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Agricultural crop residues are the lignocellulosic biomass left in the field after harvesting valuable crop parts. These pose a significant concern due to the waste generated annually, burdening management and contributing to pollution. Numerous studies carried out over decades have demonstrated some effective utilization through thermochemical conversion as a potential feedstock, there is not a proper account of their trends. This systematic review addresses a critical gap in the literature by analyzing the sustainable management of crop residues thermochemically, offering insights into research trends, technologies, and future directions for their utilization as biofuel and bioactive value-added-product applications, that has been largely overlooked in previous narrative reviews. Studies for review were searched on web of science, scopus, and google scholar through a carefully developed search syntax and backward snowball methods. Total 343 papers published in past 23 year matched the study inclusion criteria were selected and meaningful outcomes from meticulous analysis of these studies have been extracted. Research publications show exponential growth, primarily focused on laboratory-based experiments. The most studied process was pyrolysis, and the product was biochar. There has been significant progress in process optimization, integration, and product diversification, paving the way for diverse applications. Recent trends indicate a shift from conventional pyrolysis and gasification towards sustainability, circular economy, efficiency enhancements, and novel applications, reflecting a broader commitment to environmental stewardship and resource maximization. Additionally, the challenges linked with recent innovations are discussed, along with recommendations for future research endeavors concerning these systems. [Display omitted] • Systematically reviewed 343 papers on crop residue thermochemical conversion. • Research trends, progress, future prospects and challenges have been discussed. • Optimization, integration, product diversification and applications were major focus. • Exponential research growth, mostly lab-based works on pyrolysis to produce biochar. [ABSTRACT FROM AUTHOR]

Sewage sludge as a byproduct of industrial and municipal wastewaters treatment is produced worldwide at large quantities. This organic waste contains nutrients, pathogens, heavy metals, organic pollutants and other toxic substances. In recent years, the significant increase in the amount of sludge as an important environmental issue, which is considered both a threat and an opportunity, has highlighted the issue of its proper management. In recent decades, various methods have been used to manage and energy recovery from sewage sludge, including pyrolysis, incineration, gasification, anaerobic digestion, aerobic digestion, landfill, composting, lime and microbial fuel cell. Nowadays bioenergy production from sewage sludge attracted the attention of environmentalists due to environmental and economic considerations. In this regard, microbial fuel cells (MFCs) have gained a great importance as an alternative energy conversion method for bioenergy production. This system converts the chemical energy in the organic substance directly into valuable electrical energy by the catalytic reaction of microorganisms. The effectiveness of the system depends on the reactor configuration, operational and environmental parameters. Identifying and optimizing these parameters are important to increase the system efficiency. In this paper, we reviewed and discussed the effects of different parameters on the treatment and electricity generation from waste activated sludge (WAS) using MFC system such as nature of electrode materials, oxygen flow rate, reactor design, substrates and pH. Furthermore, a better understanding of the MFCs performance for bio-fuel generation from WAS, as well as solving concerns associated to the abilities of this technology in real application is aims of this review. [Display omitted] • To power generation and sewage sludge stabilization, simultaneously. • Impact of configurations and operation of MFC on sewage sludge stabilization. • To study the factors influencing the sewage sludge treatment and power generation by MFC. [ABSTRACT FROM AUTHOR]

This systematic review analyses the potential of cocoa residues for energy conversion using anaerobic digestion and evaluates strategies for optimizing methane production yields, retrieving information from papers published on anaerobic digestion of cocoa residues in journals indexed in Scopus, Web of Science, and PubMed databases. The articles were selected according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method. The effects of operational and compositional variables were evaluated by multivariate (PCA) and bivariate (correlation) statistics. A total of twenty-two studies were selected for this systematic review, and five of them were considered for meta-analysis. This search evidenced a lack of studies on the anaerobic digestion of cocoa residues, leading to, for example, high heterogeneity in methane yields between studies (163 to 382 mL CH4 gVS−1). Operational and compositional conditions in the anaerobic digestion were comparable (statistically significant correlations), and anaerobic digestion was considered efficient in the treatment of cocoa residues. In the meta-analysis, optimizing strategies did not significantly affect methane yields. Nonetheless, pretreatment using organic solvents can lead to inhibitory effects on the process. Anaerobic co-digestion can be considered a satisfactory strategy depending on the origin of the co-substrate. In conclusion, this review has worldwide relevance for the waste treatment sector and regarding the search for sustainable energy alternatives. To the best of our knowledge, this study was the first one that used quantitative methods such as multivariate bivariate statistical approaches and meta-analysis to answer questions related to the energy conversion of cocoa residues using anaerobic digestion. • Anaerobic digestion is poorly studied using cocoa residues as biomass. • Cocoa residues are potential biomass for biogas production. • Optimization strategies did not show statistical significance in the meta-analysis. • Co-digestion can increase methane yields. [ABSTRACT FROM AUTHOR]

The adoption of circular economy and life cycle thinking (LCT) tools plays an important role in implementing and evaluating sustainable development strategies of companies. However, until now there is no review paper on the application of these concepts in the biomass supply chain (BSC). This paper aims to review the application of circular economy and LCT in BSC. PRISMA method was used for the review. The analysis was conducted to examine case studies focusing on (1) approaches and practices of applying circularity economy concepts such as circular economy principles, strategies, indicators, business models, (2) application of LCT tools and sustainable concepts. Besides, benefits, limitations, and discussion of applying these concepts and tools were conducted. The review results show that four circular economy principles are applied (reuse, recycle, reduction and recovery), in forms of three strategies: use innovative technologies, improving operational activities and extending the BSC. Regarding LCT, most of the studies focus on environmental assessment, with some extension to economic and social impacts. Most of the exiting literature studied circular economy and LCT separately; therefore, it is recommended that comprehensive, life cycle-based tools should be developed for businesses and decision-makers to thoroughly assess and improve circularity and sustainability of bioenergy. • There are four common circular economy principles used for biomass supply chains. • The most frequent circular economy activities in biomass supply chain are revealed. • Existing studies pay more attention on environmental and economic sustainability. • Circularity indicators are early-developed and not standardized. • There is a need of circularity and sustainability assessment indicators and tool. [ABSTRACT FROM AUTHOR]

This virtual special issue of ENERGY features 35 top-notch selected extended papers, which were showcased at the CORFU 2022 9th International Conference on Sustainable Solid Waste Management (https://corfu2022.uest.gr) in Corfu Island, Greece from June 15th to 18th, 2022. This special issue of Energy focuses on the cutting-edge research on waste-to-energy (WtE) in the circular economy, greenhouse gas reduction, and sustainable waste management systems that generate energy. This editorial paper provides a brief overview of the key methodologies, discoveries, and future horizons within the 35 selected papers. The contributions in this special issue are divided into five categories: 1) biofuels and biopower; 2) municipal waste management; 3) emerging resource utilization techniques; 4) current research of waste-to-energy for circular economy; and 5) advancements in waste-to-energy technologies. [ABSTRACT FROM AUTHOR]

This article analyzed the location and concentration of forest bioelectricity in Brazil, from 2000 to 2019, available from the National Electric Energy Agency (ANEEL) and used the following indicators: Location Quotient (QL), Concentration Index [CR (k)], Herfindahl-Hirschman Index (HHI), Hoover Index (H) and Coefficient of Gini (G). The main results showed that the supply of electricity from Brazilian forest biomass increased from 562.90 MW and 11 thermoelectric plants in 2000 to 3532.61 MW and 115 thermoelectric plants in 2019, providing an average growth of 10.15% yy of the granted installed power and 13.20% p.a. of thermoelectric power plants. The QL inferred a high concentration of energy supply from black liquor (Rio Grande do Sul, Paraná, Espírito Santo, Bahia, Maranhão and Mato Grosso do Sul) and forest residues in several states, mainly in the North region. At the state level, the CR (4), CR (8) and HHI indexes indicated a deconcentration trend. The identification of the location and concentration pattern that the greatest offer was associated with industrial pulp and paper complexes. These results can indicate to investors the impact of electric power generation in the sector and the most relevant location for the installation of new thermoelectric plants. [ABSTRACT FROM AUTHOR]

Biomass sources are geographically scattered, and seasonal changes influence their availability. Variations in location, type, and feedstock quality impose logistical and storage challenges. Such a dispersion and variety of biomass sources, as well as the dispersion of demand points, may undermine the economies of scale and increase the risk of supply shortage. By consolidating biomass preprocessing and distribution activities in bio-hub facilities, they can contribute to the overall resilience of biomass supply chains (BSCs) and ensure a more sustainable and cost-efficient approach to bioenergy production. As such, investigating the advantages and challenges associated with bio-hub implementation can offer invaluable insights on the efficiency and sustainability of BSCs. Despite its critical role, a major part of the literature on BSCs is confined to the decision-making processes related to biomass suppliers and bioconversion facilities. To bridge this research gap, the current study conducts a systematic literature review on bio-hub implementation within BSCs in the period of the last ten years. Shortlisted papers are classified and analyzed meticulously to extract possible improvements from BSC and modeling perspectives. From the BSC viewpoint, one notable gap is the little attention to mid-term and short-term decisions of bio-hub operations such as inventory control, resource management and production planning. Furthermore, the results revealed that environmental and social aspects of bio-hub implementation require considerable attention. From the modeling perspective, findings illustrate the underutilization of integrated approaches to incorporate micro-level and macro-level information in decision-making. In this regard, a number of areas are suggested for further exploration. [ABSTRACT FROM AUTHOR]

With the Danish government's goals of decreasing 70% of CO 2 emissions by 2030 and reaching a fully decarbonised society in the years after, this paper aims to identify the role of sustainable bioenergy in achieving this goal. The methodology and approach presented are relevant for other countries heading in the same direction. The focus is on strategies to further develop the sustainable biomass resources and conversion technologies within energy and transport paired with CCUS (carbon capture utilisation and storage) to coordinate with other sectors and achieve a fully decarbonised society. By using hourly energy system modelling and a Smart Energy Systems approach, it is possible to create a robust multiple technology strategy and keep the sustainable bioenergy levels. The results are presented as principles and guidelines on how to include the use of sustainable biomass in the individual country as an integrated part of global decarbonisation. [Display omitted] • Methodologies and tools for a strategic analysis of bioenergy and CCUS. • Case study of biomass in a fully decarbonised Danish society in the year 2045. • Design criteria for sustainable biomass in a fully decarbonised society. • Guiding principles for countries being part of a global biomass sustainability. • Robust multi-technology strategy for sustainable biomass levels. [ABSTRACT FROM AUTHOR]

This paper explores social acceptance of different wood-based energy applications in the Great Lakes region in the Upper Midwest, USA. Specifically, the paper examines attitudes and perceptions towards residential wood burning, commercial-scale wood boilers for heat, combined heat and power (CHP) facilities, and industrial power generation in Michigan. In 2021, we conducted a state-wide survey (n = 207) and 30 semi-structured interviews with individuals representing different stakeholder perspectives, including regulatory agencies, biomass industry leaders, non-governmental organizations and scientists who have shaped biomass debates, forest products workers, and Michigan residents. Results suggest that the depth of an individual's knowledge about different types of wood energy applications generally led to more positive attitudes, particularly for smaller-scale uses of wood for heat. Despite perceived environmental, economic, and human health risks of using wood for different energy applications, across all stakeholder groups, 70% of respondents perceived environmental benefits, 61% perceived economic benefits, and 57% perceived health benefits. Changing economic and environmental conditions in different parts of the state contributed to people's attitudes toward different forms of wood energy and their perceptions of associated risks and benefits. A key recommendation of this study is that policy-makers and energy developers seek to understand the complex factors that influence social acceptance when planning for the adoption of new types of wood-based bioenergy technologies. • Perceptions of risks and benefits are critical to understanding social acceptance of wood-based bioenergy technologies. • Knowledge about wood-based energy technologies generally led to more favorable attitudes towards wood energy. • Residents who lived within 50 miles of a biomass facility did not necessarily have more knowledge about wood energy. [ABSTRACT FROM AUTHOR]

Woody biomass energy makes up a large share of renewable energy consumption in the EU, and the largest share in countries like Denmark. However, little is known about how the public perceive it. This paper presents the results of a questionnaire-based survey of the public in Denmark focusing on attitudes toward woody biomass for energy. The main findings are that, while more people favor than oppose it, a large proportion are undecided about the use of woody biomass. The survey also revealed a lack of knowledge about this energy source. A Best-Worst Scaling methodology revealed that Danes prioritize environmental sustainability concerns – namely biodiversity loss, the hindering of the development of other renewable energy sources and the climate change mitigation potential of woody biomass – over societal and/or economic ones when it comes to the promotion of woody biomass. Finally, it was found that concern about climate change, belief in the mitigation potential of woody biomass, and being younger explained the formation of positive attitudes toward woody biomass. Policy makers aiming to take public concerns into account in discussions about Denmark's energy future should focus more on minimizing the negative environmental impacts associated with woody biomass rather than on its economic benefits. [Display omitted] [ABSTRACT FROM AUTHOR]

In order to implement bioeconomy strategy and seek climate change mitigation, the enhancement of bioenergy production and consumption is required. Looking at a bottom-up approach in which a society can choose its renewable energy supplier, it is important to analyze what mechanisms contribute to the willingness to use bioenergy. In this paper, the Lithuania case, when the citizenry got a chance to choose an independent energy supplier, was considered. Applying the structural equation modelling the impact of financial, social and informational mechanisms, knowledge about bioeconomy and about the benefit on the environment and the willingness to use bioenergy was evaluated. The results showed that the financial mechanism and knowledge about bioenergy and the benefit on the environment influenced the willingness to use bioenergy the most. Information mechanism also influenced this intention. Meanwhile, social mechanism had no effect both on knowledge level and intention to use bioenergy. Therefore, this study could contribute to the formation of bioeconomy policy and the enhancement of bioenergy usage in the household sector. [ABSTRACT FROM AUTHOR]

The biological transformation of industrial value creation aims to provide solutions with regard to the ecological challenges of our time. Concerning climate change, the most critical transformation area is the energy sector. Alternatives to fossil energy supply as well as the active removal of carbon dioxide (CO 2) from the atmosphere are considered the most important challenges that technology must provide solutions for. A promising approach in this context is the carbon-negative hydrogen production from biogenic sources (HyBECCS). This approach can be implemented on the basis of existing biogas plants. Technology alternatives for retrofitting these plants to HyBECCS facilities are elaborated and their respective strengths, weaknesses, opportunities and threats are derived in this paper. Further, taking the example of Baden-Wuerttemberg in Germany, the ecologic potentials concerning hydrogen (H 2) production and greenhouse gas (GHG) reduction are estimated. The current total H 2 demand of 1.8 TWh/a in this area could be fully covered if 1/7 to 1/4 of existing biogas plants were retrofitted for H 2 production. The substitution of gray H 2 can avoid GHG emissions of 2.2-3.7 million t CO 2 per year. In addition, capture and storage or long-term use of the resulting biogenic CO 2 can enable negative emissions of 2.5-6 million t CO 2 per year. [ABSTRACT FROM AUTHOR]

• Proposed BECCS deployment criteria are based on socio-enviro-economic objectives. • Life cycle emissions and carbon abatement costs are calculated. • Some of the BECCS pathways are less likely to achieve net negative emissions. • Balancing between socioeconomic aspects such as local job creation opportunities, cost, feedstock supply chain disruptions, and emission reduction targets is discussed. Countries are considering different options to achieve net zero emissions including Bioenergy with carbon capture and storage (BECCS), which is the process of capturing and storing CO 2 from processes that use bioenergy to produce heat, electricity, or biofuels. However, this technology faces sustainability concerns and possesses complex value chains of its emissions. Adding further to this complexity, the literature indicates two opposing views with respect to the potential of BECCS in terms of being able (or unable) to achieve negative emissions. Hence, this paper analyzes in detail a wide range of BECCS pathways in terms of their ability to achieve negative emissions along with their associated costs. Out of seven assessed pathways, our analysis shows that corn to ethanol and biomethane production from maize BECCS pathway in the USA, biomethane production from wet manure in Europe, and baling of straw pellets with trans-Atlantic shipment can achieve negative emissions at a cost of 50, 108, 159, and 232 dollars per ton of CO 2 ($/tCO 2) respectively. Other technologies like poplar pellets, forest residue, and agricultural residue with trans-Atlantic shipment are not able to achieve negative emissions. [ABSTRACT FROM AUTHOR]

Sediment microbial fuel cell (SMFC) has been regarded as a promising device for simultaneously bioenergy supply and bioremediation, but the low power density and less research on bioremediation still hinders its practical application. As the carrier of exoelectrogens, anode is closely related to above characteristics of SMFC. Thus, the modification of anode is a reliable way to improve SMFC performance. In this paper, the graphite plate (GP) is modified with polypyrrole/Co 3 O 4 composite (PPy@Co 3 O 4) by electrodeposition to obtain a high capacitive and conductive electrode. SMFC equipped with PPy@Co 3 O 4 -GP shows maximum power density of 247.89 mW/m2, nearly 1.94 times higher than blank control group (127.61 mW/m2). The microflora analysis exhibits that PPy@Co 3 O 4 -GP has great screening ability for electroactive microbes, and forming electroactive functional microflora involved with Sulfurovum and Streptococcus. The results of sediment composition show that PPy@Co 3 O 4 -GP has good bioremediation potential. This work provides an easy and reliable surface modification method for the development of high-performance bioenergy harvesting and bioremediation SMFC anodic materials. • A three-dimensional cross-linked structure PPy@Co 3 O 4 -GP as anode of sediment microbial fuel cell. • PPy@Co 3 O 4 -GP exhibits high capacitance and conductivity. • PPy@Co 3 O 4 -GP can enhance the power generation performance for sediment microbial fuel cell. • PPy and Co 3 O 4 composite modification facilitates the formation and functional differentiation of electroactive communities for bioanode. • PPy@Co 3 O 4 -SMFC demonstrates good bioremediation potential in sediment environment. [ABSTRACT FROM AUTHOR]

This paper explores the viability of utilizing agricultural biomass-based energy potential, employing mathematical, engineering, and economic modeling techniques. Moreover, the potential of a biogas-based co-digestion (CD) system, integrating its techno-economic performance and environmental sustainability in terms of electricity generation, has also been studied. In this investigation, the categorization of 25 different plant species into two groups: arable field crops (AFCs) and horticultural plants (HPs), was performed. Data was collected during the 2021‐–2022 cropping season in Bangladesh from various sources, including literature reviews, governmental, and non-governmental organizations. The findings revealed that the available agricultural biomass residues, totaling 1,02,585.75 KT, have the capacity to generate 1,33,815 million m3/year of biogas. This energy potential corresponds to 291,125.85 TJ/year or 9231.60 MW of electricity, which can fulfill 88% of the national total energy demand. In terms of levelized cost, the proposed approach is more competitive and shows a greater promise compared to other technologies. Furthermore, it demonstrates environmental friendliness by reducing CO 2 emissions by 156 tons at a cost of $7/ton while earning $1092 annually from the potential carbon-credit market. This approach presents a potential solution to address Bangladesh's energy crisis. The payback period of the system ranged from 2.93 to 3.75 years, with and without the inclusion of a slurry, respectively. The recommended methods hold significant promise for meeting national energy demands. A case study was provided as a proof-of-concept (PoC) to validate the approach. This study is the first of its kind, providing valuable insights into the renewable energy potential in Bangladesh. The results will assist policymakers in formulating sustainable energy policies. • Mathematics, engineering, economics and environmental modeling explored renewable energy. • Techno-economics and environmental sustainability validated the proposed methodology. • Bioenergy-based electricity could supply 88% of the national energy demand of Bangladesh. • A case study was provided as a proof-of-concept (PoC) to validate the approach. [ABSTRACT FROM AUTHOR]

Sustainable development and reducing natural and energy resource consumption are the focus of the policies of many institutions. In this context, livestock farming is one of the major anthropogenic sources of GHG and acidifying gas emissions and requires comprehensive analysis to minimise its ecological footprint. For this reason, it is beneficial to analyse the various processes within this production sector to reduce the consumption of resources, particularly water and soil consumption; reduce energy consumption; and try to valorise the biowaste produced, especially manure, byproducts and wastewater. Reusing residual bioresource and organic waste offers the possibility of valorising a discarded product and, at the same time, reducing the consumption of natural resources. For this purpose, biorefinery processes allow bioresources to be transformed into bioproducts or bioenergy. Therefore, this study investigates the application of biorefinery processes to animal-derived waste, aiming to extract valuable resources while curbing resource consumption. This review analysed 293 scientific papers on biorefinery processes published in the last 11 years applied to livestock biomass to extract relevant information to understand the evolution of this topic and formulate hypotheses regarding future research directions. The analysis strongly emphasizes energy production and a growing interest in insect cultivation. In the coming years, one of the most significant challenges will be the successful transfer of technologies and processes from experimental research to the applied industry. To do this, it will be necessary to reduce costs, exploit economies of scale, improve process management, and develop synergies between different industrial sectors to implement smart circular economy systems. Overall, this review aims to clarify the hypothesis driving research in this area and emphasizes the tangible applications of findings within the broader context of sustainable resource management. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper aims at evaluating the best allocation of potential biomethane generation for the decarbonization of the transport system, presenting a case study in Italy. The country has some peculiar features, such as several operating biogas plants, additional potential feedstock for biogas/biomethane generation, a well-developed natural gas network and established relevant natural gas uses in different final sectors, including transport. Based on current estimates for sustainable biomethane potential by 2030, ranging from 2.3 to 7.6 billion cubic meters depending on the scenario, the analysis compares technologies for the generation, distribution and final use of biomethane. The results of the analysis confirm the potential interesting contribution of biomethane in decarbonizing the Italian transport system: a billion cubic meters of biomethane can lead to 2.33–4.37 Mt CO 2 e savings, depending on the feedstock mix and the application. On a national basis, annual climate emission savings in 2030 range from 10.0 to 26.7 Mt CO 2 e , depending on the scenario. Additional 3.1–8.1 Mt CO 2 of emissions can be avoided if the CO 2 captured during the biomethane upgrading can be stored or reused. The proposed methodology could be used to extend the analysis to other countries, and to the European context. • We analyze the climate emissions of biomethane for different supply chains. • We evaluate the effects of feedstock, distribution strategy and electricity mix. • The results confirm the important role of biomethane for transport decarbonization. • We discuss the best allocation in transport segments based on emissions savings. • We compare alternative biomethane scenarios for Italy in 2030. [ABSTRACT FROM AUTHOR]

[Display omitted] • Lifecycle assessment of coal plus wood and paper waste co-firing with CO 2 capture. • Combustion modelling used to predict direct CO 2 and trace emissions. • Increasing co-firing ratio without CO 2 capture decreases CO 2 emissions slightly. • Lower global warming potential due to CO 2 capture drives a lower endpoint score. • Negative emissions achievable at more than 30 % waste co-firing with CO 2 capture. Bio-Energy with Carbon Capture and Storage (BECCS) is an emerging energy conversion technology with the potential to deliver 'negative emissions', a net removal of CO 2 from the atmosphere that may be necessary to achieve the net-zero targets adopted in the Glasgow Climate Pact at COP26. This paper uses Life Cycle Assessment (LCA) to investigate the environmental impacts of co-firing dry waste biomass (wood and paper waste) while implementing CCS technology (i.e., BECCS) in a conventional black coal-fired power plant. The LCA covers CO 2 emissions and trace contaminants, determined via combustion modelling coupled with chemical-equilibrium-based ash-forming element and trace element calculations. As a case study, the context of New South Wales, Australia, is analysed to assesses the viability and discuss policy implications of waste co-firing BECCS as a future energy source for coal-reliant regions. An increase in co-firing ratio is found to decrease emission intensity. At current typical efficiencies, BECCS with a 10 % co-firing ratio can reduce emission intensity from 938 to 181 kgCO 2 /MWh. At 20 % to 25 % co-firing, the emission intensity of BECCS is comparable with other renewable technologies, and negative emissions are achievable above 30 %, although waste availability in NSW is insufficient to achieve these levels. Moreover, BECCS increases environmental impact in all categories except for global warming potential (GWP), land use, and terrestrial acidification. Nonetheless, when aggregating all impacts, the large reduction in GWP drives an endpoint score reduction, indicating that co-fired BECCS may be preferred over sub-critical black (bituminous) coal-fired power without or with CCS, or other higher emission intensity coal-fired power generation. Therefore, policy makers should consider incentivising waste co-firing BECCS as part of future energy policies towards achieving the net-zero targets, weighing its benefits against other environmental impacts, waste availability and competition with recycling initiatives. [ABSTRACT FROM AUTHOR]

Anaerobic digestion (AD) is a viable technique to address food waste (FW) problems by converting FW into sustainable energy. Despite the advantages of the AD process, large-scale AD plants like in Germany and the USA have not been developed in Australia. Therefore, this paper aims to study the technological, economic, and environmental feasibility of sustainable energy production from household FW in Australia. In addition, this paper discusses the different waste to energy (WtE) technologies along with the operational parameters as well as the challenges in developing a biogas plant. The energy and economic potential analysis of the AD process indicates that the processing of 10% FW from Australian states and territories can generate 1.22 GWh to 35.4 GWh electricity which can subsequently earn AUD 0.54 million to AUD 15.7 million revenue per year. The greenhouse gas (GHG) emissions analysis indicates that conversion of the 10% of Australian FW has the potential to lower GHG emissions by 639,852 tonnes per annum. Hence, it can be said that FW plays a vital role as a promising source of sustainable energy and is capable of benefiting the country's economy significantly and reducing GHG emissions. • FW is a potential source of sustainable energy. • AD is a useful waste to energy process for producing clean energy. • Conversion of FW into energy can significantly lower GHG emissions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Microwave pyrolysis of commercial residual lignin was systematically explored. • In-Situ catalytic microwave pyrolysis was employed without extra catalysts. • No extra microwave absorbers were added, indicating a more economic process. • High yield homogenous bio-oil was achieved by process optimization. • High yield and porosity biochar was generated from black liquor lignin. High-value utilization of residual lignin from the commercial bioconversion process is crucial for the more industrially relevant and feasible bioethanol production. Residual lignin generated from pulp and paper industry faces the similar situation. Bio-crude and biochar production via microwave-assisted pyrolysis is an emerging technology among current residual lignin conversion strategies. In this study, microwave-assisted pyrolysis performances based on the commercial bioconversion residual lignin and black liquor lignin (kraft pulping process) were systematically explored with the in-situ catalysis process. The results showed high amount of residual chemicals existing in both lignin samples successfully served as in-situ microwave absorbers and catalysts, which indicated a more economically feasible process. Pyrolysis parameters were further systematically studied with the goal of achieving optimized products distribution and quality. The results showed that with in-situ microwave absorbers and catalysts, the bioconversion residual lignin favored bio-oil production (36% yield) with phenols, hydrocarbons and easters as the predominant components. While the black liquor lignin favored the production of biochar with high yield (57%), larger BET surface area (183 m2/g) and pore volume (0.123 cm3/g). Because of their unique chemical components and in-situ catalysts, both commercial residual lignin samples produced higher yield and better-quality biochar compared to raw softwood sawdust. In addition, the homogenous bio-oil production was also achieved from the microwave-assisted pyrolysis of bioconversion residual lignin by process optimization. [ABSTRACT FROM AUTHOR]

[Display omitted] • Huge production of pineapple waste at farm and processing site. • Production of different biofuels from pineapple wastes. • Variety of organic and phenolic acids from pineapple wastes. • Utilization of pineapple wastes towards circular bio-economy. Agricultural residues play a pivotal role in meeting the growing energy and bulk chemicals demand and food security of society. There is global concern about the utilization of fossil-based fuels and chemicals which create serious environmental problems. Biobased sustainable fuels can afford energy and fuels for future generations. Agro-industrial waste materials can act as the alternative way for generating bioenergy and biochemicals strengthening low carbon economy. Processing of pineapple generates about 60% of the weight of the original pineapple fruit in the form of peel, core, crown end, and pomace that can be converted into bioenergy sources like bioethanol, biobutanol, biohydrogen, and biomethane along with animal feed and vermicompost as described in this paper. This paper also explains about bioconversion process towards the production of various value-added products such as phenolic anti-oxidants, bromelain enzyme, phenolic flavour compounds, organic acids, and animal feed towards bioeconomy. [ABSTRACT FROM AUTHOR]

Bioenergy is a clean and renewable source of energy that can reduce global depency on fossil fuel, and it is a sustainable, economically viable, and socially acceptable. Bioenergy production aligns with several United Nations Sustainable Development Goals (SDGs) directly or indirectly. Bioenergy feedstocks are spatio-temporally distributed and, therefore, design of a green and sustainable Biomass Supply Chain (BSC) is pivotal for effective commercialization of bioenergy. The BSC starts with biomass harvest and includes collection, processing, storage, and transportation as intermediate processes and ends with biomass delivery at the conversion facilities. All these processes are spatially interlinked. Cost-effective bioenergy generation requires an effective and efficient BSC model. The absence of such model is the major cause of failure of bioenergy plants. With this backdrop, this paper reviewed literature related to BSC, and its elements. The elements are then linked with emissions, economy, and socio-cultural aspects to draw a wider picture of bioenergy for sustainable development. The challenges associated with bioenergy are elucidated with in-depth discussion. The analysis shows that green and sustainable BSC can be a major tool to achieve UN SDGs in many ways. On the contrary, present situation of BSC is challenging from multiple perspectives: environmental, socio-cultural, economic, policy, institutional as well as technological challenges. To achieve global deployment of bioenergy with net zero emissions target, use of advanced and emerging tools and techniques like artificial intelligence, machine learning, remote sensing & GIS, Life Cycle Assessment (LCA) and Bioenergy with Carbon Capture and Storage (BECCS) is recommended. [Display omitted] • Biomass Supply Chain (BSC) models and tools are limited in literature. • This review proposed a sustainable and green BSC with net zero emission profile. • Artificial Intelligence, UAV, drone and spatial data can bring new insights to BSC. • Life Cycle and Circular approach is essential for carbon neutral or negative BSC. [ABSTRACT FROM AUTHOR]

The scarcity of fossils and the environmental problems linked with production and application has increased the demand for sustainable alternatives. Microwave-assisted pyrolysis (MAP) of biomass is among the most sustainable and renewable processes for producing bio-oil and value-added products. The laboratory extensively explored this conversion method and has shown satisfactory generating high-quality bio-oils. This paper assesses the alternatives for improving the parameters for optimum bio-oil production while examining the primary parameters influencing MAP yields. As demonstrated by the results, bio-oil yield is significantly affected by parameters that include pyrolysis temperature, microwave power, microwave absorbent type, and catalysis. To a lesser degree, pyrolysis residence time, biomass particle size, purging gas type, and flow rate impact bio-oil yield. In addition, it has been demonstrated that the MAP method is infinitely scalable and has numerous environmental advantages. The assessment finds that the interaction of many elements must be investigated in depth to enhance the bio-oil product. In order to ascertain the techno-economic survivability of scaling up the technique for commercialization, it is necessary to construct an optimized MAP system at the pilot scale. The Response Surface Methodology (RSM) through the Central Composite Design (CCD) method is suggested for optimizing MAP systems since it considers the interplay between the parameters that influence bio-oil productivity. This overview may direct future research on pilot-scale MAP reactor's design, simulation, fabrication, and operation. [Display omitted] • Parameters influencing bio-oil yield in MAP of lignocellulosic biomass are discussed. • The environmental effects of MAP systems are examined. • The RSM using CCD method is suggested for optimizing MAP systems. • It is recommended to scale up optimized MAP systems for bio-oil production. • The techno-economic and environmental assessments of MAP systems are evaluated. [ABSTRACT FROM AUTHOR]

Crop residue-based bioenergy (CRB) is a green replacement for fossil fuels and an effective way of utilizing crop residues. Understanding CRB's GHG reduction effects is critical for predicting its contributions to carbon neutrality. However, many studies have focused on single products or regional assessments, and results remain uncertain and lacking in systematic examination of the diversity in products, feedstock types and their supply. Therefore, this paper systematically investigates the GHG reduction efficiency, driving factors and abatement costs of principal CRB products using a database of 225 cases composed of 71 carbon trading projects and 154 projects analyzed in scientific publications. The results show that bio-power and/or heat (bio-P&H) is highly efficient (689 kg CO 2 e/t dry CR) and economical (269 $/t CO 2 e) in reducing GHG emissions, but liquid biofuels is not encouraged because of its inefficient performance. Plant size and feedstock collection radius significantly affected GHG reductions of bio-P&H and liquid biofuel. Recommended plant sizes and feedstock types for CRB production were identified from environmental and economic perspectives. Overall, these results clarify the patterns and driving factors of GHG reduction efficiency and abatement costs of various CRB products, providing a framework for optimizing CRB development to combat climate change. [Display omitted] • AsSessing GHG reduction patterns of various crop residue-based bioenergy products. • Comprehensive assessment of the environmental and economic performance. • Identifying the impacts of key factors influencing GHG reduction efficiency. • A meta-analysis based on both scientific publications and project datasets. • Bio-power & Heat shows good GHG reduction efficiency with lower abatement cost. [ABSTRACT FROM AUTHOR]

Biomass plays a dual role as an energy source and a solution for climate change mitigation. There are complexities surrounding decentralized electricity generation, and Ghana could not achieve its 10% renewable energy target in 2020. The paper assesses the greenhouse gas mitigation potential and economic impact of electricity from major food crop residues subjected to anaerobic digestion technology in 16 regions and 88 districts in Ghana from 2017 to 2020. Buswell equation was applied to calculate the biogas and methane yield. The environmental impact assessment was expressed as global warming potential, and the economic feasibility was conducted. The results showed that crop residues' annual theoretical and technical potential was 28.92 Mt and 17.24 Mt. The top four residues with the largest share of technical potential were maize (5.41 Mt), yam (3.58 Mt), plantain (3.05 Mt) and cassava (2.39 Mt). Biogas and electricity potentials were 1,912.74 Mm3 and 3,068.34 GWh, which could offset 15.56% of electricity consumption in Ghana. The Ashanti (478.18 GWh), Eastern (430.20 GWh), Bono East (318.29 GWh) and Northern (314 GWh) regions demonstrated the highest electricity potential. Ghana could generate the highest electricity potential of 46.52 GWh in the districts and a minimum potential of 0.89 GWh annually. Power generation potential from anaerobic digestion had a diesel displacement capacity of 923.35 × 10 6 L with a GHG emissions reduction of 2,507.35 kt CO 2 eq. The largest GHG reduction potential was 38.15 kt CO 2 eq at the district level. The findings show that the project is economically viable, with an average net present value of $ 10,105,904 per region and an electricity cost of $ 0.0321/kWh. The study provides critical insights to policymakers and industry developers for decentralized biomass-based electricity generation in Ghana. • A sustainable crop residue assessment is conducted in Ghana. • The total biogas-based electricity is 3,068.34 GWh. • Ashanti region has high electricity (478.18 GWh) than Greater Accra (9.82 GWh). • The total GHG mitigation is estimated as 2507.35 kt CO 2 eq. • The project is economically viable at a cost of $ 0.0321/kWh. [ABSTRACT FROM AUTHOR]

[Display omitted] • Firewood biomass has traditionally been used to generate energy by burning. • Pathways to anaerobic digestion, enzyme hydrolysis and microbial fuel cells were analyzed. • Circular economy preserves the value of its by-products by reducing time. • Anaerobic digestion and microbial fuel cells help to achieve biomass use with sustainability. • Alternative fuels raise the demand for energy throughout the world. In recent years, biofuel or biogas have become the primary source of bio-energy, providing an alternative to conventionally used energy that can meet the growing energy demand for people all over the world while reducing greenhouse gas emissions. Enzyme hydrolysis in bioethanol production is a critical step in obtaining sugars fermented during the final fermentation process. More efficient enzymes are being researched to provide a more cost-effective technique during enzymatic hydrolysis. The exploitation of microbial catabolic biochemical reactions to produce electric energy can be used for complex renewable biomasses and organic wastes in microbial fuel cells. In hydrolysis methods, a variety of diverse enzyme strategies are used to promote efficient bioethanol production from various lignocellulosic biomasses like agricultural wastes, wood feedstocks, and sea algae. This paper investigates the most recent enzyme hydrolysis pathways, microbial fermentation, microbial fuel cells, and anaerobic digestion in the manufacture of bioethanol/bioenergy from lignocellulose biomass. [ABSTRACT FROM AUTHOR]

This paper makes projections of the theoretical and technical potentials of bioenergy supply for 2050. The projections consider changes in available land for bioenergy and food for the global demand and advancements in yield, productivity, expansion of bio-waste recovery, and energy conversion. We present a literature review on projections. We introduced a novel logical and transparent forecasting model. Three future scenarios were established: business as usual (BUS), optimistic trends (OPT), and full adaptation response (FAR). The projection is carried out based on four adjusting factors. An uncertainty analysis was carry-out based on a Monte-Carlo method. Projections of bioenergy production in 2050 were compared with other projections in the literature. The FAR scenario showed that it would be possible to produce twenty-one times the current primary bioenergy supply and to even supply all global primary energy demand in 2050, mostly by energy crops. The assumptions adopted for the BUS and OPT scenarios make their projections more likely. Therefore, the contribution of bioenergy in the global energy matrix is expected to be between 64 and 313 EJ (7.5%–37%) in 2050. There would be a significant change in the composition of the bioenergy supply from today's mostly firewood to energy crops and biowastes. The technical potential for fuel and electric power mostly follow the supply trends for primary bioenergy (theoretical). The potential avoided greenhouse emissions are estimated. The heuristics and the level of transparency of the novel model will allow adjustments and exploration of other scenarios as time passes. • Novel model for projections of the potential of global primary bioenergy supply. • Bioenergy supply potential is shown for 11 different groups of biomass. • Global primary bioenergy supply could increase up to 6 times by 2050 (37% of demand). • Full adaptation response scenario could meet 100% of the global energy demand. • Bioenergy can play a major role in the global energy supply. [Display omitted] [ABSTRACT FROM AUTHOR]

• BECCS assessment of a power system based on biomass gasification (BIG-CC), integrated into a sugarcane plant. • CO 2 capture by the pre-combustion route has less impact on the sale of surplus electricity. • The CO 2 mitigation cost was estimated at 60 €/tCO 2 for pre-combustion and 52 €/tCO 2 for post-combustion. • The feasibility of CO 2 capture is impacted by the scale and cost of electricity generation. • Conventional cogeneration systems (CEST) are suggested for the first BECCS units. In order to make feasible the efforts that would limit the rise of Earth's temperature to no more than 2 °C, profound changes are required in the energy systems. In this sense, BECCS are considered instrumental to attain possible negative emissions. This draws attention to the sugarcane industry in Brazil, where it is possible to produce fuel ethanol at a relative low cost and a large amount of relatively cheap biomass is available. This paper is part of a research that aims to study the combined production of liquid fuels and electricity, using sustainable sources of biomass and maximizing carbon capture. Two cases related to an innovative technology were evaluated and in both the capture is based on amine technology: pre-combustion capture of CO 2 from the fuel gas derived from biomass gasification, and post-combustion capture from gas turbine exhaust gases. Information from the scientific literature was used in modelling the systems, as well as estimating energy penalties and costs associated with capturing, transporting and storing CO 2. The results indicate technical feasibility of both capture options, but difficulties in setting the full integration of the power unit (BIG-CC) with the sugarcane mill and the CCS system, due to the high demand for thermal energy as low-pressure steam. The estimated CO 2 abatement cost is in the range 60–71 €/tCO 2 for pre-combustion capture, and 52–63 €/tCO 2 in the case of post-combustion. Feasibility results are impacted by the scale of CO 2 capture (0.82–1.44 MtCO 2 /year), particularly in the pre-combustion case, and the relatively high cost of electricity generation. [ABSTRACT FROM AUTHOR]

Forest biomass is one of the few non-fossil and non-weather-dependent energy sources available in the Nordic countries. The future role of forest-based bioenergy is, however, unclear as biomass is a limited resource and has many alternative applications. This study analyses how fossil emissions and land-use is affected by forest bioenergy in the North-European heat and power sector, using an energy system model with endogenous capacity investments. The novelty of this paper lies in the detailed description of the substitution factors for different bioenergy levels toward a fully decarbonised energy system. The main results show that forest biomass remains important for heat production in the Nordic countries towards 2050 in a cost-optimal scenario. According to our model results, less use of forest biomass for heating will increase the use of fossil fuel, wind power, and power-to-heat in 2030, while in 2050 also solar PV will be used as a substitute for forest biomass. Implying that less use of forest biomass will increase the land use from wind and solar PV installation and increase and prolong the fossil carbon emission in the Nordic countries. • 1 TWh biomass reduces the emission with 0.10 mill ton of CO 2 in 2030 in North Europe. • The land-use substitution factor in North Europe is 18–47 km2/TWh biomass in 2050. • Forest biomass remains important for heat production towards 2050. • Excluding forest biomass from the energy sector increases emissions and land use. • Less use of biomass implies more use of land for wind installations. [ABSTRACT FROM AUTHOR]

The rising demand for renewable energy around the world has sparked interest in biomass gasification. However, the technology greatly suffers because of tar species produced during the gasification process, which limits direct use of the produced gas. To address this issue, the paper presents a novel piece of work that focuses on the formation and evolution of tar species consisting of benzene, naphthalene, toluene, and phenol. A two-dimensional numerical model for a downdraft biomass gasifier is developed with a total of 20 thermochemical kinetic reactions to investigate the formation of tar species in the gasifier with the effect of residence time. The model's predictions are validated with the experimental and kinetic data and found to be in good agreement. Besides, the model's ability to simulate the producer gas production from a downdraft gasifier is examined. Reaction rates for volatiles decomposition, combustion, and gasification reactions under different working conditions are investigated. Overall, benzene has the highest concentration of the selected tar species, followed by naphthalene, and with relatively modest amounts of phenol and toluene. • A 2D CFD model was built for a 20 kW biomass downdraft gasifier. • Benzene, naphthalene, toluene, and phenol were used as tar representatives. • Detailed reaction kinetics of tar species were studied. • Tar distribution was presented along the gasifier at the steady & unsteady states. • Different reaction rates are presented within volatiles break-up, combustion, and reduction zones. [ABSTRACT FROM AUTHOR]

Circular economy principles can lead to a series of opportunities to tackle climate change, particularly in cities of developing countries where the generation of waste, consumption and demand for energy is growing rapidly. This paper aims to advance the understanding of the expansion of circularity for tackling climate change using biomass for energy at the urban scale. In addition, little is known about how Circular Economy (CE) flows can be quantitatively integrated, what potential trade-offs exist in promoting Circular Economy using biomass, and how governance models can integrate these flows and contribute to a Circular Economy transition in cities. Based on an empirical study of a city in India, where the private sector participation through an innovative Public-Private Partnership (PPP) model enabled the use of urban wastewater in thermal power plants, the study presents the viability of Circular Economy models at the city scale. The feasibility of a further expansion of this circularity by co-firing biomass in local thermal power plants was analyzed, as a potential solution for reducing pollution and carbon emissions in a hard-to-abate sector. The result indicated an average 20.5 MJ kg−1 calorific value for torrefied mixed biomass pellets from crop residues, which, if applied to about 447 kt y−1 surplus biomass available in Nagpur would amount to 9.18 PJ of energy (per year). Overall, local power plants demanded about 19.85 Mt of coal in 2017–18, equivalent to 297.8 PJ in that fiscal year. Thus, the supply of torrefied pellets from peri-urban crop residues can meet between 2 and 3% of the demand from coal-fired power plants, resulting in a 0.3% decrease in the emissions from the power sector in India in 2017–18 (i.e., 922 MtCO 2), benefiting different sectors and levels of government. The analysis provides a framework for understanding the technical and institutional possibilities for strengthening the relationship between circular economy and climate change in the cities of developing countries by connecting flows and systems within and beyond urban centers. Therefore, the expansion of Circular Economy in cities can occur by integrating urban sectors and policy coordination at different levels of governance. Partnerships between local governments, utilities, and civil society for co-managing energy, water, and waste in cities can reduce the financial burden on national governments, including meeting national emission targets. [Display omitted] • Urban circular economy can be advanced using biomass in thermal power plants. • Our model estimates biomass contribution to national decarbonization targets. • Biomass pellets can meet between 2 and 3% of the demand from local coal-fired power plants. • Such replacement accounts for a 0.3% decrease (or 922 MtCO 2) in the emissions from India's power sector. • Results contribute to the design of CE models for cities and regions by including different levels of government and sectors. [ABSTRACT FROM AUTHOR]

The growing world population, rapid industrialization, and intensive agriculture have increased environmental impacts such as wastewater discharge and global warming. These threats coupled the deficiency of fossil fuel and the rise in crude oil prices globally cause serious social, environmental and economic problems. Microalgae strains can withstand the harsh environments of modern industrial and municipal wastes. The shift toward a circular bio-economy that relies on resource diversification has also prompted the reorganization of traditional wastewater treatment (WWT) processes into a low-carbon, integrated biorefinery model that can accommodate multiple waste streams. Therefore, microalgae-based WWT is now a serious competitor to conventional WWT since the major bottlenecks of nutrient assimilation and high microalgae population have been partially mitigated. This review paper aims to collate advances and new knowledge emerged in recent years for microalgae-based WWT and related biofuel technologies. [ABSTRACT FROM AUTHOR]

Sugarcane bagasse (SCB) is an attractive lignocellulose feedstock for biofuel production due to its high organic content and biomass yield, and ease of collection and storage. SCB-based biofuel production through the biochemical route is considered to be an eco-friendly option. However, the sustainability of this green technology is still questionable for some technoeconomic challenges associated with the pretreatment, detoxification, microbial tolerance to inhibitors, and conversion of SCB hydrolysates into biofuels. Researchers have attempted to overcome these issues, particularly by developing cost-effective pretreatment methods and engineered strains capable of tolerating inhibitors and converting SCB-derived components more efficiently. This review aims to present the current status and challenges in the conversion of SCB into biofuels like biohydrogen, biomethane, biomethanol, bioethanol, and biobutanol. The major economic and environmental perspectives are also discussed to assess the economics and eco-friendliness of SCB as the feedstocks for biofuel production. In addition, this paper also highlights existing knowledge gaps that might inspire the readers to fine-tune their research, innovations, and business plan for the development of cost-effective technologies for SCB-based biofuel production. [Display omitted] • SCB as a feedstock for various biofuels has been discussed in this review. • Production of SCB-based biofuels has a high affordability of the raw material. • Pretreatment still remains a key challenge in viable SCB-based biofuel production. • Multi-product biorefinery for maximum use of SCB is of great importance. [ABSTRACT FROM AUTHOR]

This paper studies the technical, economic, and environmental feasibility of a standalone adsorption cooling system thermally driven by biomass combustion and solar thermal energy. The developed cooling package was benchmarked against a baseline vapour compression refrigeration system, driven by grid electricity and the widely investigated adsorption cooling system driven by solar heat. TRNSYS was utilised to imitate the integrated systems, investigate their year-round performance, and optimise their designs by employing the meteorological data for Rwanda and an existing cold room (13 m2 floor area × 2.9 m height) as a case study. The optimisation study for the system revealed that maximum chiller performance (COP = 0.62), minimum biomass daily consumption (36 kg), and desired cold room setting temperature (10 °C) throughout the year can be achieved if the boiler setting temperature, heat storage size, and heating water flow rate are 95.13 °C, 0.01 m3 and 601.25 kg/h. An optimal PV area/battery size combination of 12 modules/16 kWh was obtained from the economic, environmental, and technical viewpoints. [Display omitted] • A standalone bio-driven adsorption cooling system was developed. • A PV solar system was integrated to drive the system's auxiliaries. • The system's variables were optimised to minimise the cost and environmental impact. • The system's technical, economic, and environmental feasibility were analysed. [ABSTRACT FROM AUTHOR]

Energy generation from biomass is a promising alternative to fossil fuels since biomass resources are available in most parts of the world and offer great flexibility through their capacity for use in different forms of energy carriers. However, its cost-competitiveness remains difficult to assess due to the large variability of bioenergy costs, to which the cost of biomass feedstock contributes disproportionately. To address this issue, this paper evaluates the production cost of primary energy production from ligno-cellulosic biomass based on a literature review covering 106 references in academic and grey literature from 45 countries. Our data relate to five types of ligno-cellulosic biomass: managed forest, wood energy crops, grass energy crops, agricultural residues and forest residues. Our results provide insight into the variability of feedstock costs within and between biomass types. We found that the cost of residues from forestry and agriculture is significantly lower than the other biomass types. We did not find any significant difference between the cost of grass energy crops, wood energy crops and managed forest. Biomass grown in Europe is significantly more expensive than in other regions, while biomass grown in Latin America is significantly cheaper. • We review the production costs of ligno-cellulosic biomass in 45 countries. • The collected data covers five types of biomass worldwide. • There is significant variability in production costs within and between biomass types. • Biomass residues from agriculture and forestry have the lowest production cost. • Production costs are highest in Europe and lowest in Latin America. [ABSTRACT FROM AUTHOR]

[Display omitted] • Composition of MSW plays critical role in determining the most effective WtE technique. • Waste-to-energy technologies for MSW management have been narrated. • Biorefinery aspects of municipal solid waste (MSW) are explained in detail. • Bio-electrochemical processes are capable of generating bioenergy from MSW. Increasing municipal solid waste (MSW) generation and environmental concerns have sparked global interest in waste valorization through various waste-to-energy (WtE) to generate renewable energy sources and reduce dependency on fossil-derived fuels and chemicals. These technologies are vital for implementing the envisioned global "bioeconomy" through biorefineries. In light of that, a detailed overview of WtE technologies with their benefits and drawbacks is provided in this paper. Additionally, the biorefinery concept for waste management and sustainable energy generation is discussed. The identification of appropriate WtE technology for energy recovery continues to be a significant challenge. So, in order to effectively apply WtE technologies in the burgeoning bioeconomy, this review provides a comprehensive overview of the existing scenario for sustainable MSW management along with the bottlenecks and perspectives. [ABSTRACT FROM AUTHOR]

Increasing demand for energy and also escalating environmental pollution show that industries cannot rely on fossil fuels, and it is necessary to adopt an alternative. In recent decades, algal bioenergy has emerged as a renewable energy source in different industries. However, algal bioenergy production is costly and faces different challenges (technical and non-technical) and unknown aspects that need to be addressed. Experimental and theoretical research works have revealed that the efficiency of algal bioenergy production is influenced by several factors, including algae species, temperature, light, CO 2 , cultivation method, and available nutrients. Algal bioenergy production on commercial scales in cost-effective ways is the main aim of industries to compete with fossil fuels. Hence, it is vital to obtain a comprehensive knowledge of the previous findings and select a suitable pathway for future studies/activities. In the present review paper, the potential of microalgae bioenergy production, influential parameters, previous experimental and theoretical studies, and different methods for microalgae biofuel production from cultivation stage to utilization are reviewed. Moreover, this work discusses the engineering activities and economic analysis of microalgae cultivation to utilization. Useful suggestions are also made for future research investigations. The outcomes of the present work confirm that innovative engineering methods can overcome scale-up challenges, increase the rate of production, and decrease the cost of algae bioenergy production. Hence, there is no long way to produce cost-effective algae bioenergy on commercial scales. [Display omitted] • Types, properties, and potential of microalgae for bioenergy production and utilization are summarized. • The influential factors in algae bioenergy production processes are highlighted. • The use of wastewater for microalgae production can decrease the total costs. • Possible strategies for increasing microalgae production (e.g., genetic engineering) are addressed. • Challenges in research/engineering activities and possible solutions in algae bioenergy area are listed. [ABSTRACT FROM AUTHOR]

The growing interest in renewable energies requires increased consciousness regarding their impact on the territory and communities. For this reason, several researchers have studied the conditions that influence the balance between the benefits and costs of new bioenergy plants, producing a wide-ranging review of studies regarding the optimal location of plants. This process is based on several economic, social and environmental conditions. One of the most valuable and useful tools to evaluate the criteria and attribute the proper weight is the multicriteria decision model/analysis (MCDM/A). This review summarizes the studies of the last 20 years to describe the criteria that influence the location of bioenergy plants and how the authors compared and categorized the alternatives. In total, 40 papers were reviewed, studying i) the adopted criteria and multicriteria decision model/analysis and ii) the environmental and social conditions that influence this type of analysis. As a result, 55 criteria, divided into 13 subgroups and three main groups (social, economic, and environmental), are identified and studied. This research can support future studies that address the territorial management of energy sources and integrate different types of renewable energies. [ABSTRACT FROM AUTHOR]

The current editorial summarized some of the scientific works presented in the Sustainable Energy and Environmental Protection (SEEP) conference-held at the University of the West of Scotland, UK, 2018. The selected work was directly related to the scope of the Renewable, Sustainable Energy Reviews (RSER) journal. During the conference activities, experts from all around the world in the subjects of: renewable energy, climate change, optimization, and economics presented and discussed the progress made in renewable energy sources, as well as the new strategies for protecting the environment from the hazards connected with fossil fuel utilization. The methods presented in the conference focused on several directions: the development of efficient energy conversion systems with low/no environmental impacts; the suggested policies to widespread renewable energies; the restriction in the emission of greenhouse gases, and the recent progresses in CO 2 capture. This editorial focused on the renewable energy developments and their positive effect on the climate change, and briefly summarized the accepted manuscripts in this issue. • Effects of renewable energy on climate change. • Background on the International Conference on Sustainable Energy and Environmental Protection SEEP. • Summary of selected papers of SEEP 2018. [ABSTRACT FROM AUTHOR]

Indonesia has an intensive agro-industrial sector which evolves large volumes of residues each year. Currently, these residues are under-utilized and have a deleterious impact on the environment, Oil Palm Empty Fruit Bunches (OPEFBs) in particular are highly abundant and offer good potential for conversion to bioenergy and bio-based products, in particular bioethanol and xylitol (widely used as an artificial sweetener and can substitute sugar in food and pharmaceutical industries). This paper provides a comprehensive review of the techno-economic opportunities and challenges for the wider utilization of OPEFBs for the generation of bioethanol and xylitol in Indonesia. This review highlights the significant potential for the valorization of OPEFB based on resource availability in the country (828 MWe/year or 45.86 Mt/year) and growing demand for both bioethanol (from 0.22 billion L in 2019 to 10.38 billion L in 2025) and xylitol (up to 2.20 kt in 2020). Various process configurations were explored to assess the potential for simultaneous co-production of bioethanol and xylitol. A mass balance and techno-economic assessment showed that the preferred scenario was Scenario 3 (co-production of bioethanol with xylitol and lignin) and that this has the potential to generate 46,145 kL bioethanol, 7.716 kt xylitol, and 25.704 kt lignin per year. This is significant given the limited production for both bioethanol and xylitol in the country currently. Further work is required to address challenges around technical, policy and supply chains. This work provides an original and novel strategy to support the wider adoption of commercially viable bioethanol production in Indonesia. • An abundance of oil palm empty fruit bunches (OPEFB) creates prospect for biorefining. • Manufacture and supply of bioethanol and xylitol in Indonesia is feasible. • Multiple scenarios are proposed for mono- and co-production of bioethanol and xylitol. • Co-production of bioethanol and xylitol promotes sustainable bioeconomy. • Challenges remain on scalability, financial incentives and supply chain integration. [ABSTRACT FROM AUTHOR]

[Display omitted] • Classifications and strategies of NZEBs were reviewed. • Multi-criteria analysis supports NZEB designing. • Renewable energy supply options for NZEBs are summarized. • Cost-benefit analysis and life cycle assessment needed for criterion evaluation. Decarbonizing the building sector is extremely important to mitigating climate change as the sector contributes 40% of the overall energy consumption and 36% of the total greenhouse gas emissions in the world. Net-zero energy buildings are one of the promising decarbonization attempts due to their potential of decreasing the use of energy and increasing the total share of renewable energy. To achieve a net-zero energy building, it is necessary to decrease the energy demand by applying efficiency enhancement measures and using renewable energy sources. Net-zero energy buildings can be classified into four models (Net-Zero Site Energy buildings, Net-Zero Emissions buildings, Net-Zero Source Energy buildings, and Net-Zero Cost Energy buildings). A variety of technical, financial, and environmental factors should be considered during the decision-making process of net-zero energy building development, justifying the use of multi-criteria decision analysis methods for the design of net-zero energy buildings. This paper also discussed the contributions of renewable energy generation (hydropower, wind energy, solar, heat pumps, and bioenergy) to the development of net-zero energy buildings and reviewed its role in tackling the decarbonization challenge. Cost-benefit analysis and life cycle assessment of net-zero energy building designs and their challenges were reviewed to shape the priorities of future development. It is important to develop a universal decision instrument for optimum design and operation of net-zero energy buildings. [ABSTRACT FROM AUTHOR]

• Whole-tree harvest has not reduced site productivity on this relatively fertile site. • 35-year site productivity suggests whole-tree harvest is sustainable on this site. • Tree diameter increased after thinning but not biomass productivity. • Nitrogen fertilizer did not increase stand productivity. • Chesuncook catena soils may be able to support a bio-economy in northern Maine. Global trends in the demand for forest products, decreasing total area of actively managed forests, and pressures to increase profit margins suggest that forest management intensity will continue to increase in the future. These trends have typically led to shorter rotation lengths and increased utilization of forest biomass to supply the bio-economy with feedstocks for energy, novel bio-chemicals, traditional pulp and paper, panels and solid forest products. The combined influence of increased utilization and shortened rotation lengths have raised concerns regarding potential soil nutrient depletion and corresponding reductions in site productivity. In response to these concerns, the Weymouth Point Study Area (WPSA) in north-central Maine was established in a spruce-fir forest in 1979 to quantify the effects of whole-tree harvesting (WTH) and stem-only harvesting (SOH) on nutrient cycling and site productivity in adjacent, paired watersheds with large fixed-area plots. From 1979 to 2016, 49 permanent sample plots were established across three soil drainage classes to evaluate tree- and stand-level growth and nutrition response to harvest residue management and silviculture practices. Harvest treatments were implemented in 1981 with SOH simulated by returning delimbing residues after WTH, including chipped tops, branches and foliage (CHP), and lopped-and-scattered residues (LOP). The harvested watershed was aerially treated with triclopyr herbicide in the fourth growing season following WTH to release naturally regenerated conifers from herbaceous and woody weed competition. Response to silviculture practices were evaluated following pre-commercial thinning (PCT) and the addition of ammonium-nitrate fertilizer (FERT) treatments initiated 10 and 12 years following WTH, respectively. Thirty-five years post-harvest, tree growth and nutrient uptake have not been significantly affected by WTH at this location. Mean tree size was positively influenced by PCT; however, FERT did not significantly affect mean tree size. There were also no significant effects of treatments on aboveground biomass production and net nutrient uptake in trees. These results suggest that WTH at final felling for bio-economy feedstock production in spruce-fir forests similar to those at the WPSA (Chesuncook catena soils) is sustainable. However, this hypothesis is based on mid-rotation assessment of tree growth as an indicator of sustainable forest management. Further research is required to confirm the absence of negative impacts on tree- and stand-level growth and nutrition through the end of the current rotation. [ABSTRACT FROM AUTHOR]

Bioenergy has obvious advantages over conventional fossil fuels owing to its renewability and huge capacity, which has dominating role in shielding the energy security that can be a favourable alternative to the disruption of food, resources and the atmosphere. In order to maintain their immediate energy levels and restore the atmosphere, coal-based countries need alternative fuels. For example, wonder inclusion to renewable energy are biofuels derived from crop residues devoid of sacrificing on food production. Annually, about 65 million tonnes (or 280 million metric tonnes) of energy crop-based ethanol are generated, which itself is equal to China's present gasoline ethanol output (2 million tonnes per year). The adverse effects of bioenergy production can vary highly depending on biological sources, land locations and management practices. Replacing fossil fuels with biofuels can significantly reduce these harmful effects arising from various fossil fuels. Identifying crop growing areas, appropriate bioenergy cultivars and appropriate management practices will contribute to the rig environment and biochemical sustainable development. Improved farm management and landscape planning are valuable for ecological services. This paper discusses several biofuels induced patterns of land managements, and generations of biofuel resources practices, cultivation of bioenergy crops environmental implications, and prospective techniques for establishing ecologically friendly biomass energy programmes. [ABSTRACT FROM AUTHOR]

The role of education and communication is crucial to achieving the transition toward a circular economy (CE). Achieving cognitive, attitude and behavioural changes in the consumer and general population is a very complex process which requires mature scientific knowledge created by specialists. The current study aims to evaluate the degree of maturity of research on CE and bioenergy carried out from the areas of education and communication which are published in scientific literature between 2009 and 2019. The object of study have been scarcely approached from epistemological and methodological point of view, which is the novelty value of this study. To achieve the goal a systematic literature review (SLR) has been carried out on 74 peer reviewed scientific articles and conference papers. The records have been subjected to a clustering process (qualitative analysis) and a subsequent univariable (frequencies and vertical percentages) and multivariable quantitative analysis (comparison of column proportions). The studies' theoretical approaches were identified and the levels of formalisation, the predominant objectives and the hypothesis were analysed. In addition, the analysis of the research areas of studies reveals the epistemological process and outcomes of the literature. Several conclusions are drawn such as the scientific literature in this field is limited in scope. Moreover, from an epistemological perspective, descriptive studies are predominant, mainly addressed from the field of engineering, as well as analytical studies, which are mainly undertaken from Social and Legal Sciences. There are two main groups of articles based on their purpose: those which seek to describe, detail or define; and those which are more innovative, which analyse, establish or deconstruct the phenomenon. The results also show that the level of methodological and theoretical formalisation is limited, which indicates that research is in an initial stage. The foregoing results lead authors to conclude that the object of study has a low level of maturity. • Circular Economy and bioenergy literature on Education or Communication is limited. • The level of maturity of the scientific literature in this field is low. • Descriptive studies are predominant in research whose field is engineering. • The degree of theoretical formalisation of analysed studies is low. • Circular Economy and bioenergy research on Education or Communication is needed. [ABSTRACT FROM AUTHOR]

The Canadian province of British Columbia has large forestry resources and therefore provides an informative example of the potential role of bioenergy in mitigating GHG emissions. Even in biomass-rich British Columbia, forestry resources are only sufficient to meet part of the energy demand. This paper compares different energy conversion routes for forestry waste materials: via hydrothermal liquefaction, thermochemical methanol and bioethanol, renewable natural gas, cogeneration of heat and power, heat-only boilers, and power-only generation. The GHG savings, health impacts, minimum selling prices, and GHG abatement costs for each option are estimated by combining life cycle assessment with a discounted cash flow model. The input-based functional unit of 1 oven-dry tonne biomass provides a better basis for comparing possible uses of finite biomass supply than the commonly-used output-based functional unit of 1 GJ bioenergy. Heat-only boiler for district heating gives the highest GHG reduction of 960 kgCO 2 -eq per oven-dry tonne feedstock, while power-only generation delivers minimal GHG benefit in British Columbia. Heat-only boiler and cogeneration offer the lowest GHG abatement costs (<$-20/tCO 2 -eq), due to lower costs and higher energy conversion efficiencies, and are already economically viable, but will not use all the available resources because health impacts generated by biomass combustion limit their deployment, despite life cycle health benefits for avoiding hazardous emissions from slash burning of forestry waste materials. Refined biofuel options are much less cost-effective (>$50/tCO 2 -eq); further technology improvement and policy support are needed to offset the cost disadvantage. • Comparison based on 1 ODT biomass identifies the most efficient way to utilize this scarce resource. • Producing energy from forestry waste materials can reduce emissions of GHGs and other pollutants. • Biomass-fired heat boiler gives maximum GHG mitigation per ODT feedstock. • Biomass-fired heat boiler and cogeneration are the most cost-effective in GHG mitigation. • Liquid biofuel options cause lower local health impacts but at higher GHG abatement costs. [ABSTRACT FROM AUTHOR]

Bioenergy is considered a promising alternative to achieve carbon neutrality and emission reduction. There is a debate over the role of bioenergy in climate change mitigation because of carbon emissions from the production and utilization of biofuels. Recently, studies on emissions of biogenic volatile organic compounds (BVOCs) have substantially increased as they have a significant impact on human health and climate change due to large emissions and high reactivity. A scientometric analysis of 2895 journal papers during 1991 and 2020 related to BVOC emissions from the Web of Science Core Collection was conducted by CiteSpace and Carrot2. Results showed that three main knowledge domains were BVOC emissions and drivers, BVOCs and their oxidation products in biosphere-atmosphere exchange, and soil BVOCs in plant-microbe interactions during the period under study. Generally, the relationships between plant BVOC emissions and environmental variables (e.g., temperature, drought, light solar radiation, humidity, availability of nutrients, carbon dioxide, ozone, etc.) can be investigated by measurement techniques (i.e., chamber) or models (i.e., Model of Emissions of Gases and Aerosols from Nature). Soils could work as both the sink and source of BVOCs through various processes that are affected by soil temperatures, pH, organic matter, and moisture. Anthropogenic activities might affect the emission of BVOCs and promote the formation of BVOC-derived pollutants (e.g., ozone, particles, etc.). Incorporating BVOC emissions and their relationships with pollutants, biomass, and energy into environmental management and decision-making is a promising direction. [Display omitted] • A scientometric analysis was conducted on the research evolution of BVOC emissions. • Ten clusters generated by CiteSpace were logically reclassified into three hotspots. • MEGAN is the most frequently empirical model for BVOC emission assessment. • BVOC-derived pollutants like SOA are likely affected by anthropogenic activities. • Soils in terrestrial ecosystems can act as both the source and sink of BVOCs. [ABSTRACT FROM AUTHOR]

The aim of this paper was to deepen the knowledge of anaerobic co-digestion of lignocellulosic residues and evaluate the role of soluble organic matter during co-digestion. Buckwheat milling residue (buckwheat hull) was co-digested with different organic wastes to evaluate the effect of co-digestion on biomethane yield, process stability, and their relationship with soluble organic matter. Results showed that co-digestion increased the biomethane yields of buckwheat hull and the best result was achieved from the co-digestion with slaughterhouse wastes (+254% of cumulative biomethane production). Kinetic analysis showed that fruit wastes and brewery trub affected positively anaerobic digestion of lignocellulosic residues, enhancing biomethane potential (+84% and +166%, respectively) and reducing lag phase duration. A positive correlation was found between the soluble organic matter and the biomethane yields during co-digestion experiments. Nevertheless, co-digestion with fruit wastes was affected by an excessive acidification in the early stage of AD (pH 5.7) caused by the rapid conversion of sugars into volatile fatty acids (7 g L-1 at day 15). Although all the digestates showed high concentrations of plant nutrients (the average content of total N was 7.8% dry weight), they were also characterized by residual phytotoxicity (germination index was always 0.0%). results. Increasing the amount of easy biodegradable organic matter during lignocellulosic residues treatment should be the main goal when selecting co-digestion substrates. Chemical composition of co-digestion substrates should be carefully considered, with particular regard to soluble organic matter, to ensure the optimal development of anaerobic digestion with lignocellulosic residues. [Display omitted] • Different co-digestion substrates were tested for lignocellulosic residue digestion. • Soluble organic matter concentration and composition play a key role in co-digestion. • Increased soluble organic matter enhanced biomethane yields. • Composition of co-digestion substrates affects process stability. • Agroindustrial wastes are ideal codigestion substrates for lignocellulosic residue. [ABSTRACT FROM AUTHOR]