantation locations (including total area and meteorological conditions), and total biomass harvest amounts. In the future, a model intercomparison project with standardized parameters and scenarios would be helpful.
- ItemEffects of Feeding Speed and Temperature on Properties of Briquettes from Poplar Wood Using a Hydraulic Briquetting Press(Basel : MDPI, 2023) Orisaleye, Joseph I.; Jekayinfa, Simeon O.; Dittrich, Christian; Obi, Okey F.; Pecenka, RalfBiomass has a high potential to contribute towards resolving the energy deficit. Processing biomass into solid fuels enhances its use in various bioenergy conversion technologies. The quality of densified biomass depends on several variables. The investigation of the effect of densification parameters on briquette quality is necessary for process optimization. This study investigates the influence of die temperature (100, 120, 140 °C) and feeding speed (2.4, 2.9, 3.3 mm s−1) on the quality of briquettes produced from poplar using a hydraulic biomass briquetting machine. The density of the briquettes ranged between 746.7 and 916.8 kg m−3, the mechanical durability ranged from 97.4 to 98.4%, and the water resistance index was between 91.6 and 96.1%. The results show that the temperature was statistically significant (p < 0.05) on the density, mechanical durability and water resistance of biomass briquettes. The feeding speed was statistically significant (p < 0.05) on the density and water resistance. The interaction of temperature and feeding speed was statistically significant (p < 0.05) on all properties considered. The results obtained in this study are useful for optimizing the quality of briquettes produced using the hydraulic piston press.