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The study aimed to determine the above-ground biomass (AGB) of tropical deciduous forests in Central India using field-based techniques and spaceborne quad-pol ALOS PALSAR-2 L-band and dual-pol Sentinel 1A C-band synthetic aperture radar (SAR). Field sampling based on 73 forested grids exhibited a diverse forest composition in the Satpura Tiger Reserve (STR) with a total of 54 tree species of which 31.48% species were IUCN Red-Listed. The forests were highly diverse (H′=3.22) with a low concentration of dominance (CD = 0.06) and a quite high species evenness (E = 0.81). The sensitivity and correlation between field-based AGB and SAR backscatter in STR were highest in cross-polarization due to its higher sensitivity to the vegetation structure in both L- and C-band SAR, where L-VH based AGB estimates were found more accurate (RMSE:5.17%). The study provided vital information for setting up strategies for biodiversity conservation, enhancing forest productivity, and restoring wildlife habitats. [ABSTRACT FROM AUTHOR]

A few decades ago, hydroelectric projects were considered a clean source of energy. The present study aims to assess the biomass and soil carbon (C) stock in the hydroelectric catchment in India and further, its implications to mitigate GHG emissions. The estimation depicts the low 'C' stock in the reservoir's catchment in comparison to reservoirs located globally in the same eco-region which will ultimately result in lower GHG emission in the future. Moreover, estimated total carbon density of the forest species was found as 54.92 ± 18.07 MgC.ha−1 while mean SOC was 79.64 ± 19.32 MgC.ha−1. The average total 'C' stock of Tehri hydroelectric reservoir's catchment was estimated as 134.56 MgC.ha−1. Moreover, ratios (total flooded carbon/installed capacity) comprised between 4 and304 kgC/W from the other reservoirs reported globally. These ratios are higher than the Tehri reservoir (0.28 kgC/W) as flooded area of Tehri reservoir during impoundment was 52 km2. Thus, Tehri reservoir was found to emit less GHG in time to come. The present study helps the hydropower industries, policymakers, and environmentalists in designing the catchment area treatment plan to minimize the negative impact of GHG on climate change. [ABSTRACT FROM AUTHOR]

Agroforestry has great potential for carbon (C) sequestration among different land uses of the Himalayan region, India. However, our knowledge of C sequestration in particular, agroforestry system around the world is poor. Therefore, we conducted a study to understand biomass accumulation and carbon allocation in different components of the agroforestry system. The highest stem biomass was recorded in Eucalyptus tereticornis (69.43 ± 0.90 Mg ha-1), branch biomass in Populus deltoids (5.04 ± 0.35 Mg ha-1), leaf biomass also in P. deltoids (2.21 ± 0.12 Mg ha-1), and root biomass in Albizia procera (14.01 ± 0.44 Mg ha-1). The highest (81.01%) C allocation was recorded in the stem of Toona ciliate, branch of P. deltoids (5.73%), leaves of E. tereticornis (2.93%) and root of Anthocephalus cadamba (16.83%). The highest CO2 mitigation (160.5 ± 2.55 Mg CO2 ha-1) and C sequestration (45.33 ± 0.60 Mg ha-1) were recorded in E. tereticornis. The highest wheat crop biomass (11.85 ± 0.23 Mg ha-1) and C stock (3.59 ± 0.05 Mg ha-1) were recorded in P. deltiodes. However, soil carbon stock was recorded in E. tereticornis (37.5 ± 3.52 Mg ha-1). Thus, trees on farmlands with crops are suitable for biomass production and C allocation in different components under changing climatic scenarios. [ABSTRACT FROM AUTHOR]

Aims: Root system responses to the limitation of either nitrogen (N) or phosphorus (P) are well documented, but how the early root system responds to (co-) limitation of one (N or P) or both in a stoichiometric framework is not well-known. In addition, how intraspecific competition alters plant responses to N:P stoichiometry is understudied. Therefore, we aimed to investigate the effects of N:P stoichiometry and competition on root system responses and overall plant performance. Methods: Plants (Hordeum vulgare L.) were grown in rhizoboxes for 24 days in the presence or absence of competition (three vs. one plant per rhizobox), and fertilized with different combinations of N:P (low N + low P, low N + high P, high N + low P, and high N + high P). Results: Shoot biomass was highest when both N and P were provided in high amounts. In competition, shoot biomass decreased on average by 22%. Total root biomass (per plant) was not affected by N:P stoichiometry and competition but differences were observed in specific root length and root biomass allocation across soil depths. Specific root length depended on the identity of limiting nutrient (N or P) and competition. Plants had higher proportion of root biomass in deeper soil layers under N limitation, while a greater proportion of root biomass was found at the top soil layers under P limitation. Conclusions: With low N and P availability during early growth, higher investments in root system development can significantly trade off with aboveground productivity, and strong intraspecific competition can further strengthen such effects. [ABSTRACT FROM AUTHOR]

Abstract: Oxymethylene ethers (OMEs) are important diesel additives because of their ability to reduce soot loading, particulate matter (PM) emissions, and NOx emissions. Some research has been undertaken on the feasibility of producing OMEs from biomass but there is no techno‐economic assessment of OME production from biomass. In this study, we estimate the unit cost to produce OMEn (n = 1–8) from three different biomass types common to western Canada: whole‐tree woodchips, forest residues, and wheat straw. The techno‐economic model uses the OME production simulation results for 500 MT day−1 of dry biomass. The simulation results show that 97.70, 98.86, and 99.80 MT day−1 of OME1–8 can be produced from whole‐tree woodchips, forest residues, and wheat straw, respectively. The costs of producing OME per liter over 20 years of production are $1.93 ±0.15/L, $1.68 ±0.14/L, and $1.66 ±0.13/L, respectively, at a 95% confidence level for whole‐tree woodchips, forest residues, and wheat straw biomass. The sensitivity analysis results show that the internal rate of return, OME yield, capital cost, and biomass delivery cost significantly influence OME unit price. The production price versus capacity profile reveals that the optimum minimum price can be obtained at a plant capacity of 4000 MT day−1 of biomass; beyond this, the increase in capacity does not result in any appreciable decrease in production price. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Microbial processes mediated by soil enzymes are crucial in soil organic matter decomposition, resulting in release of nutrients that become available for plant and microbial uptake. Therefore, it is crucial to know the sensitivity of enzyme activities (EA) along soil depths at distinct plant vegetation stages, and how the availability of mineral nitrogen (N) alters EA. We studied effects of N fertilization (0 and 160 kg N ha −1 ), soil depth (0–35 cm), and plant-phenological stage (silking and maturity) on microbial biomass C (C mic ) and potential activities of C-, N- and P-acquiring enzymes in the field under Zea mays L. Nitrogen fertilization increased shoot biomass by more than 80% compared to unfertilized plants. Maize roots triggered increases in C mic and EA for all measured enzymes compared to bare fallow. Stimulating effect of plant roots on EA was enzyme specific and stronger at silking than maturity stage of maize. The down-regulating effect of N fertilization on EA involved in acquiring N was most pronounced on the activity of L-leucine aminopeptidase and β-1,4- N -acetylglucosaminidase. Soil depth was the primary determinant of EA, explaining up to 51% of the variation. Depth-dependent EA changes were stronger in rooted soil. A pronounced biotic control on EA was demonstrated by higher EA in rooted soil than in bare fallow. This confirmed root-mediated microbial activation. Stronger effect of silking vs. maturity stage on EA indicated that actively growing roots fuel microorganisms via root-derived organics. Thus, soil depth and plant roots were major factors controlling microbial activity in arable soil. [ABSTRACT FROM AUTHOR]

Due to the scarcity of fossil fuels and to population increases, there is an urgent need for renewable energy sources that can replace petroleum-derived fuels. Lignocellulosic biomass, a renewable resource, can be converted to bio-oil by fast pyrolysis and further upgraded to renewable diesel through hydroprocessing. The upgrading of oil by fast pyrolysis is the main focus of this paper. Bio-oil has a higher energy density and heating value than biomass, but it cannot be used in place of petro-diesel as it is highly unstable, polar, and immiscible with hydrocarbons. Thus upgrading is necessary as it removes oxygen-containing compounds from bio-oil. Hydroprocessing was chosen for this review paper as the method of upgrading bio-oil because there are hydrotreating units in place in refineries. To upgrade bio-oil, hydrodeoxygenation (HDO) in the presence of both a catalyst and hydrogen can replace hydrodesulfurization (the removal of sulfur compounds from crude oil). A sulfided NiMo/CoMo catalyst supported on gamma alumina is used as a benchmark catalyst for a hydrodesulfurization reaction in refineries and is considered the reference catalyst for HDO in the production of renewable diesel. The properties of renewable diesel made through hydroprocessing are similar to those of petro-diesel. Catalyst deactivation and techno-economic assessments of the whole pathway are areas that need more attention before renewable diesel can be commercialized. This review paper concentrates on the reaction mechanism in bio-oil upgrading, process parameters, and the limitations of hydroprocessing technology. This paper will be helpful for further modeling of techno-economic analysis in renewable diesel production from lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

The hydropower reservoirs, considered as a green source of energy, are now found to emit significant quantities of greenhouse gas (GHG) to the atmosphere. This article attempts to predict the vulnerability of Tehri reservoir, India to GHG emissions using the GHG risk assessment tool (GRAT). The GRAT is verified with experimental GHG fluxes. The annual mean CO2fluxes from diffusion, bubbling, and degassing were 425.93 ± 122.50, 4.81 ± 1.33, and 7.01 ± 2.77 mg m−2d−1, whereas CH4fluxes were 23.11 ± 7.08, 4.79 ± 1.08, and 7.41 ± 4.50 mg m−2d−1, respectively, during 2011–12. The model found that Tehri reservoir emitted higher CO2and CH4(i.e., 790 mg m−2d−1and 64 mg m−2d−1, respectively) in 2011, which came within vulnerability range causing more climate change impact. By the year 2015, it would scale down to medium risks necessitating no further assessment of GHG. Significant difference between predicted and experimental GHG emission are assessed, which may be due to insufficient data, spatial and temporal variations, decomposition of flooded biomass, limitation of GRAT model, and inadequate methodology. The study reveals that GHG emission from Tehri reservoir is less than predicted by the GRAT. [ABSTRACT FROM PUBLISHER]

Pipeline hydro-transport, an economically viable means of delivering large volumes of biomass, can replace conventional modes of transport – road, rail, and river - to improve the economy of pulp and paper mills, as well as bio-based energy facilities. This paper is a review of experimental and theoretical studies conducted by various sectors on the transport of wood and non-wood biomass-water mixtures (slurries) in pipes. The aims were to collect technical challenges, governing mechanical equations, and associated economic issues, as well as to identify the gaps in knowledge in the area. There have been several experiments conducted on pipeline hydro-transport of wood chips over a wide range of pipeline materials, lengths, and diameters. However, pipeline transport of non-wood agricultural residue slurries, as well as the performance of the centrifugal slurry pump handling such mixtures, has recently been investigated in a single lab-scale pipeline facility. Several researchers have proposed empirical correlations to estimate friction loss in wood chip slurries flowing in pipes and also recommended technically and economically optimum pumping velocities. Those correlations, however, are reported to come with noticeable deviations from one another and from experimental measurements. One empirical correlation has been also proposed to predict, with an uncertainty of less than 10%, the longitudinal pressure gradients in pipeline hydro-transport of agricultural residue biomass. All the experimental measurements and empirical correlations based some studies on the economic feasibility of pipelining wood chip-water mixtures. These studies proved the concept of economy of scale to be highly applicable to biomass pipeline systems. [ABSTRACT FROM AUTHOR]

Pipeline hydrotransport of agricultural residue in a carrier liquid could be an economically viable alternative to replace truck delivery of biomass materials, as well as encouraging the increase in scale of bio-refineries. The feasibility of this concept, together with friction loss behaviour and corresponding mechanisms of biomass slurry flows through pipelines, was previously studied by the authors. A 50 mm diameter, 25 m long pipeline facility was used to measure the longitudinal pressure gradient of wheat straw and corn stover slurries over a range of particle dimensions, slurry solid mass fractions, and slurry velocities. Econometric software and a nonlinear least square regression model were used to analyse the measured pressure gradients and an empirical correlation was proposed to predict slurry pressure gradients as a function of slurry specifications and operating conditions. The correlation was then modified using scale-up methods to account for the effects of pipe diameter. The pressure gradient was found to be proportional to the pipe diameter to the power of −1.2. The final correlation was able to predict the longitudinal pressure gradient of the flow of agricultural residues (i.e., non-wood fibres) as biomass slurries in pipes and, with a small uncertainty (<10%), could be applied to design commercial pipelines to hydraulically transport various agricultural residue biomass slurries. This knowledge of the slurry flow pressure gradient is essential to specify slurry pumps, determine the number of booster stations, and estimate the capital and operational costs of a slurry pipeline. [ABSTRACT FROM AUTHOR]

Abstract: Bio-oil, produced by fast pyrolysis of biomass, has high energy density compared to ‘as received’ biomass. The study assesses and compares the cost of transportation ($/liter of bio-oil) of bio-oil by pipeline and truck. The fixed and variable cost components of transportation of bio-oil at a pipeline capacity of 560m3/day and to a distance of 100km are 0.0423$/m3 and 0.1201$/m3/km, respectively. Pipeline transportation of bio-oil costs less than transportation by liquid tank truck (load capacity 30m3) and super B-train trailer (load capacity 60m3) above pipeline capacities of 1000 and 1700m3/day, respectively. When transportation distance is greater than 100km, bio-oil must be heated at booster stations. When transporting bio-oil by pipeline to a distance of 400km, minimum pipeline capacities of 1150 and 2000m3/day are required to compete economically with liquid tank trucks and super B-train tank trailers, respectively. [Copyright &y& Elsevier]

Abstract: Minimum production cost and optimum plant size were determined for pellet plants using agricultural biomass residue from wheat, barley and oats. Three scenarios involving minimum, average and maximum yields of straw were considered for developing a techno-economic model. The life cycle cost of producing pellets in Western Canada was estimated. The economically optimum size of production plant for the three yield scenarios in tonne year−1 were 70,000, 150,000 and 150,000, respectively. The corresponding costs of production per tonne are $170.89, $129.42 and $122.17, respectively. However, the cost of pellets does not change much for capacities over 70,000tonne year−1 for both the average and maximum yields. The optimum size is same for both average and maximum yield cases. Sensitivity analyses have showed that the total cost of pellet production is most sensitive to field cost followed by transportation cost. Currently, the cost of energy from agri-pellets is higher than that of energy from natural gas. [Copyright &y& Elsevier]

Biomass is nearly carbon neutral and can be used for the production of various liquid fuels and chemicals. Decisions on biomass utilization should be based on the most economical and mature route. This study analyzes mountain pine beetle (MPB) killed wood as the feedstock for production of bio-ethanol and bio-oil and compares it with the direct combustion route to produce electricity. The MPB infestation of British Columbia’s (BC), a western province of Canada, forest has reached an epidemic proportion and is spread over an area of 10 millionha. According to the current estimates of BC‘s Ministry of Forests and Range, about 1 billion m3 of trees would be killed by MPB by 2013. This infestation would result in large scale loss of jobs and the standing dead trees are a fire hazard and if left unharvested will decay and release carbon back to the atmosphere. The cost of bio-ethanol production from a 2100dry tonne/day plant using the infested wood for two locations (one remote and other near the industry) in BC is in the range of C$0.37–C$0.40/l (C$1.40–C$1.51/gallon). Similarly, cost of bio-oil production from a 220dry tonne/day plant using the infested wood for same two locations in BC is in the range of C$0.27–C$0.29/l (C$1.02–C$1.09/gallon). The cost of producing electricity using this bio-oil is above C$100/MWh which is higher than the current power price in BC. This cost is also higher than the cost of production of electricity by direct combustion of infested wood in a boiler (C$68–C$74/MWh). [Copyright &y& Elsevier]

Abstract: Biomass is considered carbon neutral, and displacement of fossil fuel-based power by biomass-based power is one means to mitigate greenhouse gases. Large forest areas in British Columbia (BC), Canada, are infested by the mountain pine beetle (MPB). Dead wood from the infestation is expected to vastly exceed the ability of the pulp and lumber industry to utilize it; current estimates are that 200–600 millionm3 of wood will remain unharvested over the next 20 years. Regions where the damaged wood is not harvested will experience loss of jobs in the forestry sector, increased risk of forest fire hazard, carbon emissions from burned or decaying wood, and uncertainty about timing of replanting since this usually occurs at harvest. This paper reports the results of a detailed preliminary techno-economic analysis of producing power from MPB killed wood. Power plant size and location are critical factors affecting overall power cost. Overall cost of power rises steeply at sizes below 300MW net power output. By locating the power plant in an area of high infestation, transportation distances can be minimized. A 300MW power plant would consume 64millionm3 of wood over a 20-year lifetime, and hence is a significant sink for otherwise unharvestable wood. Cost estimates are based on harvesting of whole dead trees with roadside chipping and transport to a central power plant located in either the Nazko or Quesnel regions of BC. A circulating fluidized bed boiler with a conventional steam cycle is a currently available technology demonstrated at 240MW in Finland. The estimated power cost is $68 to $74 per MWh, which is competitive with other “green power” values in BC. Given recent values of export power in the Pacific Northwest, a 300MW MPB power plant is viable with a carbon credit below $15 per tons of CO2. [Copyright &y& Elsevier]

Abstract: This study develops cost, energy input and carbon emissions for a number of switchgrass supply options. The Integrated Biomass Supply Analysis and Logistics (IBSAL) model developed at Oak Ridge National Laboratory is used to evaluate the delivery systems. Three biomass collection systems: baling, loafing and ensiling are evaluated. The number and operational performance of equipment are specified to complete collection operations within 120days of harvest after August 1. Bales are stacked and tarped on the farm side. The transport of biomass from the farm side to a biorefinery takes place over a full year cycle, i.e. 365days. Supply quantities range from 454 to 4540 dry tonnes/day (500–5000 dry tons/day). Delivered costs to a biorefinery with capacity of 1814 dry tonnes/day (2000 dry tons/day) are: $44–$47/dry tonne for delivered bales (round and square); $37/dry tonne for delivered loafs (size 2.4m×3.6m×6m); $40/dry tonne for chopped biomass; and $48/dry tonne for ensiled chops. These costs do not include any payment to the farmers or switchgrass farming cost. Based on the data from literature, the switchgrass farming cost can range from $30 to $36/dry tonne. These costs would be additional to the switchgrass collection and transportation cost. Switchgrass collection is generally less expensive than collection of straw or corn stover because of the assumed high yield of 11 dry tonnes/ha and a denser biomass. Energy consumption for delivery systems at this capacity ranges from 4.8% to 6.3% of the energy content of switchgrass. Additional 1% of the energy content of switchgrass is consumed in its farming. At 1814 dry tonnes/day (2000 dry tons/day) capacity, greenhouse gas emissions ranges from 75 to 100kg of CO2/dry tonne of switchgrass delivered. [Copyright &y& Elsevier]

Abstract: This paper describes the framework development of a dynamic integrated biomass supply analysis and logistics model (IBSAL) to simulate the collection, storage, and transport operations for supplying agricultural biomass to a biorefinery. The model consists of time dependent events representing the working rate of equipment and queues representing the capacity of storage structures. The discrete event and queues are inter-connected to represent the entire network of material flow from field to a biorefinery. Weather conditions including rain and snow influence the moisture content and the dry matter loss of biomass through the supply chain and are included in the model. The model is developed using an object oriented high level simulation language EXTEND™. A case of corn stover collection and transport scenario using baling system is described. [Copyright &y& Elsevier]

The power cost and optimum plant size for power plants using three biomass fuels in western Canada were determined. The three fuels are biomass from agricultural residues (grain straw), whole boreal forest, and forest harvest residues from existing lumber and pulp operations (limbs and tops). Forest harvest residues have the smallest economic size, 137 MW, and the highest power cost, $63.00 MWh−1 (Year 2000 US$). The optimum size for agricultural residues is 450 MW (the largest single biomass unit judged feasible in this study), and the power cost is $50.30 MWh−1. If a larger biomass boiler could be built, the optimum project size for straw would be 628 MW. Whole forest harvesting has an optimum size of 900 MW (two maximum sized units), and a power cost of $47.16 MWh−1 without nutrient replacement. However, power cost versus size from whole forest is essentially flat from 450 MW ($47.76 MWh−1) to 3150 MW ($48.86 MWh−1), so the optimum size is better thought of as a wide range.None of these projects are economic today, but could become so with a greenhouse gas credit. All biomass cases show some flatness in the profile of power cost vs. plant capacity. This occurs because the reduction in capital cost per unit capacity with increasing capacity is offset by increasing biomass transportation cost as the area from which biomass is drawn increases. This in turn means that smaller than optimum plants can be built with only a minor cost penalty. Both the yield of biomass per unit area and the location of the biomass have an impact on power cost and optimum size. Agricultural and forest harvest residues are transported over existing road networks, whereas the whole forest harvest requires new roads and has a location remote from existing transmission lines. Nutrient replacement in the whole forest case would make power from the forest comparable in cost to power from straw. [Copyright &y& Elsevier]

This review assesses biochar's potential as an electrode material for energy producing (microbial fuel cells (MFCs) and energy storage devices (supercapacitors, batteries). Conventional energy storage faces challenges due to resource scarcity, cost, and environmental impact. Biochar, derived from biomass using different processes like pyrolysis, hydrothermal treatment, and flash pyrolysis offers a renewable and eco-friendly alternative. It is easy to synthesize and has a high surface area, porous structure, reasonable conductivity, and chemical stability which make it a suitable material for bioelectrochemical processes and energy storage devices. It has shown promise in MFCs, supercapacitors, and batteries, enhancing electricity production, charge storage capacity, and stability. However, challenges persist in optimizing biochar preparation and scaling up production. To fully realize its benefits, further research is needed to understand underlying electrochemical processes and develop effective large-scale implementation strategies, leading to a greener and more sustainable energy landscape. [Display omitted] • Growing industrialization amplifies energy needs. • Biomass can be converted into biochar using pyrolysis and gasification. • Renewables tackle rising energy demand and necessitate efficient storage. • Batteries and supercapacitors are vital for high-density energy storage in electronics. • Biochar is an affordable eco-friendly electrode promoting sustainability. [ABSTRACT FROM AUTHOR]

Abstract Transporting biomass feedstock to biomass-based energy conversion facilities and optimally locating those facilities are among the main challenges in using biomass as a renewable source of energy. As part of the biomass collection procedure, agricultural residue is compacted into bales and amassed at biomass collection points (BCPs) for truck pick-up and delivery to conversion facilities. This study developed a framework for locating BCPs using an iterative process model in a geographic information systems (GIS) environment. The model used the biomass spatial distribution and road network maps and, via an iteration process, gave preference to zones with high biomass availability and short distance to the roads. The framework was applied to the particular case of optimally locating biomass-based conversion facilities in the Department of Santa Cruz in Bolivia, where there is a vast potential to use agricultural residues for energy production purposes. In total, 107 BCPs were located in the department with capacities ranging from 10,000 to 26,000 dry tonnes per collection point per year and an overall biomass collection capacity of 1.5 M dry tonnes per year. Exclusion, preference, suitability, and location-allocation analyses were then conducted using BCPs, facility candidate sites, and road network to locate seven optimal sites with capacities ranging from 23 to 83 MW which can be supplied by biomass ranging from 110,000 to 390,000 dry tonnes per year. The BCP framework developed here can improve the efficiency of collecting biomass and the accuracy of locating biomass-based facilities. Decision makers can use these results to expand biomass application in the energy sector in Bolivia. Highlights • A framework is developed for locating biomass collection points (BCPs). • GIS is used to locate BCPs and biomass-based energy conversion facilities. • BCPs are sited in areas with high biomass availability and close to roads. • Environmental, social and economic factors are considered in the analysis. • BCPs and seven facilities were optimally located in Santa Cruz, Bolivia. [ABSTRACT FROM AUTHOR]

Gasification has the potential to convert biomass into gaseous mixtures that can be used for hydrogen production. Thermal gasification and supercritical water gasification are commonly used thermochemical methods for conversion of biomass to hydrogen. Supercritical water gasification handles wet biomass, thus eliminating the capital cost-intensive drying step. Thermal gasification is considered as an alternative means of producing hydrogen from microalgae where biomass has to be dried before gasification. The authors developed techno-economic models for assessment of the production of hydrogen through supercritical gasification and thermal gasification processes. Techno-economic assessment was based on developed process models. Equipment was sized and costs were estimated using the developed process models, and the product value was determined assuming 20 years of plant life. The economic assessment of supercritical water and thermal gasification show that 2000 dry tonnes/day plant requires total capital investments of 277.8 M$ and 215.3 M$ for hydrogen product values of $4.59 ± 0.10/kg and $5.66 ± 0.10/kg, respectively. The relatively higher yield obtained in supercritical water gasification compared to thermal gasification results in lower product value of hydrogen for supercritical water gasification, thereby making it more desirable. This cost of hydrogen is about 4 times the cost of hydrogen from natural gas. The sensitivity analysis indicates that biomass cost and yield are the most sensitive parameters in the economics of the supercritical or thermal gasification process; this signifies the importance of algal biomass availability. The techno-economic assessment helps to identify options for the production of hydrogen fuel through these novel technologies. • The production of hydrogen from thermochemical algal conversion is assessed. • Data-intensive techno economic model is developed to determine the product value. • The cost of hydrogen from algal thermochemical processing varies from 4.59 to 5.66 $/kg. • The impact of CO 2 tipping fee on cost of hydrogen was assessed. [ABSTRACT FROM AUTHOR]

Abstract Although the transition towards replacing fossil fuels with renewable energies is increasing worldwide, using renewable resources and appropriate technologies are still challenging in developing countries. Biomass feedstock is receiving increased attention in Bolivia, a South American country, to increase access to renewable electricity and ensure a sustainable energy source. To develop biomass-based energy conversion facilities, it is critical to understand the biomass availability in Bolivia. This study quantified the sustainable agricultural residue biomass available throughout the country for energy generation purposes. The quantification process used statistical crop production information and correcting factors, including leftovers for soil conservation, animal feeding, etc. Following that, a geographic information system (GIS) was used to create maps showing the spatial distribution of residues in order to identify the municipalities that generate the largest volumes of agricultural residues. The results show that the major residues are from sugarcane, soybean, corn, rice, sorghum, and sunflower, which generate 3.8 M dry t/yr of biomass across the country. Most of the available biomass is generated in Santa Cruz, one of the country's nine departments, where biomass potential is estimated at 3.7 M dry t/yr. Ten neighboring municipalities in this department are identified as major residue producers with a biomass potential of 3.2 M dry t/yr, equivalent to an energy potential of 4.5 TWh and power generation of 722 MW, assuming 30% plant efficiency and 0.72 capacity factor. The biomass energy potential from these ten municipalities is equivalent to 50% of the annual electricity production. Moreover, it could supply energy to 58% of the population. These results demonstrate the vast potential in Bolivia to replace fossil fuels with residue biomass in producing energy. Graphical abstract fx1 Highlights • A sustainable biomass quantification is conducted in Bolivia. • Estimated annual agricultural residue potential in Bolivia is 3.8 M dry t. • The energy potential from agricultural residues in Bolivia is estimated at 5.3 TWh. • GIS was used to create spatial distribution maps of biomass across Bolivia. • Then municipalities in Santa Cruz generate 85% of total biomass availability. [ABSTRACT FROM AUTHOR]

Highlights • Impedancemetry technique is proposed to measure slurry flows critical velocities. • A 16-electrode impedancemetry device tested on a lab-scale pipeline facility. • Critical velocities of sand, wheat straw and wood chips slurry flows were measured. • The impedancemetry approach was found perfect replacement for traditional techniques. • Biomass flows critical velocities were found below industrial pumping velocities. Abstract Since the lower limit to operating velocities in slurry transport systems is influenced by deposition conditions, measuring the "deposition velocity" is an essential step in slurry pipelines' design and operation. This study proposes a new experimental technique in measuring deposition velocities in slurry pipeline transport called the high-frequency impedancemetry approach. This non-invasive technique of measuring electrical properties of substances, based on their frequency-dependent behavior, was applied using a 16-electrode impedancemetry device on a 25 m long closed-circuit pipeline to measure the deposition velocities of sand- and biomass–water mixture flows. Slurries of play and gravel sands, as well as wheat straw and wood chips biomass feedstock, were prepared over a range of concentrations (1.5–20 wt% dry-matter), and deposition velocities were measured over a wide range of operating velocities (0.04–4.5 m/s). Experimental measurements for sand–water mixtures were found to be in good agreement with empirical correlations derived previously through various analytical and mathematical techniques. In addition, for the first time, the deposition velocities for biomass–water mixtures were measured and found to be in the range of 0.21–0.8 m/s; surprisingly well below the common range of commercial pipelines' operating velocities, i.e., 1.4–3.0 m/s. [ABSTRACT FROM AUTHOR]

Hydrothermal processing, a thermochemical approach, is an excellent method of converting energy-rich biomass into useful products. This approach offers the advantage of handling biomass with relatively high moisture content by precluding an energy-intensive pretreatment step. Hydrothermal processing is of world-wide interest in view of depleting fossil-fuel reserves and increased environmental greenhouse gas emissions. There is potential to develop this novel technology at demonstration scale. This paper reviews the three hydrothermal technologies, namely hydrothermal liquefaction, gasification and carbonization, to provide insight into the likelihood of commercialization. The study discusses the role of different process parameters that have key impacts on the quality and yield of the desired products. This study also identifies the gaps in the literature including the need to establish a baseline to develop key process models and to perform a techno-economic assessment to get a better sense of the viability of the technology in future. [ABSTRACT FROM AUTHOR]

The life cycle energy consumption and greenhouse gas (GHG) emission performances of forest biomass-derived oxymethylene ether (OME) synthesis used as a diesel additive are analyzed in this study. OME, a new alternative liquid fuel, has great miscibility with conventional fuels like diesel. OME can reduce combustion emissions significantly when used as a diesel additive without any modification to the engine. A data-intensive spreadsheet-based life cycle assessment (LCA) model was developed for OME synthesis from woodchips derived from two different kinds of forest biomass, whole tree and forest residue. Woodchip harvesting, chip transportation, chemical synthesis of OME from biomass-derived syngas, OME transportation to blending, and vehicle combustion of this transportation fuel were considered in the system boundary. The results show that the whole tree pathway produces 27 g CO 2 eq/MJ of OME, whereas the forest residue pathway produces 18 g CO 2 eq/MJ of OME over 20 years of plant life. The difference is mainly due to some emissions-intensive operations involved in biomass harvesting and biomass transportation such as skidding, road construction, etc., in the whole tree pathway. Also, vehicle combustion was found to be the most GHG-intensive unit for both pathways. OME combustion in a vehicle accounts for about 77% and 83% of the total life cycle GHG emissions for the whole tree and forest residue pathways, respectively. This study also compares the diesel life cycle emission numbers with the life cycle emissions of OME derived from forest biomass, and it was observed that GHG emissions can be reduced by 20–21% and soot (black carbon) emissions can be reduced by 30% using a 10% OME blended diesel as a transportation fuel compared with conventional diesel. [ABSTRACT FROM AUTHOR]

The conversion of biomass for the production of liquid fuels can help reduce the greenhouse gas (GHG) emissions that are predominantly generated by the combustion of fossil fuels. Oxymethylene ethers (OMEs) are a series of liquid fuel additives that can be obtained from syngas, which is produced from the gasification of biomass. The blending of OMEs in conventional diesel fuel can reduce soot formation during combustion in a diesel engine. In this research, a process for the production of OMEs from woody biomass has been simulated. The process consists of several unit operations including biomass gasification, syngas cleanup, methanol production, and conversion of methanol to OMEs. The methodology involved the development of process models, the identification of the key process parameters affecting OME production based on the process model, and the development of an optimal process design for high OME yields. It was found that up to 9.02 tonnes day −1 of OME 3 , OME 4 , and OME 5 (which are suitable as diesel additives) can be produced from 277.3 tonnes day −1 of wet woody biomass. Furthermore, an optimal combination of the parameters, which was generated from the developed model, can greatly enhance OME production and thermodynamic efficiency. This model can further be used in a techno-economic assessment of the whole biomass conversion chain to produce OMEs. The results of this study can be helpful for petroleum-based fuel producers and policy makers in determining the most attractive pathways of converting bio-resources into liquid fuels. [ABSTRACT FROM AUTHOR]

Unmanned Aerial Vehicle (UAV) based remote sensing is one of the modern techniques for crop management, which has been used in this study for biomass and Nitrogen (N) level estimations for Stevia rebaudiana, a medicinal crop used as an alternative to sugar as a natural sweetener. Different levels of nitrogen treatments were given to S. rebaudiana and the crops were harvested for biomass estimation. Mica sense Altum multispectral sensor on board was used for acquiring the image data of the crop. The linear regression model was used to examine the best vegetation index using K-fold cross validation approach. Excess Green Index (ExG) was identified as best vegetation index for biomass estimation (R2 = 0.7; RMSE = 23.77 g/m2; nRMSE = 29.14%), whereas Enhanced Normalized Difference Vegetation Index (ENDVI) was found as best predictor for Nitrogen (N) level estimation (R2 = 0.9; RMSE = 1.75 g/m2; nRMSE = 14.59%). [ABSTRACT FROM AUTHOR]

Minimum production cost and optimum plant size are determined for pellet plants for three types of biomass feedstock – forest residue, agricultural residue, and energy crops. The life cycle cost from harvesting to the delivery of the pellets to the co-firing facility is evaluated. The cost varies from 95 to 105 $ t −1 for regular pellets and 146–156 $ t −1 for steam pretreated pellets. The difference in the cost of producing regular and steam pretreated pellets per unit energy is in the range of 2–3 $ GJ −1 . The economic optimum plant size (i.e., the size at which pellet production cost is minimum) is found to be 190 kt for regular pellet production and 250 kt for steam pretreated pellet. Sensitivity and uncertainty analyses were carried out to identify sensitivity parameters and effects of model error. [ABSTRACT FROM AUTHOR]

D-lactic acid is used as a monomer in the production of poly-D-lactic acid (PDLA), which is used to form heat-resistant stereocomplex poly-lactic acid. To produce cost-effective D-lactic acid by using all sugars derived from biomass efficiently, xylose-assimilating genes encoding xylose isomerase and xylulokinase were cloned into an L-lactate-deficient strain, Lactobacillus plantarum. The resulting recombinant strain, namely L. plantarum NCIMB 8826 ∆ ldhL1-pLEM- xylAB, was able to produce D-lactic acid (at optical purity >99 %) from xylose at a yield of 0.53 g g. Simultaneous utilization of glucose and xylose to produce D-lactic acid was also achieved by this strain, and 47.2 g L of D-lactic acid was produced from 37.5 g L glucose and 19.7 g L xylose. Corn stover and soybean meal extract (SBME) were evaluated as cost-effective medium components for D-lactic acid production. Optimization of medium composition using response surface methodology resulted in 30 % reduction in enzyme loading and 70 % reduction in peptone concentration. In addition, we successfully demonstrated D-lactic acid fermentation from corn stover and SBME in a fed-batch fermentation, which yielded 61.4 g L D-lactic acid with an overall yield of 0.77 g g. All these approaches are geared to attaining high D-lactic acid production from biomass sugars to produce low-cost, highly thermostable biodegradable plastics. [ABSTRACT FROM AUTHOR]

Pipeline hydro-transport is an alternative to truck delivery of agricultural residue (lignocellulosic) biomass. Pipeline hydro-transport benefits from economies of scale, reduces total delivery costs, and enables bio-based energy facilities to achieve higher capacities. In this study, the empirical correlation based on experimentally developed data for pipeline transport of agricultural residue-water mixtures (slurry) was used to develop a data-intensive techno-economic model to estimate the cost of pipeline hydro-transport of wheat straw and corn stover to a bioethanol refinery. The total cost of pipeline hydro-transport was found to be lowest at 8.8% dry matter slurry solid mass content and 2.5 m s−1 slurry velocity. At this biomass slurry solid mass content and velocity, the pipeline hydro-transport of biomass was found to be economically more viable than truck delivery at capacities of 0.45 M dry t yr−1 or more for a one-way pipeline and 1.4 M dry t yr−1 or more for a two-way pipeline (with the return of the carrier liquid). The ability to economically hydro-transport agricultural residue biomass in pipes offers the opportunity to develop large-scale bioethanol plants. © 2015 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

A process model was developed to determine the net energy ratio (NER) for both regular and steam-pretreated pellet production from ligno-cellulosic biomass. NER is a ratio of the net energy output to the total net energy input from non-renewable energy source into the system. Scenarios were developed to measure the effect of temperature and level of steam pretreatment on the NER of both production processes. The NER for the base case at 6 kg h −1 is 1.29 and 5.0 for steam-pretreated and regular pellet production respectively. However, at the large scale NER would improve. The major factor for NER is energy for steam and drying unit. The sensitivity analysis for the model shows that the optimum temperature for steam pretreatment is 200 °C with 50% pretreatment (Steam pretreating 50% feed stock, while the rest is undergoing regular pelletization). Uncertainty result for steam pretreated and regular pellet is 1.35 ± 0.09 and 4.52 ± 0.34 respectively. [ABSTRACT FROM AUTHOR]

Biomass fuels have long been accepted as useful renewable energy sources, especially in mitigating greenhouse gases (GHG), nitrogen oxides, and sulfur oxide emissions. Biomass fuel is carbon neutral and is usually low in both nitrogen and sulfur. For the past decade, various forms of biomass fuels have been co-combusted in existing coal-fired boilers and gas-fired power plants. Biomass is used as a supplemental fuel to substitute for up to 10% of the base fuel in most full commercial operations. There are several successful co-firing projects in many parts of the world, particularly in Europe and North America. However, despite remarkable commercial success in Europe, most of the biomass co-firing in North America is limited to demonstration levels. This review takes a detailed look at several aspects of biomass co-firing with a direct focus on North America. It also explores the benefits, such as the reduction of GHG emissions and its implications. This paper shows the results of our studies of the biomass resources available in North America that can be used in coal-fired boilers, their availability and transportation to the power plant, available co-firing levels and technologies, and various technological and environmental issues associated with biomass co-firing. Finally, the paper proffers solutions to help utility companies explore biomass co-firing as a transitional option towards a completely carbon-free power sector in North America. [ABSTRACT FROM AUTHOR]

Background: Majority of women living in rural areas use biomass fuels for production of domestic energy. Biomass fuels are an enormous source of indoor pollution when burned in closed space with no ventilation. Combustion products have deleterious effect on lung functions. Aim: To Study the effect of biomass smoke on respiratory symptoms and lung functions in rural non-smoking Indian woman. Materials and Methods: A comparative study was conducted among women visiting hospital >18 years of age belonging to rural areas of Bareilly, to study the effect of biomass smoke on respiratory symptoms and lung functions. The study group comprised of 100 subjects who were exposed to biomass smoke and 100 aged matched subjects who were not exposed to biomass served as controls. A standardized respiratory questionnaire was administered to all subjects and pulmonary function tests were evaluated by MIR SPIROLAB 3. Results: The lung functions (FVC, FEV1, FEV1/FVC, PEFR) were significantly lesser in the study group, exposed to biomass fuel than the controls. Conclusion: Women cooking with biomass fuels have increased respiratory symptoms and have marked reduction in lung functions compared with those cooking with gas. [ABSTRACT FROM AUTHOR]

The depletion of fossil fuels as well as the greenhouse gas emissions from fossil fuel use have led to growing interest in biofuel production from biomass. A new technology, thermo-catalytic reforming (TCR), is one of the contributing interests. TCR technology integrates intermediate pyrolysis with a post-reforming stage to convert biomass into a high-quality bio-oil, biochar, and syngas. In this study, experiments were carried out using three Alberta-based biomass feedstocks – hardwood pellets, softwood pellets, and chips – in a 2 kg h−1 laboratory-scale TCR plant. The results show that the composition of the biomass has little effect on product yield and quality. The TCR gases had a higher heating value of 12.5–12.8 MJ kg−1 and a hydrogen content of 13–15 vol %. The produced TCR bio-oil had low water content (~5 wt %) and a heating value of 32–34 MJ kg−1. The high quality of the bio-oil is reflected in the low O/C ratio of 0.15 and TAN of 6–15 mg KOH g−1. The TCR biochar from all three feedstocks had a high heating value and a high carbon content, as well as low O/C and H/C ratios. A parametric study was conducted for the softwood pellets to observe the effect of reformer temperature (500–700 °C) and reactor temperature (400–550 °C). It was observed that at a reformer temperature of 700 °C, the gas yield increases at the expense of a reduction in bio-oil and biochar. The optimum reactor temperature for the TCR of softwood pellets was found to be 500 °C, in terms of both bio-oil quality and yield. • Thermo-catalytic reforming (TCR) technology incorporates intermediate pyrolysis with high temperature reforming. • The TCR bio-oil had low TAN (6–15 mg KOH/g), and high HHV (32–34 MJ kg−1). • The TCR gases had a hydrogen content of 13–15 vol % and HHV of 12–14 MJ kg−1. • Higher reforming temperature led to increase in gases at the expense of bio-oil. [ABSTRACT FROM AUTHOR]

Agricultural residues, although widely available, are an unused source of energy in Bolivia. Although the government of Bolivia plans to increase the share of renewables in the power portfolio, none of the proposed projects includes agricultural residues as a source of electricity. The present study investigated the techno-economics of a biomass-based electricity generation facility, including the optimum facility size and the levelized cost of electricity from agricultural residues in Bolivia. The biomass feedstocks are the residues from harvesting sugarcane, soybean, corn, rice, sorghum, and sunflower. A novel framework was developed to geographically locate biomass collection points (BCPs), sites for collecting/storing biomass on roadsides using a model developed using GIS. The cost components are the costs of harvesting biomass from fields, baling, transportation to BCPs, storage, nutrient replacement, the premium paid to the farmer, and capital cost for the plant. The transportation costs were estimated using a detailed GIS study through the analysis of the actual road network, and the transportation costs were optimized. Regression models were developed to assess the capital costs of the combustion plants. The conversion technologies considered for Bolivia were grate-firing and fluidized bed combustion. A novel integrated framework, named EN ergy from BIO mass T echno E conomic M odel (ENBIOTEM), was developed. Using this model, we estimated the energy cost to be 71.6 $/MWh for an optimal plant capacity of 300 MW. The main barrier against promoting renewables in Bolivia is the fossil fuel subsidy. Although biomass is currently not competitive with fossil fuels in Bolivia, the results provide information to decision makers for future planning. • A data-intensive techno-economic model was developed for estimation of biopower in Bolivia. • GIS was used to estimate the actual transportation cost using road network in Bolivia. • Regression model-based capital cost was integrated with GIS model to estimate biopower cost. • The biopower cost could be an option for providing in long term when natural gas runs out in Bolivia. [ABSTRACT FROM AUTHOR]

In the hydro-transport of biomass feedstock by pipeline to bio-refineries, the rheology of the biomass slurry directly impacts the specifications and, therefore the cost of pipeline components. In this study, the rheological characteristics of untreated fine wood chip slurries across a broad range of slurry temperatures (5–15 °C) and solids concentrations (3–15 wt% dry-matter) were experimentally studied. Slurry samples were pumped in a closed-circuit pipeline facility where slurry flow longitudinal pressure drops were simultaneously measured. The rheological characteristics of the samples were then measured using a rotational viscometer with a vane-in-cup geometry. At low slurry concentrations (˂6 wt% dry-matter), the biomass slurry exhibited Newtonian behaviour; however, non-Newtonian (shear-thinning) behaviour was seen at higher slurry concentrations. In order to approximate the corresponding rheological parameters, different well-known non-Newtonian viscosity models (power-law, Bingham, Casson, and Herschel-Bulkley) were applied to experimental data. In addition, a new approach for approximating the apparent viscosity of biomass slurries using longitudinal pressure drop measurements was introduced and validated. The method has not been previously applied to non-Newtonian biomass slurries under turbulent flow regimes. • Rheological characteristics of untreated wood chip biomass slurries were studied. • Biomass slurry samples were made off a closed-circuit pipeline facility. • Rotational viscometer with vane-in-cup geometry was used over range of temperatures. • Corresponding rheological parameters were approximated using well-known models. • A pressure drop-based method proposed to approximate viscosity of slurry flows. [ABSTRACT FROM AUTHOR]

Bioenergy will play an intimate and critical role in energy supply and carbon mitigation in the future. In recent years, "customizing the development of bioenergy to local conditions" and "prioritizing distributed utilization" have been the two key principles that have been released by the Chinese government to promote the national‐ and provincial‐level development of bioenergy. While many recognize the importance of bioenergy in achieving low‐carbon transition, little is known about the high‐resolution distribution of usable biomass feedstock and technical bioenergy potential in China, which brings about uncertainties and additional challenges for creating localized utilization plans. We propose a new assessment framework that integrates crop growth models, a land suitability assessment, and the geographic information systems to address these knowledge gaps. Distributions of 11 types of usable biomass feedstock and three kinds of technical bioenergy potential are mapped out through specific transformation technologies at 1 km resolution. At the national level, the final technical biogas potential is 1.91 EJ. The technical bioethanol potential (0.04–0.96 EJ) from the energy crop can supply 0.13–3.12 times the bioethanol demand for the consumption of E10 gasoline in 2015. The technical heat potential (1.06 EJ) can meet 20% of the demand for heating in all provinces (5.38 EJ). Most of the 2020 bioenergy goals can be achieved, excluding that for bioethanol, which will need to require more cellulosic ethanol from residues. At the provincial level, Henan and Inner Mongolia have the potential to develop clean heating alternatives via the substitution of agroforestry residues for coal. The results can provide a systematic analysis of the distribution of biomass feedstocks and technical bioenergy potential in China. With economic factors taken into consideration in further research, it can also support national and provincial governments in making bioenergy development plans in an effective and timely manner. [ABSTRACT FROM AUTHOR]

Background: Harnessing the halotolerant characteristics of microalgae provides a viable alternative for sustainable biomass and triacylglyceride (TAG) production. Scenedesmus sp. IITRIND2 is a fast growing fresh water microalga that has the capability to thrive in high saline environments. To understand the microalga's adaptability, we studied its physiological and metabolic flexibility by studying differential protein, metabolite and lipid expression profiles using metabolomics, proteomics, real-time polymerase chain reaction, and lipidomics under high salinity conditions. Results: On exposure to salinity, the microalga rewired its cellular reserves and ultrastructure, restricted the ions channels, and modulated its surface potential along with secretion of extrapolysaccharide to maintain homeostasis and resolve the cellular damage. The algal-omics studies suggested a well-organized salinity-driven metabolic adjustment by the microalga starting from increasing the negatively charged lipids, up regulation of proline and sugars accumulation, followed by direction of carbon and energy flux towards TAG synthesis. Furthermore, the omics studies indicated both de-novo and lipid cycling pathways at work for increasing the overall TAG accumulation inside the microalgal cells. Conclusion: The salt response observed here is unique and is different from the well-known halotolerant microalga; Dunaliella salina, implying diversity in algal response with species. Based on the integrated algal-omics studies, four potential genetic targets belonging to two different metabolic pathways (salt tolerance and lipid production) were identified, which can be further tested in non-halotolerant algal strains. [ABSTRACT FROM AUTHOR]

This study develops life cycle water footprints for the production of fuels and chemicals via thermochemical conversion of algae biomass. This study is based on two methods of feedstock production – ponds and photobioreactors (PBRs) – and four conversion pathways – fast pyrolysis, hydrothermal liquefaction (HTL), conventional gasification, and hydrothermal gasification (HTG). The results show the high fresh water requirement for algae production and the necessity to recycle harvested water or use alternative water sources. To produce 1 kg of algae through ponds, 1564 L of water are required. When PBRs are used, only 372 L water are required; however, the energy requirements for PBRs are about 30 times higher than for ponds. From a final product perspective, the pathway based on the gasification of algae biomass was the thermochemical conversion method that required the highest amount of water per MJ produced (mainly due to its low hydrogen yield), followed by fast pyrolysis and HTL. On the other hand, HTG has the lowest water footprint, mainly because the large amount of electricity generated as part of the process compensates for the electricity used by the system. Performance in all pathways can be improved through recycling channels. [ABSTRACT FROM AUTHOR]

• Agroforestry forms an explicit part of the hill farming systems. • Mostly all the dominant agroforestry systems were prevalent in the study area. • Silvopastoral and agrohortosilviculture have the highest CO 2 mitigation potential. • Along elevation, the highest total carbon stock was recorded in Zone III. The estimation of carbon stock in agroforestry is crucial for curbing the global climate crisis. In this study, biomass production and carbon storage potential of the prevalent agroforestry systems along an altitudinal gradient in the Chamba district of Himachal Pradesh was carried out during 2019–2021. Agroforestry practices were categorized into eight land use systems viz., agrisilviculture, agrihorticulture, agrosilvohorticulture, agrohortisilviculture, hortiagriculture, silvopastoral, pastoralsilviculture and hortipastoral systems and were divided into four altitudinal ranges viz., <1000 m above sea level (m asl; Z-I), 1000–1500 m asl (Z-II), 1500–2500 m asl (Z-III) and > 2500 m asl (Z-IV). Results revealed that biomass production and total carbon storage (vegetation + soil) were significantly affected by the land use type along the altitudinal gradient. Among the different agroforestry systems, maximum aboveground biomass (47.48 Mg ha−1) and belowground biomass (12.20 Mg ha−1) were recorded for agrohortisilviculture. Biomass production was positively correlated with altitudes and increased with an increase in altitudes. Soil carbon density was the maximum (35.77 Mg ha−1) under silvopastoral showing a decreasing trend along the altitudinal gradient. The total carbon storage potential was observed the maximum (59.76 Mg ha−1) under silvopastoral system followed by agrohortisilvicuture > agrosilvohorticulture > agrisilviculture > pastoralsilviculture > hortiagriculture > hortipastoral > agrihorticulture. Along the elevation gradient, total carbon stock ranged from 43.99 to 51.13 Mg ha−1 with the maximum carbon stock corresponding to Z-III and the minimum for Z-IV. This study offers a useful approach for selecting different land use systems and vegetation patterns to maximize thecarbon stocks in a cost-effective manner, which will further help to mitigate global warming issues in other fragile Himalayan catchments. [ABSTRACT FROM AUTHOR]

This study explores the hydrothermal liquefaction (HTL) of wood chips to biocrude followed by upgrading to diluents, which are used to transport bitumen through pipelines. In this study, we considered a 2000 dry t day−1 plant capacity with two scenarios. The first scenario uses hydrogen for upgrading from the on-site hydrogen production plant (i.e., the hydrogen production scenario) and the other relies on procuring hydrogen from an external source (i.e., the hydrogen purchase scenario). We developed a data-intensive process model for HTL and used it to estimate plant capital costs. Project investment costs for the hydrogen production and hydrogen purchase scenarios are 559.67 and 429.13 M $, respectively. The product values (PV) of the diluent from the two scenarios are 0.98 ± 0.03 and 0.79 ± 0.03 $ L−1, respectively, at a 95% confidence interval. The sensitivity analysis shows that diluent yield and internal rate of return (IRR) have the highest impact on the PV of the diluent, followed by capital cost and biomass cost. The optimum plant size at which the cost of production is lowest is 4000 dry t day−1 for PVs of 0.82 $ L−1 and 0.68 $ L−1 for the hydrogen production and purchase scenarios, respectively. This study offers insights into the techno-economic feasibility of producing diluents from HTL. The results of the study could help in the production of diluents for bitumen transportation for the oil sands industry and help reduce the overall greenhouse gas (GHG) footprint of the oil and gas sector. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

Hydrothermal liquefaction is one of the common thermochemical conversion methods adapted to convert high-water content biomass feedstocks to biofuels and many other valuable industrial chemicals. The hydrothermal process is broadly classified into carbonization, liquefaction, and gasification with hydrothermal liquefaction conducted in the intermediate temperature range of 250–374 °C and pressure of 4–25 MPa. Due to the ease of adaptability, there has been considerable research into the process on using various types of biomass feedstocks. Over the years, various solvents and co-solvents have been used as mediums of conversion, to promote easy decomposition of the lignocellulosic components in biomass. The product separation process, to obtain the final products, typically involves multiple extraction and evaporation steps, which greatly depend on the type of extractive solvents and process parameters. In general, the main aim of the hydrothermal process is to produce a primary product, such as bio-oil, biochar, gases, or industrial chemicals, such as adhesives, benzene, toluene, and xylene. All of the secondary products become part of the side streams. The optimum process parameters are obtained to improve the yield and quality of the primary products. A great deal of the process depends on understanding the underlined reaction chemistry during the process. Therefore, this article reviews the major works conducted in the field of hydrothermal liquefaction in order to understand the mechanism of lignocellulosic conversion, describing the concept of a batch and a continuous process with the most recent state-of-art technologies in the field. Further, the article provides detailed insight into the effects of various process parameters, co-solvents, and extraction solvents, and their effects on the products' yield and quality. It also provides information about possible applications of products obtained through liquefaction. Lastly, it addresses gaps in research and provides suggestions for future studies. [ABSTRACT FROM AUTHOR]