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Elephant grass (EG), or Pennisetum purpureum, is gaining attention as a robust renewable biomass source for energy production amidst growing global energy demands and the push for alternatives to fossil fuels. This review paper explores the status of EG as a sustainable bioenergy resource, integrating various studies to present a comprehensive analysis of its potential in renewable energy markets. Methods employed include assessing the efficiency and yield of biomass conversion methods such as pretreatment for bioethanol production, biomethane yields, direct combustion, and pyrolysis. The analysis also encompasses a technoeconomic evaluation of the economic viability and scalability of using EG for energy production, along with an examination of its environmental impacts, focusing on its water and carbon footprint. Results demonstrate that EG has considerable potential for sustainable energy practices due to its high biomass production and ecological benefits such as carbon sequestration. Despite challenges in cost competitiveness with traditional energy sources, specific applications like small-scale combined heat and power (CHP) systems and charcoal production show economic promise. Conclusively, EG presents a viable option for biomass energy, potentially playing a pivotal role in the biomass sector as the energy landscape shifts towards more sustainable solutions; although, technological and economic barriers need further addressing.

Wood fuel from the agroforestry sector is one of the main strategies cited by the EU for reducing energetic dependance on foreign markets. Its sustainability, both economic and environmental, can be improved through the optimization of harvesting and chipping operations. This study was focused on the dynamic and energetic balance of the chipping phase carried out by a chipper operated by the power-take-off (PTO) of a medium-power tractor. Both machines were equipped with sensors for real-time monitoring of fuel consumption, PTO torque and speed, trunk diameter and working time during the comminution of 61 poplar trees grown in a medium rotation coppice system. The data analysis was carried out on the entire dataset (about 29,000 records) without considering their belonging to different trees. By means of proper data ordinations, it has been possible to define all the intervals in which the chipping stopped (e.g., between two trees) and to exclude them from the intervals of actual chipping. This has allowed forcomputation of operative and actual working time, as well as of the basic power required to operate the chipper and the power for actual chipping. Subsequently, the parameter values observed during actual chipping were related to the cutting diameters measured at the same instant. Subsequently, the dataset was divided according to seven diameter classes, and, for each class, the descriptive statistical indices of working time, work productivity, CO2 emissions, energy requirement and fuel consumption were calculated. Eventually, the correlation between the variations in trunk diameter and other parameters was verified both on the whole dataset and based on the class average values. The analysis made it possible to identify the conditions of greatest efficiency for the chipper. More generally, the method could help to increase the accuracy of measurements aimed at characterizing the performance of chippers from the point of view of dynamic energy requirements as well as in relation to different wood species.

Significant research endeavors have focused on microbial fuel cell (MFC) systems within wastewater treatment protocols owing to their unique capacity to convert chemical energy from waste into electricity while maintaining minimal nutrient concentrations in the effluent. While prior studies predominantly relied on empirical investigations, there remains a need to explore modeling and simulation approaches. Assessing MFC systems’ performance and power generation based on real wastewater data is pivotal for their practical implementation. To address this, a MATLAB model is developed to elucidate how MFC parameters and constraints influence system performance and enhance wastewater treatment efficiency. Leveraging actual wastewater data from a municipal plant in Guelph, Canada, six sets of MFC models are employed to examine the relationship between power generation and six distinct parameters (inflow velocity, membrane thickness, internal resistance, anode surface area, feed concentration, and hydraulic retention time). Based on these analyses, the final model projects a total power generation of 50,515.16 kW for the entire wastewater treatment plant in a day, capable of supporting approximately 2530 one-person households. Furthermore, the model demonstrates a notably higher chemical oxygen demand (COD) removal rate (75%) compared to the Guelph WWTP. This comprehensive model serves as a valuable tool for future simulations in similar wastewater treatment plants, providing insights for optimizing performance and aiding in practical applications.

Yeast recycling, which is a common practice in sugarcane ethanol plants, could be expanded if it could be successfully implemented in corn-based ethanol production. However, the process of recycling the yeast remaining after fermentation is hampered by contaminating microorganisms that reduce the fermentation efficiency and compete with the yeast for the fermentable sugars. Currently, antibiotics are used to control microbial contamination. This study proposes chlorine dioxide and electron beam irradiation as alternative control methods for completely inactivating contaminants and minimizing their effect on recycled yeast. For that, wort sterilization using electron radiation (20 kGy) and treatment with a chemical biocide, namely chlorine dioxide (125 mg kg−1), were compared with non-treated wort. Five fermentation cycles were performed using fed-batch systems with 300 g L−1 of fermentable sugars. The results obtained in this study showed the inactivation of contaminants under the effect of electron beam irradiation, which led to an increase in the productivity, yield, and efficiency of fermentation by 0.21 g L−1h−1, 2.6%, and 4.7%, respectively. However, ClO2 did not show promising results in reducing contamination or improving fermentative parameters. Thus, electron beam irradiation of contaminated wort may be a suitable alternative to chemical biocides and would allow the use of recycled yeast in corn-based ethanol plants.

The combination of techno-economic process modelling and life cycle assessment is an integrated methodology that addresses quantitative operational data, and evaluates the emissions associated with any process under development. In particular, the valorisation of waste streams within the context of the circular economy could be considered a valid and promising approach, especially regarding techno-economic and environmental indicators. This manuscript aims to evaluate the integral valorisation of apple pomace from the processing industry into bioethanol, and vinasses (a byproduct of the distillation process) into biogas and digestate as biofertiliser. In addition to biogas production, lagooning and composting were considered as strategies for vinasse management. After the conceptual design of the process options was completed, the environmental profile of bioethanol production was estimated across different scenarios. When biogas production was integrated to reduce the biorefinery’s energy demand, the carbon footprint was 1.13 kg CO2eq∙kg−1. This footprint increased to values around four when lagooning and composting were used as vinasse management strategies. Although the economic dimension posed a significant limitation due to high investment costs, the eco-efficiency analysis showed that the scenario of the co-production of bioethanol and biogas is the best alternative. Despite the promising results, further research is needed to explore the recovery of additional co-products to develop a high-potential strategy for apple pomace.

An experiment was conducted to analyse the potential for obtaining biomass for energy purposes and tall wheatgrass (TWG) seeds grown under conditions of varying pre-sowing fertilisation with compost and mineral fertilisation with nitrogen on sandy soils. Field trials were conducted between 2012 and 2015. The study factors were compost from municipal green areas with I-doses of 0, 10 and 20 Mg∙ha−1 added before sowing and nitrogen II-doses of 0, 40, 80 and 120 kg∙ha−1 added each year in the form of ammonium nitrate. During the experiment conducted on sandy soils, a favourable effect of fertilisation on the morphological parameters of above-ground vegetative and generative parts was found. The experiment resulted in high dry matter yields (DMYs) in the range of 9.08–31.38 Mg∙ha−1 and high seed yields (SYs) (635 kg∙ha−1 to as much as 2397 kg∙ha−1), which depended on the applied fertilisation variant. The applied levels of compost fertilisation had a positive effect on the obtained dry matter yields (DMYs) and SY. Analysing the effect of the applied doses of mineral nitrogen fertilisation (40, 80 and 120 kg∙ha−1) on the dry matter yield of TWG under sandy soil conditions, it should be noted that this factor significantly increased the DMY and SY in all years of the study. At the same time, the response of plants to this factor of the study over the years varied and depended on weather conditions. The high energy yield (192.50 GJ∙ha−1–408.93 GJ∙ha−1) closely related to the high DMY indicates the high suitability of TWG as a new grass species under temperate climate conditions grown for biomass energy production and the possibility to harvest seeds when adequately cultivated.

Precise control of operational parameters in anaerobic digestion reactors is crucial to avoid imbalances that could affect biomethane production and alterations in the microbiota. Restoring the methanogenic microbiota after a failure is essential for recovering methane production, yet no published strategies exist for this recovery. In this study, we restored the methanogenic microbiota in an anaerobic SBR reactor that operates with both biofilm and suspended biomass simultaneously, aiming to treat tequila vinasses. Four strategies were evaluated for restoring the methanogenic microbiota: reducing the initial vinasse concentration, increasing the reaction time (RT), adjusting the carbon/nitrogen (C/N) ratio, and progressively increasing the initial vinasse concentration. Among these, adjusting the C/N ratio emerged as a critical parameter for restoring organic matter removal efficiency and reestablishing methanogenic microbiota. The operational conditions under which the methanogenic activity and microbiota were restored were as follows: Operating the A-SBR with an initial vinasse concentration of 60%, an RT of 168 h, a pH of 6.9 ± 0.2, a temperature of 35 ± 2 °C, and a C/N ratio adjusted to 100/1.9 resulted in stable COD removal efficiency of 93 ± 3% over a year and a high percentage of methanogenic microorganisms in both the suspended microbiota (69%) and biofilm (52%). The normalized methane production (0.332 NL CH4/g CODr) approached the theoretical maximum value (0.35 L CH4/g CODr) after restoring the population and methanogenic activity within the reactor.

Torrefaction was applied to enhance the fuel properties of sawdust (SD) and bark wood (BW), biomass wastes from the rubberwood processing industry. Design Expert (DE) software was used in an experimental design to study the effects of affecting factors including torrefaction temperature and time as well as the biomass size towards the desirable properties such as HHV, mass yield, fixed carbon content, and eco-efficiency values. Promising results showed that the HHVs of the torrefied SD (25 MJ/kg) and BW (26 MJ/kg) were significantly increased when compared to preheated SD (17 MJ/kg) and preheated BW (17 MJ/kg) and in a range similar to that of coal (25–35 MJ/kg). The TGA, FTIR, biomass compositions, and O/C ratios suggested that thermochemical reactions played a significant role in the torrefaction at which thermal degradation coupled with possible in situ chemical reactions took place, to some extent. The optimal conditions of the torrefaction were identified at 320 °C and 30 min for SD, and 325 °C and 30 min for BW. The maximum HHVs at the optimal condition were 22, 23, and 20 MJ/kg while the eco-efficiency values were 29.18, 27.89, and 13.72 kJ/kg CO2_eq*THB for torrefied SD, torrefied BW, and coal, respectively. The findings of this study indicate that torrefied rubberwood residues enhanced HHV, eco-efficiency, and less contribution to CO2 emissions compared to fossil fuels.

Beyond the technical challenge of using biomass to achieve net zero, non-technical factors also impact the likelihood of biomass succeeding in displacing fossil fuel use, such as social, environmental, and economic challenges. The political bioeconomy in the United Kingdom (UK) has supported a small but significant role for biomass within the country’s energy mix, with policy determining who benefits, and who will continue to benefit, from its use. The revised UK Biomass Strategy of 2023 signalled how the government perceives biomass looking forward, and the commitment to a cross-sectoral sustainability framework has the potential to support a redistributive policy that creates new winners in the UK biomass sector. Maximising the redistributive effects of policy is hindered by the siloed nature of policymaking around biomass and undermined by a lack of social legitimacy, both of which must be addressed to enable biomass to contribute towards decoupling the UK’s economy from fossil fuels and to ensure a sustainable transition.

High-gravity fermentation, used for ethanol production from sugarcane, corn, and mixed substrates, offers several benefits. Yeast, a rapidly multiplying unicellular microorganism, can be adapted for high sugar and ethanol tolerance on a lab scale. However, different substrates can enhance fermentation efficiency. Our study consisted of two experiments. In the first, we compared simple batch feeding with a fed-batch system for yeast selection in high-gravity fermentation. We ran eight cycles with increasing initial sugar contents (50 to 300 g L−1). No significant differences were observed in the first seven cycles, but in the eighth, the fed-batch system showed lower glycerol and fructose contents and higher cell viability than the simple batch system. In the second experiment, we used the fed-batch system with 300 g L−1 from sugarcane, corn, and mixed wort. The results showed that mixed wort produced higher ethanol contents and greater fermentation efficiency compared to corn and sugarcane as substrates. In conclusion, our findings indicate that the fed-batch system is more suitable for high-gravity fermentation on a lab scale, and the combination of sugarcane juice and corn can enhance fermentation efficiency, paving the way for integrating these substrates in industrial ethanol production.

The cultivation of perennial flowering wild plant species like common tansy (Tanacetum vulgare L.) seems promising for increasing biodiversity friendliness in rather monotonous bioenergy cropping systems in Central Europe, particularly on marginal sites. However, it is still unclear for which types of marginal agricultural land common tansy would be suitable and where; as a result, low-risk indirect land-use change biomass production through common tansy could be considered. Therefore, the aim of this study was to gather initial insights into the suitability of common tansy for sandy sites by means of a 6 L-pot experiment. For this purpose, five replicates of three substrates were prepared: Luvisol topsoil (control) from a field site near the University of Hohenheim, Germany; and admixtures of 50 and 83.4weight(wt)% of sand to the control (M1, and M2), respectively. This resulted in varying sand contents of the substrates of 4.7 (control), 53.3 (M1), and 83.0wt% (M2). In autumn 2021, common tansy seeds were collected from mother plants bearing the breeder’s indentifier ‘Z.8TAV 85/78’. These plants were part of a long-term field trial initiated at Hohenheim in 2014, where common tansy was grown as part of a wild plant mixture. In June 2022, 0.5 g of the seeds were sown in each pot. The pots were placed in outdoor conditions, arranged in a randomized complete block design and watered evenly as required. At harvest in July 2023, significant differences between the substrates in terms of the above- (shoots) and belowground (roots) development of the common tansy seedlings were observed. In M1, common tansy provided notable biomass growth of 56.6% of the control, proving to be potentially suitable for low-input cultivation under sandy soil conditions. However, an even higher share of sand and low nutrient contents in M2 resulted in minor plant development (14.4% of the control). Hence, field trials on sandy soils of about 50wt% of sand in the texture under tailored fertilization and various climatic conditions are recommended.

According to most energy demand forecasts, woody biomass has the potential to become an important source of renewable energy, especially during the transitional period of energy transition. The aim of this article was to estimate the energy potential of the biomass from the forest and the biomass generated by the mechanical processing of wood raw material and also to show the spectrum of possibilities for the potential use of the biomass for energy production in Poland. This research used available statistical and literature data on the species structure of harvested wood and the qualitative and assortment structures of woody biomass. The basic parameters of the raw material were evaluated in accordance with the EU classification of energy wood. This study confirmed the relationship between the energy potential of woody biomass and energy demand in Poland. The correlation coefficient for these variables was r = 0.984. This correlation was reflected in the significant shares of biomass in the production of electricity (more than 9%) or heat (almost 14%). Energy wood resources in Poland are smaller than in other European Union countries, which affects the scale of the potential use of woody biomass for energy purposes. Nevertheless, the use of such a biomass is fully justified from the point of view of possible development.

The aim of this study was to estimate the shoot weight of four selected hazelnut cultivars and to see if the morphological characteristics of the cultivar and the age of the shoots affect their quality when used as fuel. This study shows that the cultivar ‘Olga’ generated the highest amounts of woody biomass (6507 t·ha−1), while ‘Olbrzymi z Halle’ generated the lowest (3843 t·ha−1). ‘Olbrzymi z Halle’ had the highest calorific values (HHVs) (18.08 MJ·t·ha−1 for annual shoots and 18.03 MJ·kg−1 for perennial shoots) and ‘Olga’ had the lowest calorific values (16.64 MJ·kg−1 for annual shoots and 16.39 MJ·kg−1 for perennial shoots). The age of the shoots had a minimal effect on the chemical and energy parameters. Emissions were the highest for ‘Olbrzymi z Halle’ (CO: 57.74 MJ·kg−1 for perennial shoots, CO2: 1414.05 MJ·kg−1) and lowest for ‘Olga’ (CO: 50.57 MJ·kg−1, CO2: 1238.46 MJ·kg−1). The cultivar ‘Olbrzymi z Halle’, which generated the least amount of biomass compared to the other cultivars, stands out for its high energy value due to its low moisture and ash contents and its high carbon and hydrogen contents, making it attractive for the purposes of biofuel production and supporting sustainable agriculture. The practical implications of the research findings include the selection of suitable varieties for biofuel production, the management of biomass moisture content, and the optimisation of combustion techniques to reduce emissions. The potential for using hazelnut shoots as a biofuel highlights the importance of sustainable agriculture and renewable energy production. The results provide valuable information that can support decisions regarding the cultivation and use of hazelnut shoots for biofuel production while minimising negative environmental impacts.

The immense popularity of coffee around the world generates significant amounts of coffee grounds. They are often improperly disposed of, which can have a negative impact on the environment. Due to their chemical composition and physical properties, coffee grounds are an excellent bioenergy material. This paper presents a study of the feasibility of using spent coffee grounds (CG) as an additive to pine sawdust (PS) pellets to improve their energy properties. The tests were carried out on samples of pellets consisting of 100% PS, 100% CG, and mixtures of 95% PS and 5% CG, 85% PS and 15% CG, and 70% PS and 30% CG. Physical and chemical analyses were carried out to determine the suitability of the obtained pellet as a biofuel in accordance with ISO 17225. Combustion tests were also carried out in a laboratory boiler to analyze flue gases and determine CO and NOx emissions in accordance with EN-303-5 for biomass boilers. The amount of emitted volatile organic compounds (VOCs) was also determined. Experimental results show that the addition of CG to PS reduces the durability of the pellets and increases CO and NOx emissions but increases their energy value and reduces the amount of VOC emissions. The requirements of both standards were fulfilled with a mixture of 95% PS and 5% CG. However, test results show that it is possible to add CG to PS in amounts up to 15%, although this will require additional research.

Biomass continues to play a key role as an alternative to fossil fuels. Woody biomass produces lower greenhouse gas emissions than fossil fuels. However, in order to consider biomass as ‘green energy’, a number of factors should be taken into account, including the characterization of the quality of the resource. Therefore, monitoring quality parameters, such as moisture, ash, N content, is essential to assess the sustainability of biomass for energy production. This paper presents the results of laboratory analyses performed on wood chip samples from four Italian regions over a five-year period (2019–2023). In particular, all quality parameters defined by ISO 17225-9 for industrial wood chips were assessed. Data were analyzed using descriptive, parametric, non-parametric statistics, and multivariate analysis. An interest in quality monitoring has been observed, indicated by an increase in the number of samples received from suppliers and an enhancement in the average values of quality parameters. Moreover, an overall decrease in moisture and N content has been observed, while ash content and heating value have undergone non-linear variations. Statistically significant quality differences between samples from different regions may be the result of different practices, such as outdoor or indoor storage, climate differences, different biomass growth conditions.

The by-products of the wine industry represent a global production of 10.5 to 13.1 million tons of wine pomace annually. This study examines the chemical composition and energy potential of wine pomace and distillation stillage, evaluating their suitability for pellet production within ENplus® standards. Proximate analysis, elemental analysis, and calorimetric analysis were conducted on samples of the two by-products collected in a local Distillery in Portugal. The results reveal that wine pomace has a higher volatile matter content (62.695%) than distillation stillage, which, however, has lower ash content (3.762%) and higher fixed carbon (31.813%). Calorimetric analyses show that distillation stillage has a superior low heating value compared to wine pomace, with values exceeding 19 MJ/kg. Both by-products, however, exceed ENplus® limits for ash (≤0.70), nitrogen (≤0.3), and sulfur (≤0.04) content, presenting challenges for use as high-quality fuel pellets. Combining these biomasses with other materials could reduce the pollutant content of the pellet and improve efficiency. This study highlights the need for pre-treatment strategies to lower ash content and enhance combustion. Policy support for sustainable practices is essential to optimize the use of wine pomace and distillation stillage as renewable energy sources.

The Green Deal targets, along with tightening emissions legislation, foster research on alternative propulsion systems. In non-road mobile machinery (NRMM), these efforts largely rally around sustainable fuels while keeping the benefits of energy security (multi-fueling) high. In this context, the blends of Hydrogenated Vegetable Oil (HVO) and Methanol (MEOH) are amongst the most promising yet under-researched alternatives and, as such, need dedicated methods for determining their suitability in engine applications. In this paper, we evaluate the feasibility of Fourier transform infrared (FTIR) analytics for determining the stability of MEOH-HVO mixtures. The research considers temperature effects during storage by conditioning the test samples at −20 °C and +20 °C. The stability of the blends and different co-solvents is analysed after six weeks, and FTIR spectra are used to identify the chemical bonds. From FTIR analysis, blending MEOH20 with 1-dodecanol results in stable homogenous alkyl-ether fuels, while the MEOH20 blend with methyl-butyrate results in ester fuels. There are observable differences in the blend samples according to their storage temperatures. In conclusion, both fuel blend samples formed different fuel types, which are stable and homogenous at room temperature, posing great potential for their applicability in different NRMM types.

Biomass supply chain (BSC) activities have caused social and environmental disruptions, such as climate change, energy security issues, high energy demand, and job opportunities, especially in rural areas. Moreover, different economic problems have arisen globally in recent years (e.g., the high costs of BSC logistics and the inefficiency of generating bioenergy from low-energy-density biomass). As a result, numerous researchers in this field have focused on modeling and optimizing sustainable BSC. To this end, this study aims to develop a multi-objective mathematical model by addressing three sustainability pillars (economic cost, environmental emission, and job creation) and three decision levels (i.e., strategic (location of facilities), tactical (type of transportation and routing), and operational (vehicle planning). A palm oil BSC case study was selected in the context of Malaysia in which two advanced evolutionary algorithms, i.e., non-dominated sorting genetic algorithm II (NSGA-II) and Multiple Objective Particle Swarm Optimization (MOPSO), were implemented. The study results showed that the highest amounts of profit obtained from the proposed supply chain (SC) design were equal to $13,500 million and $7000 million for two selected examples with maximum emissions. A better target value was achieved in the extended example when 40% profit was reduced, and the minimum emissions from production and transportation in the BSC were attained. In addition, the results demonstrate that more Pareto solutions can be obtained using the NSGA-II algorithm. Finally, the technique for order of preference by similarity to the ideal solution (TOPSIS) was adopted to balance the optimum design points obtained from the optimization algorithm solutions through two-objective problems. The results indicated that MOPSO worked more efficiently than NSGA-II, although the NSGA-II algorithm succeeded in generating more Pareto solutions.

In the field of convective drying, several models have been proposed by different research groups, both theoretical and empirical. However, research on theoretical mathematical models has been superficial and needs to be extended. Empirical models present difficulties in their implementation in other research. It is suggested that further research should focus on obtaining models adaptable to different species and environmental conditions. The aim of this work was to analyse the current state of research on the drying process and mass transfer. It is concluded that drying is a mathematically complex process that must be modelled with differentiated equations in two stages: constant drying rate stage and decreasing drying rate stage. The modelling of the constant drying phase can be based on the convective mass transfer equation, although the prediction of the coefficient with analogies to heat transfer has deviations in biomass. Modelling of the variable rate drying phase should focus on the variation of water diffusivity in porous materials or vapour permeability as a function of material moisture and temperature. A database of homogenised equations particularised for each material needs to be generated to predict drying rates and times under predetermined convection conditions. This represents a scientific challenge and suggests that research in drying kinetics still needs development.

A microbial fuel cell (MFC) is a bioelectrochemical system that generates electrical energy using electroactive micro-organisms. These micro-organisms convert chemical energy found in substances like wastewater into electrical energy while simultaneously treating the wastewater. Thus, MFCs serve a dual purpose, generating energy and enhancing wastewater treatment processes. Due to the high construction costs of MFCs, there is an ongoing search for alternative solutions to improve their efficiency and reduce production costs. This study aimed to improvement of MFC operation and minimize MFC costs by using anode material derived from by-products. Therefore, the proton exchange membrane (PEM) was abandoned, and a stainless steel cathode and a carbon anode were used. To improve the cell’s efficiency, a carbon fiber anode supplemented with activated coconut carbon (ACCcfA) was utilized. Micro-organisms were provided with molasses decoction (a by-product of yeast production) to supply the necessary nutrients for optimal functioning. For comparison, an anode made solely of carbon fibers (CFA) and an anode composed of activated carbon grains without carbon fibers (ACCgA) were also tested. The results indicated that the ACCcfA system achieved the highest cell voltage, power density, and COD reduction efficiency (compared to the CFA and ACCgA electrodes). Additionally, the study demonstrated that incorporating activated coconut carbon significantly enhances the performance of the MFC when powered by a by-product of yeast production.

Algal biomass is a prospective feedstock for the eco-sustainable production of many different products with added value, such as meals, feeds, and fuels. The remaining biomass from the algae can be used as raw material and can be transformed into useful secondary products after the important macromolecules have been removed. By optimizing algal biomass hydrolysate utilizing microbial fermentation, several studies demonstrated the generation of bioenergy (bioalcohol, biogas, and biohydrogen) and biochemicals (organic acids and biopolymers). Since the harvest and maintenance of sustainable algal cultivation incur considerable energy and economical prowess, developing products from algae remains a challenge to be countered in commercial applications. This is a typical bottleneck issue when processing algae for fuels or chemicals at the pilot scale. Implementation of integrated algae biorefinery methods can substantially reduce the cost of production and energy consumption. An algae-based green economy can be financially more viable and utilizable, especially for countries with weaker economies. This review’s goal is to examine the implementation of integrated biorefineries for the recovery of bioproducts generated from algae and potential applications. In this context, the life cycle analysis and business elements of a unified algal biorefinery are also addressed.

The growing demand for social and regulatory forest ecosystem services can significantly modify the availability and cost of biomass for energy purposes. This article presents a model for optimizing biomass supply chains using a linear programming framework integrated with a geographic information system (GIS). Based on a given type of biomass resource, its calorific value, price, distance from the power plant, and transportation costs, the model identifies the optimal source of biomass, allowing it to cover the demand for the required total energy value with the lowest possible costs. The case study includes the Połaniec power plant in southeastern Poland and potential sources of forest biomass and agricultural straw within 100 km of the plant. The impact of constraints on the availability and cost of biomass was analyzed in the following scenarios: (1) all forest and agriculture biomass is available, (2) forest area in Natura 2000 network is excluded, and (3) firewood and forests with dominated ecological and social function are excluded. Unit costs of biomass varied depending on biomass availability and energy demands. The lowest unit costs of biomass (3.19 EUR/MJ) were for energy demand at the level of 1 TJ yearly for all kinds of biomass and the highest (4.91 EUR/MJ) for ecological and social constraints and energy demand 4 TJ. As energy demand increased, unit costs increased, and the ability to meet this demand with just one type of biomass decreased. The energy biomass sector can utilize the model to benefit both biomass producers and their final buyers.

The article examines the influence of six varieties of primocane raspberries, Rubus idaeus L., on the growth parameters and energy properties of the biomass. The unique aim of this study was to show the impact of primocane raspberry varieties, grown for a single harvest, on the growth parameters of the bushes and the energy and emission characteristics of the biomass obtained from the pruned canes. To the best of our knowledge, there is no such analysis connected to varieties of raspberries available in the literature. The following primocane raspberries were assessed: Polana, Polesie, Delniwa, Poemat, Polonez, and Poranek. Among the studied raspberry varieties, Polana was characterized by the highest number of side shoots and the greatest sum of the shoot lengths, while the Polonez variety was characterized by the highest average shoot length and shoot thickness. In the tested raspberry varieties, the weight of the shoots per hectare varied significantly, ranging from 6.06 t in the Poranek variety to 9.05 t in the Delniwa variety. It was shown that the raspberry variety had a significant impact on the higher heating value (HHV) and the lower heating value (LHV). The lowest energy value was found in the Delniwa (HHV—17.32 MJ·kg−1; LHV—16.07 MJ·kg−1) and Polana (HHV—17.33 MJ·kg−1, LHV—16.19 MJ·kg−1) varieties, and the significantly highest value was observed in the Poranek variety (HHV—17.63 MJ·kg−1, LHV—16.39 MJ·kg−1). The assessment of the total volume of exhaust gases showed the highest value of this parameter for the Polesie and Delniwa varieties (6.89 m3·kg−1), with the lowest for the Polana variety (6.69 m3·kg−1).

Anaerobic digestion (AD) is a widely applied technology for renewable energy generation using biogas as energy vector. The existing microbial consortium in this technology allows for the use of several types of biomass as substrates. A promising alternative for the production of high-value products (e.g., mixed volatile fatty acids–VFAs, hydrogen) is the use of modified AD. There are several techniques to achieve this objective by modifying the operating conditions of the process. The literature has described the best AD routes for generating renewable energy or high-value products based on specific substrate types and operating conditions. Few studies have reported the integral fraction valorization of the AD process applying the biorefinery concept. This article provides an analysis of the different routes that favor the production of energy carriers and high-value products involving key issues related to operating conditions and substrates. Moreover, AD is addressed through the biorefinery concept. Finally, a case study is presented where renewable energy and mixed VFAs are generated by applying the biorefinery concept in a number of proposed scenarios using organic kitchen food waste (OKFW) as feedstock. The case study involves an experimental and simulation stage. Then, the economic feasibility of the proposed scenarios is evaluated. In conclusion, AD is a promising and economically feasible technology to produce valuable products from several types of waste materials.

The European Union is targeting climate neutrality by 2050, with a focus on enhancing energy efficiency, expanding renewable energy sources, and reducing emissions. Within Italy’s electricity mix, bioenergy sources, namely biogas, solid biomass, and bioliquids, play a crucial territorial role. A comparative analysis was conducted through Life Cycle Assessment (LCA), utilizing national data from the ARCADIA project, to assess the environmental sustainability of the investigated bioenergy chains and identify the most convenient ones. The study revealed that, among the bioenergy sources, solid biomass emerges as the most environmentally friendly option since it does not rely on dedicated crops. Conversely, biogas shows the highest environmental impact, demonstrating less favorable performance across nine out of the sixteen evaluated impact categories. The LCA underscores that the cultivation of dedicated energy crops significantly contributes to environmental burdens associated with electricity generation, affecting both biogas and bioliquids performance. The cultivation process needs water and chemical fertilizers, leading to adverse environmental effects. These findings highlight the importance of prioritizing residual biomass for energy generation over dedicated crops. Utilizing forestry and agro-industrial residues, municipal solid waste, and used cooking oils presents numerous advantages, including environmental preservation, resource conservation and recovery, as well as waste reduction.

One of the United Nations’ 17 Sustainable Development Goals is to “Ensure access to affordable, sustainable, and clean energy for all.” Additionally, the growing concerns about climate change and energy security have heightened the importance of exploring alternative energy sources to replace fossil fuels. The utilisation of agricultural waste for bioenergy production has acquired significant attention due to its potential to mitigate environmental impacts and provide renewable energy sources. However, the major obstacle to producing bioenergy is managing the supply chain while considering economic, environmental, and social factors in an optimal way. This paper presents a comprehensive overview of the literature on the management of agriculture waste supply chains, specifically related to the use of modelling and optimisation techniques for planning. The first section describes different stages of the supply chain and various technologies for converting biomass to bioenergy. This is followed by a synopsis of the literature reviewed based on decision levels, objective functions, modelling methodologies, and optimisation approaches. Finally, the review highlights limitations and gaps in current research and the areas with potential for further exploration.

Reducing the carbon footprint of energy production is one of the most pressing challenges facing humanity today. Lignocellulosic biomass residues from fruit production industries show promise as a viable energy source. This paper presents a study of the Italian context concerning the utilization of orchard lignocellulosic residues for energy production as electricity or bioethanol. The potential of various orchard residues was assessed through chemical and physical analyses, and an equivalent electrical energy of about 6441.62 GWh or an amount of 0.48 Mt/y of bioethanol was obtained based on the average annual dry residue mass availability of about 3.04 Mt/y. These data represent 9.30% of the national electrical energy production from renewable sources, as well as 6.21% of the Italian demand for gasoline in 2022. Electricity generation from these residues has shown its potential as a reliable and sustainable baseload power source, as well as a source of renewable transportation fuel. The studied process could be a valuable reference to expand these concepts on a global scale to achieve a greener and more sustainable energy future.

Energy production from coal combustion is responsible for nearly 40% of global CO2 emissions including SOx and NOx. This study aims to produce solid biomass fuels from oil-palm residues by torrefaction, having a high heating value (HHV) equivalent to fossil coals. The experiments were designed using Design Expert version 13 software to optimize the conditions affecting the fuel characteristics of the torrefied products. The statistical analysis suggested that the optimal conditions to achieve a high HHV and fixed carbon content while retaining the mass yield of biomass mainly depended on the temperature and torrefying time, while the size played a less important role in affecting the properties. The optimal conditions were observed to be at 283 °C (120 min) for EFBs, 301 °C (111 min) for PF, and 285 °C (120 min) for PKSs. The maximum HHV of 5229, 5969, and 5265 kcal/kg were achieved for the torrefied EFBs, PF, and PKSs, respectively. The energy efficiency of torrefied biomass was increased to 1.25–1.35. Ecoefficiency analysis suggested that torrefaction should be carried out at high temperatures with a short torrefying time. This low-cost bio-circular torrefied biomass showed promising fuel characteristics that could be potentially used as an alternative to coals.

The growing demand for agricultural products has increased exponentially, causing their waste to increase and become a problem for society. Searching for sustainable solutions for organic waste management is increasingly urgent. This research focuses on considering the waste of an Andean tuber, such as Olluco, as a fuel source for generating electricity and becoming a potential sustainable energy source for companies dedicated to this area. This research used Olluco waste as fuel in single-chamber microbial fuel cells using carbon and zinc electrodes. An electric current and electric potential of 6.4 ± 0.4 mA and 0.99 ± 0.09 V were generated, operating with an electrical conductivity of 142.3 ± 6.1 mS/cm and a pH of 7.1 ± 0.2. It was possible to obtain a 94% decrease in COD and an internal resistance of 24.9 ± 2.8 Ω. The power density found was 373.8 ± 28.8 mW/cm2 and the current density was 4.96 A/cm2. On day 14, the cells were connected in earnest, achieving a power of 2.92 V and generating enough current to light an LED light bulb, thus demonstrating the potential that Olluco waste has to be used as fuel in microbial fuel cells.

The need to use renewable sources and matrices with energy potential is widely recognized. The development of innovative technologies aimed at the improvement of energy conversion processes and reducing environmental impacts is currently receiving increasing attention from the scientific community and policymakers. The presence of sugars in airborne particle materials is attributed to biomass combustion. For this reason, these compounds are considered markers of biomass burning. The purpose of this work was to evaluate the emissions produced by agroforestry biomass burning (citrus pruning) by simultaneously sampling both stack emissions and atmospheric particulates in the area around a biomass boiler to understand the real contribution of biomass burning to atmospheric pollution. The combustion tests were carried out by comparing the processes with and without particulate abatement system to see how biomass combustion’s contribution to particulate emission can be controlled and reduced. During the tests, the focus was on particulate matter (PM) speciation in terms of sugar marker identification and determination. This study aims to increase knowledge to better understand the contribution of biomass plants to air pollution and differentiate it from the contributions of other sources, such as vehicular traffic or domestic heating.

Renewable energies present an opportunity to enhance energy security, reduce dependence on imports, and lower greenhouse gas emissions. Natural gas, viewed as a transitional fuel from coal to renewables, lacks reliable environmental sustainability and does not contribute to EU energy independence. Recently, biomethane has been gaining attention as an alternative to natural gas. Obtained from purified or “upgraded” biogas, it offers environmental and economic advantages. Several developed technologies, including absorption, adsorption, membrane separation, and cryogenic separation, are commercially available. However, those are energy- and resource-intensive. In this context, this review aims to examine the recent advancements in biogas upgrading, particularly in physical, chemical, and biological pathways. It focuses on CO2 removal and/or conversion to methane, offering an updated overview for future studies. The technologies are classified based on the separation method (by phase addition, by solid agent, by phase creation, and by biological process), and an analysis of each category is conducted. The discussion covers the economic and environmental characteristics, process complexity, and future research prospects in sustainable technologies. This review highlights the potential of biogas upgrading technologies in contributing to sustainable development, increasing energy security, and achieving greenhouse gas reduction goals that are aligned with EU targets.

Based on the analysis conducted on the state of theory and practice, the expediency of assessing the relationships between the functional indicators of bioenergy production systems using the organic waste of residential areas is substantiated in the projects of the European Green Deal. It is based on the use of existing results published in scientific works, as well as on the use of methods of system analysis and mathematical modeling. The proposed approach avoids limitations associated with the one-sidedness of sources or subjectivity of data and also ensures complete consideration of various factors affecting the functional indicators of the bioenergy production system from the organic waste of residential areas. Four types of organic waste generated within the territory of residential areas are considered. In our work, we used passive experimental methods to collect data on the functional characteristics of bioenergy production systems, mathematical statistics methods to process and interpret trends in the functional characteristics of bioenergy production systems using municipal organic waste, and mathematical modeling methods to develop mathematical models that reflect the patterns of change in the functional characteristics of bioenergy production systems. The results indicate the presence of dependencies with close correlations. The resulting dependencies can be used to optimize processes and increase the efficiency of bioenergy production. It was found that: (1) yard waste has the highest volume of the total volume of solid organic substances but has a low yield of biogas and low share of methane production; (2) food waste has the highest yield of biogas and, accordingly, the highest share of methane production; (3) mixed organic waste has the lowest volume of the total volume of solid organic substances and the lowest content of volatile organic substances. The amount of electricity and thermal energy production varies by type of organic waste, with mixed organic waste having a higher average amount of electricity production compared to other types of waste. It was established that the production volume of the solid fraction (biofertilizer) is also different for different types of organic waste. Less solid fraction is produced from food waste than from yard waste. The obtained research results are of practical importance for the development of sustainable bioenergy production from organic waste in residential areas during the implementation of the European Green Deal projects. They provide further research on the development of effective models for determining the rational configuration of bioenergy production systems using organic waste for given characteristics of residential areas.

In México, the utilization of fast-growing plant species for biomass production presents transportation-related issues such as freshness reduction, the transportation of large volumes with minimal weight due to low density, limited storage availability, and logistical challenges. To enhance understanding in this field, the research aimed to evaluate the densification potential of a variety of organic materials, with a specific emphasis on the biomass derived from eight species of rapidly growing plants, three animal species’ manure, and concentrated feed. After conditioning, 100 g samples underwent particle size analysis and were categorized into seven sizes. Pellets and briquettes (40 g, 10% moisture, 15 MPa pressure, 5 min processing, 80 °C temperature) were produced and evaluated for bulk density (BD) and pellet (PD) and briquette durability (BDU). The predominant particle sizes were 0.850 mm and 0.425 mm. Original biomass bulk density (OBBD) varied notably, with ovine manure (0.50 g cm−3) and cattle feed (0.49 g cm−3) exhibiting the highest values. Caprine manure (0.83 g cm−3) and ovine manure (0.78 g cm−3) yielded the densest pellets at 1.76 and 1.84 g cm−3, respectively. Apple tree pellets achieved premium quality with the highest hardness (97.9%). Cattle manure (1.25 g cm−3) and cattle feed (1.25 g cm−3) had the densest briquettes, with notable BBD/OBBD ratios in pine sawdust (4.6) and corn (4.5). Caprine manure and Acacia biomass briquettes showed premium quality with the highest hardness (99.1%), emphasizing densification variations and the need for tailored approaches based on organic material characteristics.

The long-term performance of perennial energy crops and their elimination is important for long-term planning and use of agricultural land. In this study, the elimination of a six-year-old Sida hermaphrodita (hereafter referred to as Sida) stock for agricultural reclamation was investigated over three years. Crop rotation using maize, winter wheat, and sugar beet, a catch crop, as well as mechanical–chemical treatments were employed according to agricultural practices. After soil grubbing at the beginning of the experiment and prior to further treatments, on half of the former Sida planting area, visible Sida roots were manually removed in addition to determining their potential effect on total resprouting. Prior to each crop harvest, resprouted Sida plants were counted. At harvest, by the end of the first year, 476 versus 390 resprouted Sida plants were found in the investigated areas of 315 m2 each, where preceding manual root removal either took place or not, respectively. This accounted for 76% and 62% of the initial Sida planted. In the second year, the overall number of resprouted Sida declined significantly, accounting for 15 and 11 plants (i.e., 2.4% and 1.8% of initially planted), and in the third year, only two and four residual plants (i.e., 0.3% and 0.6%) were found, representing an almost 100% Sida elimination rate. We conclude that additional root removal did not result in a significant difference in Sida regrowth compared to the mechanical–chemical treatments only. No impediments to harvesting and no loss of yield in any crops were observed due to resprouted Sida in the existing field crops. No Sida plants were found outside the initial field, indicating a low dispersion potential and invasiveness. The results show that successful recultivation of an established Sida stock is possible through common agricultural practices and that resprouting Sida plants did not negatively affect the subsequent crops.

Using waste biomass is considered one of the ways to reduce climate change. Arboreal waste biomass from pine, eucalyptus, and particularly invasive plants (Acacias) would make it possible to transform this natural resource, but needs to be adjusted to current and innovative technologies. The production of high fixed carbon biochar with this biomass would improve not only environmental aspects, but also the use of currently not susceptible materials for other types of exploitation. The objective of this study is to develop biochar from three different waste biomass materials and compare their parameters with those of the original biomass. Thermochemical conversion processes were used in a simple double chamber reactor developed for this study. Temperatures between 400 and 500 °C during 280 min were achieved and allowed to transform the initial biomass in a biochar with a high content of fixed carbon. By comparing the original biomass with the final biochar through tests of humidity, density, calorific values, fixed carbon, and cationic and elemental analysis, an increase in the parameters was confirmed. Fixed carbon of 70%, 77%, and 71% with pine, acacia, and eucalyptus biomass have been obtained, respectively, with yields between 30% and 40%. The results are favorable, particularly with acacia invasive plants, and could help in their difficult silviculture management.

Forest biomass is expected to remain a key part of the national energy portfolio mix, yet residual forest biomass is currently underused. This study aimed to estimate the potential availability of waste woody biomass in the Aizu region and its energy potential for local bioelectricity generation as a sustainable strategy. The results showed that the available quantity of forest residual biomass for energy production was 191,065 tons, with an average of 1.385 t/ha in 2018, of which 72% (146,976 tons) was from logging residue for commercial purposes, and 28% (44,089 tons) was from thinning operations for forest management purposes. Forests within the biomass–collection radius of a local woody power plant can provide 45,925 tons of residual biomass, supplying bioelectricity at 1.6 times the plant’s capacity, which could avoid the amount of 65,246 tons of CO2 emission per year by replacing coal-fired power generation. The results highlight the bioelectricity potential and carbon-neutral capacity of residual biomass. This encourages government initiatives or policy inclinations to sustainably boost the production of bioenergy derived from residual biomass.

This study delves into the intricate landscape of biomass utilization within the food and energy markets. It entails a systematic review of the existing literature with the aim of unraveling the complexities of the food and energy discourse, especially in the context of significant market factors influencing biomass use for food and energy. We leveraged the Scopus database to examine 73 pertinent scientific articles carefully selected following the PRISMA framework. The articles were analyzed using the advanced qualitative data analytics tool NVivo 12 Plus. Furthermore, we employed the Biblioshiny R-package tool to extract valuable insights from the metadata, unveiling pivotal trends and providing descriptive statistical details. The findings offer comprehensive insights into the debate on biomass utilization from 2010 to 2023, tracing the influence of the COVID-19 pandemic. We identify regions that have made notable contributions and highlight those that require increased attention. The analysis underscores the collaborative nature of this field, with 281 authors contributing to 39 different sources. Surprisingly, the observed annual growth rate of −10.93% indicates a potential decline in research output in this field. Nevertheless, the sources identified in our research provide a valuable roadmap for further research exploration of the biomass–food–energy nexus.

Australia has abundant volumes of forest residues that are a potential feedstock for supplying biomass as a renewable carbon carrier to the market. However, there remains an underutilization of this resource, even in mature bioeconomy markets. Several existing or perceived barriers can be attributed to the underdeveloped, forest-based bioeconomy in Australia. One of these is the limited understanding of feedstock supply costs. In this study, two ranking approaches were applied to identify the optimal biomass feedstock supply chain from field to conversion plant gate. A panel of experts embedded in the Australian bioeconomy were employed to first assign ranks to biomass supply chain items by cost intensity. Then, a layer of analytic hierarchical process (AHP) was used to weigh and rank various biomass supply pathways by efficiency. The results reveal that biomass extraction ranks the highest and biomass feedstock storage ranks the lowest, relative to other supply chain costs. Extracting and chipping material in the field attracted the most support from the experts in terms of efficiency, followed by transporting and chipping at the roadside and, finally, transporting and chipping at the conversion plant. This study provides insights for designers of the forest-based bioeconomy in Australia into relative cost drivers that may be applied to investment and industry decisions. It also provides a framework to support further investigations into forest biomass development and the management of biomass as a renewable carbon carrier at a time when Australia is transitioning from an energy policy focused on fossil fuels to a renewable energy strategy.

For all of human history except the past two centuries or so, bioenergy provided nearly all the world’s primary energy. Then, fossil fuels largely replaced bioenergy, but concern about climate change and fossil fuel depletion will force a move back to renewable energy, including bioenergy. The main method used here to study the future of global bioenergy was a literature surview of relevant published papers, with emphasis both on those published after 2020, and those having a global focus. The key finding is that bioenergy is unlikely to greatly increase its share of global energy consumption, for several reasons. Liquid biofuel production for transport is likely to almost disappear as countries progressively phase out internal combustion engine vehicles. Traditional firewood use is also projected to fall. There are also doubts about the technical potential of bioenergy, not only because it must compete with the other uses for biomass—food, fodder, fibre and timber—but also because in many cases its climate change mitigation impact is less than for other approaches, including alternative renewable energy sources. The overall conclusion is that bioenergy will have a minor but still useful role in the future global energy system, but global energy reductions are likely to be more important for climate stability than bioenergy.

High-yield potential perennial crops, such as Miscanthus spp. and Arundo donax are amongst the most promising sources of sustainable biomass for bioproducts and bioenergy. Although several studies assessed the agronomic performance of these species on diverse marginal lands, research to date on drought and zinc (Zn) resistance is scarce. Thus, the objective of this study was to investigate the drought and Zn stress tolerance of seven novel Miscanthus hybrids and seven Arundo clones originating from different parts of Italy. We subjected both species to severe drought (less than 30%), and Zn stress (400 mg/kg−1 of ZnSO4) separately, after one month of growth. All plants were harvested after 28 days of stress, and the relative drought and Zn stress tolerance were determined by using a set of morpho-physio-biochemical and biomass attributes in relation to stress tolerance indices (STI). Principal component analysis (PCA), hierarchical clustering analysis (HCA) and stress tolerance indices (STI) were performed for each morpho-physio-biochemical and biomass parameters and showed significant relative differences among the seven genotypes of both crops. Heatmaps of these indices showed how the different genotypes clustered into four groups. Considering PCA ranking value, Miscanthus hybrid GRC10 (8.11) and Arundo clone PC1 (11.34) had the highest-ranking value under both stresses indicating these hybrids and clones are the most tolerant to drought and Zn stress. In contrast, hybrid GRC3 (−3.33 lowest ranking value) and clone CT2 (−5.84) were found to be the most sensitive to both drought and Zn stress.

Energy production from biomass represents a strategic solution for the achievement of global sustainability goals. In addition, the use of biofuels offers both significant environmental advantages and several socio-economic benefits. In this study, the environmental life cycle impacts associated with the use of woodchips from forest residues for combined heat and power generation in Italy were analyzed. Moreover, the use of woodchips was compared to the use of conventional fossil fuels in similar applications, and different biomass supply scenarios were evaluated to understand their effect on the overall impact related to 1 kWh of electricity. The impacts on “Climate Change” (2.94 × 10−2 kgCO2eq/kWh) and “Resources” (4.28 × 10−1 MJ primary) were revealed to be minimal compared to fossil fuels (reduction of about 95–97%) and forest woodchips emerged as a sustainable alternative for electricity generation. Moreover, impacts regarding “Human health” (3.04 × 10−7 DALY) and “Ecosystem quality” (3.58 × 10−1 PDF·m2·yr) were revealed to be relevant and identified as a research area to be further explored. The findings of this study also highlighted the key role played by the supply mode/distance of the woodchips on the overall life cycle impacts, with the use of “local” biomass representing the best reduction option. Lastly, another aspect to be further investigated is the optimization of the biomass supply.

As living standards improve worldwide, the demand for energy increases. However, climate changes and decreasing fossil fuel deposits have increased interest in renewable energy sources, including pellets produced from forest residues. This study aimed to compare changes in concentration of gases (CO, CO2, O2, volatile organic compounds—VOCs) in enclosed headspaces above pellets produced from deciduous (oak OA, birch BI) and coniferous (pine PI, spruce SP) dendromass and selected types of commercial pellets during their storage. The experiment measured the concentration of gas released from the pellets in storage daily for 14 days. The highest mean CO concentration was found for PI pellets (1194 ppm), and the lowest was for OA (63.3 ppm). Likewise, the highest CO2 concentration was noted for PI pellets (4650 ppm), and the lowest was for BI (1279 ppm). The largest VOC amount was released in the headspace above PI (88.8 ppm), and the smallest was above BI (4.6 ppm). The oxygen concentration was the lowest as measured for PI (minimum 16.1% v/v) and for SP (19.3% v/v). The threshold limit value (8 h) for CO was exceeded for all the pellets under analysis and, in the case of CO2, only for PI after day 10 of incubation. The study findings are extremely important from a scientific (but mainly from a practical) perspective because of the safety of storing and transporting wood pellets. The knowledge of autooxidation processes in those biofuels can help organize their logistics and storage and result in proper warehouse ventilation and monitoring of noxious gases.

Society heavily relies on fossil fuels for energy generation, which poses risks like geopolitical conflicts, environmental degradation, and climate change. Opting for renewable energy sources, such as bioenergy from microorganisms, presents a potential solution to these challenges. Harnessing the energy-producing capabilities of microorganisms enables large-scale renewable energy production, without harming the environment or human activities. Thus, the primary objective of this study was to develop a decision-making method for microbial energy generation, using Mamdani-type fuzzy logic to handle the inherent uncertainties and inaccuracies in this field. A four-level indication structure was created, employing triangular and trapezoidal functions at its endpoints. For fuzzy rule development, five input fuzzy sets and five output fuzzy sets were used when two indicators were involved in the fuzzy machinery, while three input fuzzy sets and five output fuzzy sets were used when three or more indicators were part of the fuzzy machinery. Five scenarios were developed, ranging from 0 to 10 on the following scale: High Criticality (10–8), Tolerable (8–6), Adequate (6–4), Desirable (4–1.5), and Low Criticality (1.5–0). This model is expected to optimize decision-making processes and promote renewable energy alternatives, potentially reducing the dependence on fossil fuels in the future.

Finding sustainable solutions to the increasing waste generation in Ghana has received a lot of attention in recent years. Through several waste-to-energy processes, the energy potential of municipal solid waste has recently witnessed significant technological advancements. The Renewable Energy Master Plan has projected the production of about 122 MWp from waste-to-energy installations by 2030 in Ghana. To help policymakers and engineers achieve national goals, this paper reviews the waste generation in Ghana estimated from 2010 to 2030 and the status of various bioenergy technologies in Ghana. This paper further estimates the energy recovery potential of municipal solid waste in Ghana under incineration, anaerobic digestion, and landfill gas recovery technologies. The review establishes that, by 2030, municipal solid waste generation will increase by 123% of the 2023 quantities and may produce 1484.25 MW of installed electricity capacity and 13,002.03 GWh per year, which would amount to nearly 59% of Ghana’s 2030 renewable energy target. Additionally, it was determined that anaerobic digestion, incineration, and landfill gas recovery technologies, when properly developed, will add 105.33 MW, 301.4 MW, and 377.31 MW of installed electrical capacity, respectively, to Ghana’s energy mix in 2028.

The over-exploitation of fossil fuels and their negative environmental impacts have attracted the attention of researchers worldwide, and efforts have been made to propose alternatives for the production of sustainable and clean energy. One proposed alternative is the implementation of bioelectrochemical systems (BESs), such as microbial fuel cells (MFCs), which are sustainable and environmentally friendly. MFCs are devices that use bacterial activity to break down organic matter while generating sustainable electricity. Furthermore, MFCs can produce bioelectricity from various substrates, including domestic wastewater (DWW), municipal wastewater (MWW), and potato and fruit wastes, reducing environmental contamination and decreasing energy consumption and treatment costs. This review focuses on recent advancements regarding the design, configuration, and operation mode of MFCs, as well as their capacity to produce bioelectricity (e.g., 2203 mW/m2) and fuels (i.e., H2: 438.7 mg/L and CH4: 358.7 mg/L). Furthermore, this review highlights practical applications, challenges, and the life-cycle assessment (LCA) of MFCs. Despite the promising biotechnological development of MFCs, great efforts should be made to implement them in a real-time and commercially viable manner.

The increasing demand for avocado consumption has led to a vast generation of waste products. Despite the high nutritional value of avocados, the waste generated from their processing poses a significant environmental challenge. Therefore, the development of a sustainable approach to avocado waste management is a major concern. Biorefinery presents a promising approach to the valorization of avocado waste components, including the seed, peel, and pulp residues. This paper explores the potential of avocado waste biorefinery as a sustainable solution to produce bio-based products. Several approaches, including extraction, hydrolysis, fermentation, and biodegradation, to obtain valuable products such as starch, oil, fiber, and bioactive compounds for food or feed goods have been proposed. The review also highlights the approaches towards addressing challenges of energy security and climate change by utilizing avocado waste as a source to produce biofuels such as biogas, biodiesel, and bioethanol. In conclusion, the development of avocado waste biorefinery presents a promising avenue for sustainable development. This process can efficiently convert the avocado waste components into valuable bio-based products and clean energy sources, contributing to the attainment of a circular economy and a more sustainable future.

Thermogravimetric analysis (TGA) is becoming popular for the evaluation of biomass to determine the content of ashes, volatiles, and fixed carbon and to simulate pyrolysis, gasification, and combustion processes. This analysis consists of heating a sample recording the weight variation as the temperature increases over time. The final temperature of the analyzes is usually set at 550 °C or 900 °C. The aim of this paper is to use the intermediate weight values obtained in short times from heating process in TGA to calculate the percentage of volatile, ash, or the residual mass remaining at the end of the experiment. Under the hypothesis that the curve does not vary when the analysis is carried out under certain conditions for the same type of biomass, these values must be similar and are related to the searched values. Nevertheless, given that the behavior of the thermogravimetric curves can be influenced by different factors, such as the species, temperature variation with time, final temperature reached, and presence of leaves, these factors are analyzed in this article. The results show models developed for the ash and volatiles determination from TGA time reduced to 75 s when a temperature increase of 200 °C per minute is used (CR-200 and VR-200 models). The curves obtained have R2 coefficients of between 0.75 and 0.95, being validated through independent samples. It is shown that the plot of the curve is influenced by the composition, the rate of heating and the percentage of leaves. This variability makes it necessary to select an analytical method that is efficient and as brief as possible. In this article, rapid analyses combined with the application of the equations obtained are proposed.

To ensure the long-term viability of a circular bioeconomy based on native forests, it is crucial to enhance our understanding and overcome existing disparities in knowledge and application throughout the entire value chain of forest products. The objective of this article is to contribute towards this goal and facilitate the proper management of forest biomass. Firstly, a methodology is proposed for the study of biomass throughout the native forest value chain, identifying the main steps, criteria, and variables to consider. This approach is evaluated through a case study in Argentina, where over 2370 tons of biomass are wasted annually. A series of strategies for analyzing the most suitable uses and applications for this biomass are examined. Finally, some key approaches for the promotion of a circular and sustainable forest bioeconomy are identified. While it is true that there is still a long way to go before small rural economies can make a more efficient and comprehensive use of their resources (potentially including small biorefineries) with appropriate cascade use schemes, moving towards biomass energy use constitutes a practical and concrete alternative today. This proposal provides tools for accelerating this necessary ecological and energy transition.

The energy use of residues from agriculture, forestry, and solid waste can foster the transition towards a more renewable energy supply. This paper analyzes the energy potential of the above-mentioned sources for energy applications in Kosovo. The analysis is based on statistical data from different studies and reports, analyzing and calculating them to determine the theoretical and energy biomass potential. Kosovo can increase its self-sufficiency by taking advantage of its rich but under-utilized potential of biomass energy sources. This is a novelty study in this area, considering Kosovo lignite-dominated heat energy and electricity consumption and the available special literature. According to our estimates, the theoretical potential is 6.13 million tons/year, while the biomass energy potential should be around 4.57 million tons/year, including approximately 74.6% of biomass, which can be used for energy needs (heating and electricity). Based on the data and calculations, the available and usable potential shows biomass as an energy source with high potential in Kosovo; its share is very low, but it is reasonable to grow for both environmental and economic reasons.

This study describes an investigation of the pyrolysis and combustion of flax straw as biofuel, focusing on the physicochemical properties and kinetic and thermodynamic parameters, and evaluates the type of degradation products using the thermogravimetry analysis–Fourier transform infrared spectroscopy (TGA-FTIR) technique. Pyrolysis and combustion processes were studied via thermogravimetric analysis at different heating rates of 5-10-15 and 20 °C min, one using three isoconversional methods and one using a model-fitting method. The activation energies, frequency factors, and thermodynamic parameters of flax straw biomass were investigated using different models. The obtained activation energy values for pyrolysis varied between 101.0 and 109.6 kJ mol−1 and for combustion were between 203.3 and 239.2 kJ mol−1. The frequency factors were determined to be 1.7 × 109 for pyrolysis and 1.5 × 1017 s−1 for combustion. The change in Gibbs free energy (ΔG) for the pyrolysis of flax straw was calculated to be 162.6 kJ mol−1, whereas for combustion it increased to 203.9 kJ mol−1. A notable contrast between the volatiles produced by pyrolysis and combustion is evident from the real-time analysis of the degradation products. Specifically, carboxylic acids, aromatics, alkanes, and alcohols are the principal degradation products during pyrolysis, while carbon dioxide is the primary component produced during combustion. These encouraging research outcomes regarding flax straw pyrolysis and combustion can broaden its application in bioenergy and biofuel, thus contributing significantly to it for resource recovery.