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The energy demand in Malaysia has shown a dramatic increase over the last few years: with natural gas and coal being the primary contributors. Nevertheless, due to declining in fossil fuel reserves coupled with negative environmental impacts, shifting to sustainable renewable energy for meeting the future energy demand is recommended. Since Malaysia is rich with natural resources, utilization of biomass energy (bioenergy/biofuel) as the alternative energy is promising to be further explored. Therefore, this review paper intents to discuss the current scenario of different types of biomass energy in Malaysia along with the up-to-date local biomass energy–related environmental policy (from 2016 onwards). In addition, challenges and barriers for large-scale implementation of the biomass energy in Malaysia are to be discussed. Overall, this review paper is interesting as it can assist in promoting the biomass utilization as energy source, and to ensure the future growth of biomass energy market in the country along with its effective implementation while alleviating poor disposal problem and to create job employment opportunities. Furthermore, a collective effort to expand potential biomass feedstocks, apart from oil palm, should be emphasized to encourage the renewable energy production diversification in the nation. [ABSTRACT FROM AUTHOR]

Year after year, there are alarming data concerning the excessive release of greenhouse gases into the atmosphere, especially CO2 from the burning of fossil fuels. In this context, the development of renewable energy sources has evolved considerably, mainly due to the incentive use of biofuels, such as bioethanol. The second-generation bioethanol production from lignocellulosic biomasses has interesting potential to meet this energy demand. The Eucalyptus tree stands as a primary example of cultivated hardwoods, owing to its lignocellulosic structure and the biomass residues generated during its processing, where these attributes make it a significant candidate for the production of fuels. The industrial potential of these materials can be explored in the fractionation of their components to reduce their recalcitrance due to the triad formed by cellulose, hemicellulose, and lignin, for further processing and obtaining the products of interest. This paper comprehensively gathers the current technological progress employed for processing Eucalyptus wood biomasses for second-generation bioethanol production. Discussion regarding their chemical composition, the main forms of pretreatments that are being applied, and ways to minimize the generation of fermentative inhibitors during these processes is addressed. Finally, recent researches focused on Eucalyptus biomass-based bioethanol production and techno-economic considerations are discussed. The feasibility of the process is closely tied to the comprehensive utilization of products derived from this biomass. While production appears relatively effective at the laboratory scale, further research is required to develop a cost-effective process that fully harnesses the potential of the biomass. [ABSTRACT FROM AUTHOR]

Bioethanol is expected to have a major contribution to transportation fuel consumption; hence, environmental analyses are crucial tools to evaluate its environmental performances. In this paper, a life cycle assessment is carried out to study the environmental performance of a bioethanol production system from Tunisian waste dates. The life cycle foreground data were derived from process simulation, while the background data were provided by the Ecoinvent 3.3 database. The impact assessment method applied is the ReCiPe midpoint (H). Seven environmental impact categories are discussed in detail in the interpretation section: global warming, acidification, eutrophication, agricultural land occupation, water depletion, cumulative energy, and cumulative exergy demands. The results indicate that 1 MJ of bioethanol produced from waste dates generates approximately 0.07 kg CO2-eq, which appears comparable with second-generation bioethanol production. One MJ of bioethanol requires approximately 1.087 MJ-eq of primary energy consumption of which 1.065 MJ is nonrenewable. The electric power generation process is the main contributor to most of the environmental impact categories (process hot spot). Therefore, it is strongly recommended to rely on renewable electricity generation to ensure relevant environmental improvements. [ABSTRACT FROM AUTHOR]

Biomass represents 10% of the total energy use and 55% of all renewable energy in Mexico. It is a key energy source to help Mexico achieve a low-carbon development path to comply with the strict climate mitigation targets needed to avoid catastrophic consequences. However, a major limitation in the construction of reliable future mitigation scenarios is the lack of information regarding in-country greenhouse emission factors associated to both traditional and modern bioenergy devices. This paper aims to close this gap, providing detailed estimates of energy and emission factors from bioenergy devices in the Mexican residential and industrial sectors. In particular, four energy tasks, comprising 67% of current bioenergy use in the country, were selected (charcoal production, biomass drying, space heating, and cooking) with a total of nine bioenergy devices: traditional earth mound charcoal kiln, flash dryer, heater, five types of cookstoves, and an open fire. The thermal efficiency ranged from 10 ± 1 to 26 ± 5% for the cooking devices, 95 ± 1 to 96 ± 1% for the space heater, 34 ± 8% for the charcoal kiln, and 10 ± 2% for the biomass dryer. The modified combustion efficiency was calculated to be 88 ± 1% for the earth mound charcoal kiln, 96–98% for the cookstove, and 93–98% for the space heater. The products of incomplete combustion ranged from 21 ± 6 to 48 ± 12 g for the cooking devices and 58 ± 18 to 340 ± 107 g for the space heaters. CO2 emission factors ranged from 102 ± 2 to 119 ± 2 g/MJ for the local biomass stoves. Relative to other pollutants, the CO emissions per energy unit were the highest, ranging from 1193 ± 184 mg/MJ for the space heater to 18,121 ± 1232 mg/MJ for the earth mound charcoal kiln. The total global warming potential was estimated to be 35 ± 2 gCO2e/MJ for the ONIL stove (modified) and 158 ± 4 gCO2e/MJ for the earth mound charcoal kiln. The estimates presented in this study represent an important contribution to Mexico's inventories in terms of energy performance and emissions parameters of four energy tasks in the industrial and residential sectors. This information will be a baseline to estimate carbon footprint, life cycle assessments, GHG emissions scenarios, and mitigation strategies for local and regional Mexican conditions. [ABSTRACT FROM AUTHOR]

In this paper, the regions where Cynara cardunculus L. is cultivated in Turkey are revealed, with data obtained from several locations in Turkey. Furthermore, the installation of active biogas plants in these regions has been identified, and the utilization of Cynara cardunculus L. residues as a biomass source, particularly in Izmir biogas plants, has been investigated. To begin, the amount of Cynara cardunculus L. cultivated in the world and Turkey has been determined. According to the Food and Agriculture Organization of the United Nations (FAO)'s recent data for 2019, approximately 1.6 million tons of Cynara cardunculus L. were produced globally, with Turkey accounting for nearly 2.5% of this quantity. The data from the Biomass Energy Potential Map for Turkey (BEPA) was reviewed, and it was calculated that approximately 40 thousand tons of Cynara cardunculus L. are produced in Turkey each year. Furthermore, the agricultural production of this crop in Turkey generates roughly 225 thousand tons of residues. In comparison to other regions, the Izmir region generates 32.5% of Turkey's Cynara cardunculus L. residues. However, no research on the evaluation of this residue potential and the utilization of Cynara cardunculus L. residues in biogas production has been conducted to date. As a result, it was aimed at the residual potential of Cynara cardunculus L. in various regions of Turkey, as well as its potential utilization as a biomass resource for biogas plants in these areas. It has been calculated that 1.65% of the Izmir population could supply its energy demands by utilizing the energy equivalent of the Izmir region's wastes. [ABSTRACT FROM AUTHOR]

The paper evaluates the relation between energy input (Ei) and output (Eo) of biogas production from six energy crops: maize, sorghum, sunflower, triticale, reed canary grass (RCG), and Virginia mallow (VM), cultivated in three different nitrogen fertilization levels. Furthermore, in the case of RCG, the impact of cutting system was examined. The results showed that raised N fertilization dose (in the range of 40–120 kg ha−1 and 80–160 kg ha−1, depending on the crops) increased biomass yield and methane productivity (MP) but simultaneously caused also the increase in Ei. Nonetheless, the application of higher N doses did not cause drastic decrease in energy use efficiency (EUE). The Ei was significantly lower for perennials than for annual crops. For this reason, EUE for RCG harvested in two cuts (5.0–5.2 GJ GJ−1) was close to EUE for maize (5.7–6.8 GJ GJ−1), despite the much lower MP (2027–2903 m3 ha−1 and 4409–5692 m3 ha−1, respectively) and Eo (73–105 GJ ha−1 and 159–205 GJ ha−1, respectively). Furthermore, the collection of RCG in more than two cuts turned out to be unjustified, due to increase in Ei and, simultaneously, decrease in MP. [ABSTRACT FROM AUTHOR]

Melons belong to the Cucurbitaceae family and are grown in the tropical and temperate regions of the world. With numerous identified varieties, melons are regarded as one of the most economically important vegetable crops. 'Egusi' melon, one of the most popular members of the melon family with diverse species, has formed a significant part of the diet of many Africans and Asians. Egusi melon seed kernels are a good source of edible oil (31–59%), protein (19–37%), fibre (3–4%), and carbohydrate (8–20%). The objectives of this review are to highlight the food uses of egusi melon and its prospect for biodiesel production. Firstly, an introduction to egusi melon is presented, describing its origins, varieties, cultivation and yield, followed by an extensive review of the nutritional composition, oil extraction methods and analysis and food uses of egusi. Then, the engineering properties of egusi fruits, seeds and kernels and the energy utilisation of its biomass are shown. This review also covers the use of egusi seed kernel oil for biodiesel production, the rheological properties of egusi biodiesel, its engine performance, emission characteristics and the conformity of the biodiesel to standard specifications. Finally, future challenges and research directions are presented. This paper will prove to be a viable resource for the food, energy and automobile industries, as well as the scientific community. [ABSTRACT FROM AUTHOR]

Straw management is extremely challenging, and irrational treatment can cause environmental pollution and affect the development of a circular economy in agriculture. The high-value utilization of agricultural straw as an important pathway to promote circular economy and achieve carbon neutrality goals has attracted much attention. Herein, the environmental and economic performance of the main straw-based fuel (straw-to-biochar, ethanol, and biogas) and material (straw-to-board and paper) utilization scenarios in China were compared from a life cycle perspective. This study is based on data from the eFootprint platform and the China Life Cycle Database. The results show that straw production for fuel has a better environmental performance than the production of materials option for water use, acidification potential, eutrophication potential, and respiratory inorganics. Utilizing straw to produce fuels or materials can reduce greenhouse gas emissions by 155–1296 kg CO2 eq. and decrease primary energy consumption by 8949–31270 MJ. Straw-to-board has the worst energy conservation and emission reduction performance but has the best economic performance with an LCC value of − 46.38 USD. The scenario with the shortest payback time is straw-to-ethanol, which take only 2 years. Sensitivity analysis reveals that the product has the most significant impact on the environmental and economic performance. The study analyzed the environmental impacts and economic benefits of these straw utilization pathways to provide solutions for sustainable straw management. [ABSTRACT FROM AUTHOR]

This work presents a conceptual design of an integrated biorefinery using olive tree pruning as feedstock. The biorefinery combines a state-of-the-art thermochemical technology for producing high value-added antioxidants with an energy self-sufficient biochemical platform for lignocellulosic ethanol production. These plants are integrated by exchanging energy and feedstock. The process and design parameters employed in the plant designs are based on the authors' own lab and pilot-scale data. The paper discusses the economic dilemma of using this feedstock for producing high value-added products in small amounts versus producing large amounts of low-profit biofuels. The feasibility of this production strategy at medium scale is demonstrated via a techno-economic analysis based on total production cost for each co-product. Each plant is energy integrated, and the energy performance of the bioethanol plant is assessed by calculating the end-use-energy ratio. Both analyses are parameterized with respect to plant capacity (100-1500 t dry weight (dw)/day) and raw material price (20-100 €/ton dry weight). [ABSTRACT FROM AUTHOR]

In the direction of sustainable and zero carbon energy production, hydrogen is considered as a potential fuel with high heating value and energy content compared to other fossil fuels. The present review focuses on conventional and advanced biohydrogen production by utilizing low-cost biomass feedstock through dark fermentation, photo fermentation, bio-photolysis, microbial electrochemical cell, as well as integrated and co-fermentation approaches. Different substrate pretreatment methods, such as thermo-aero-size reduction, acid–alkali or biocatalyst, and combined pretreatment methods are investigated, which can potentially enhance hydrogen productivity multiple-fold. This review explores the application of various hydrogen-selective polymeric membranes, which improves biohydrogen production yield and reduces purification costs. Techno-economic assessment of different biohydrogen production technologies is reviewed based on technological advancements for improved production yield and energy efficiency as well as economic performance enhancement depending upon a minimum selling price, capital cost, operating cost, and profitability. Furthermore, an extensive investigation of the continent or country-specific biohydrogen production challenges is presented. These findings of the current study will explore novel biohydrogen production processes with an aspect of energy efficiency, economics, and environmental footprint. [ABSTRACT FROM AUTHOR]

Detailed studies about energy content and chemical characterization of biomass alternatives are necessary to determine their main features as solid fuels. The aim of this study was to analyze and compare the properties of five types of residual biomass pellets produced throughout Mexico: sawmill pine waste (SPW), spent ground coffee (SGC), pecan nutshell (PN), oil palm waste (OPW), and mango waste (MW). Conventional characterization analyses revealed significant differences in HHV (21.44–17.37 MJ/kg), elemental composition showed a lower carbon content in SPW and MW (around 46%), OPW (close to 47%), and higher carbon content in PN and SGC (around 51%). The concentration of the main structural polymers showed notable significant differences (p < 0.05) too: 49–17% for cellulose, for hemicellulose 21–5% and for lignin 26–4%. High-throughput instrumental techniques were also used: FTIR provided additional information on chemical composition in pellets on which lignocellulosic biomass was not predominant, presence of pectins and starch in MW, and high content of fatty acids in SGC and OPW; TGA showed different thermal stability of pellets in the combustion process, where OPW and SPW presented the lowest and highest thermal stability, respectively, while XPS showed different types of bonds between C and O in the surface of materials with a relevant presence of bonds associated to lignin covering PN and SPW. Based on results of this investigation, a possible rank for the energy use of these five biomasses is suggested: PN, SPW, SGC, OPW, and MW, but future deep research is necessary that incorporate other relevant attributes, mechanical properties, emission profiles, corrosion, and slagging effects. [ABSTRACT FROM AUTHOR]

Economic and social development around the world has contributed to increased energy demands, which have strained the energy supply chain. The global energy matrix depends on the exploitation of fossil fuels, which are responsible for disastrous social, political, and environmental impacts. This situation has led to the need for technological advances in the development of new sources of safe, renewable, and sustainable energy production. In recent years, biomass has gained importance among emerging sources of energy production due to its abundance and renewable nature. Therefore, this study reviews the availability and physicochemical properties of unexplored Amazonian biomass sources, which, in principle, neither compete with food production nor have disastrous environmental impacts on the Amazon forest. This review also focuses on thermochemical conversion methods for possible application of the biomasses under study to produce electricity for geographically isolated communities in the Amazon, whose electricity comes from generators powered by diesel oil, a nonrenewable and relatively expensive resource. The information provided in this article is important for the formulation of alternative and renewable energy government policies for the Amazon region, in addition to presenting a scientific study of the main biomass available in the region, including thermochemical characteristics for energy conversion. [ABSTRACT FROM AUTHOR]

Indonesia ranks fourth as the most populous nation after China, India, and the USA and is one of Southeast Asia's most significant energy users. Due to the rapidly increasing energy consumption and depleted fossil fuel production, Indonesia has become a net importer of oil since 2004. To mitigate the challenge, a policy concerning the utilization of biodiesel as a fossil fuel substitute was firstly launched in 2006. Starting from 2020, the Government of Indonesia issued the mandatory program of biodiesel called B30, making Indonesia hit the record as the highest implementer of biodiesel in the world. However, an in-depth study of the current status of Indonesia's palm biodiesel has not been reported well. Therefore, this study aims to comprehensively review the current situation and challenges of biodiesel implementation in Indonesia. Here, Indonesia's energy policy and the current status of Indonesia's palm biodiesel, including the potential of biodiesel resources and techno-economic and socio-political aspects, are comprehensively discussed. Based on the analyses, biodiesel mandatory policy has a significant impact on economic and social aspects. It is projected that the program will increase the labor to 10,182 workers in biodiesel industries and save the foreign exchange at around US$4.46 billion by 2030. Finally, several main challenges faced along with several plausible mitigations to overcome the problems in implementing palm oil biodiesel production are also highlighted. Highlights : Indonesian palm biodiesel program contributes to increasing the NRE portion Biodiesel program has a significant impact on economic and social aspects The program is projected able to increase the labor to 10,182 workers by 2030 The program can save the foreign exchange at around US$4.46 billion by 2030 Sustainable biodiesel must consider diversification of biodiesel feedstock [ABSTRACT FROM AUTHOR]

Eukaryotic microalgae and prokaryotic cyanobacteria can grow in various water and wastewater types, and both can grow biomass by taking nutrients and converting atmospheric CO2 into useful products. Biofuels obtained by processing this landless grown biomass are defined as "third-generation biofuels". In this study, the effects of hydrodynamic cavitation (HC)-assisted NaOH pretreatment on methane production from cyanobacteria were investigated. Cyanobacterial biomass was isolated from thermal springs located in the southwest of Turkey (Denizli-Turkey) and identified as Desertifilum tharense. Desertifilum tharense biomass was grown on a laboratory scale, and along with its compositional characteristics, culture-specific parameters were determined. HC-assisted NaOH pretreatment was applied to evaluate optimum process conditions for enhancing methane production from D. tharense. In the experimental design, process parameters of cavitation number (Cv: 0.3-0.7), NaOH concentration (0–4%), solid content (1.5%), reaction time (4h), and reaction temperature (30°C) were combined to reveal the parameter-specific impact of HC pretreatment. The effect of the HC-assisted NaOH pretreatment was further investigated with molecular-bond and surface structure characterization. Along with the energy equivalent of obtained biofuel, energy requirements for cultivation, harvesting, pretreatment, and anaerobic digestion (AD) were calculated to determine the process's overall energy efficiency. Kinetic parameters of raw and pretreated D. tharense were determined by first-order, cone, modified Gompertz, and reaction curve models. The results revealed that by the application of pretreatment, a 2-35.3% soluble COD increase was achieved, whereas methane production was increased from 241.5 to 290.6 mLCH4 gVS−1. Application of HC with a low Cv of 0.3 boosted methane production up to 20.3% compared to the raw D. tharense. [ABSTRACT FROM AUTHOR]

The use of fruit residues from domestic consumption for energy purposes is a perspective of innovation in the search for a more sustainable fuel, due to the low cost of this biomass, combined with its large amounts of generation, which has sugars readily available in its composition and does not require process pretreatment hydrolysis complexes of the material. This work evaluated residues of melon, pineapple, banana, apple, and mango, to compose a mixture of fruit waste (MFW), simulating a household waste for bioethanol production by a non-conventional yeast Wickerhamomyces sp. UFFS-CE-3.1.2. Sugar extraction was optimized by experimental design (MFW: 12% g dry mass v−1; 25 °C; 5 min) and resulted in the liberation of 36.32 ± 0.72 g L−1 fermentable sugar. MFW was used for alcoholic fermentation with and without nitrogen supplementation (urea and yeast extract). The results demonstrated that it is not necessary for the supplementation, making the process more economically viable. The maximum ethanol productivity (2.50±0.06 g L−1 h−1) was achieved in 9 h of the operation. The MFW extracted is an alternative for the bioethanol process as low cost and straightforward, adapted for different fruit residues, and used as a unique or diluent medium in the biorefinery context. Moreover, non-conventional yeast demonstrated the more new one in this study that explores the potential of yeast recently isolated. [ABSTRACT FROM AUTHOR]

Here, a cost-effective route for the preparation of biodiesel (BD) from waste cooking oil (WCO) as an alternative eco-friendly fuel and lubricant via catalytic transesterification process using simple base catalyst was demonstrated. Physical and chemical characterization based on FT-IR, 1H-NMR, and 13C-NMR spectroscopy reveals that free carboxylic acid functionality successfully alters to methyl ester of same hydrocarbon chain during the reaction. The BD was characterized by its physical, fuel characteristics including density, viscosity, acid value, flash point, pour point, and foaming tendency, and compared with existing diesel fuel in accordance with ASTM test standard. Prepared BD showed excellent fuel efficiency with higher flash (142 °C) and fire point (147 °C) than the existing diesel fuel. In order to use these synthetic biodiesel esters as advanced green lubricants, their lubrication behavior was tested and compared with hydrocarbon base oil hexadecane (HD). The macrotribological results showed the biodiesel significantly reduced the coefficient of friction by a maximum ~ 43% and specific wear rate ~ 71% in comparison with that of HD at variable applied load. The lubricating efficiency of prepared BD was found to be a similar trend in microtribometric experiments with reciprocating sliding motion under variable loads with similar contact pressure (Pm ~ 1.36–1.95 GPa) as demonstrated in macrotribological rotating motion. Due to polar nature of biodiesel, it deposits on the contact interface and provides a thick molecular film, which may be responsible for enhanced tribological behavior compared with pristine hydrocarbon oil. [ABSTRACT FROM AUTHOR]

Lipid extraction from microalgal biomass faces some challenges such as the selection of a suitable biomass type and its quality, lipid yield (LY), and process energy consumption. This study aimed to develop optimized processing conditions using response surface methodology, for the ultrasonic extraction (UE) of lipids from wet and dried marine Chlorella sp. Integrated process approaches with different extraction and solvent recovery steps were developed for the evaluation of the lipid recovery and process energy consumption. The effects of other processing factors, such as the biomass-to-solvent ratio, solvent type, and solvent-to-solvent ratio were investigated. The biomass and lipids extracted were characterized by scanning electron microscopy-energy-dispersive X-ray (SEM-EDX) and gas chromatography-flame ionization detection (GC-FID) analysis, respectively. With a single extraction and single-solvent recovery (1-1 cycle) process, the LYs from fresh and stored paste were 11.7% and 6%, respectively, while freeze-dried biomass produced an 18.5% LY. The energy consumption was 6000 MJ/kg lipid for the wet route and 8200 MJ/kg lipid for the dry route in the 1-1-cycle process. Dried biomass was selected for further investigation due to its longer storage-period capability and higher LY. The LY of the 2-1-cycle process using methanol/hexane (2/1 v/v) with a biomass-to-solvent ratio of 1/20 g/mL was 31% and was considered as a base case scenario of this study, which is 40.3% and 9.7% greater than those of the 1-1 cycle and 2-2 cycle, respectively. The lipids obtained from the 2-1 cycle at the optimum condition were mainly saturated fatty acids which are suitable for a biodiesel feedstock. [ABSTRACT FROM AUTHOR]

Grass ley and whole-crop cereals used for biogas production are often finely chopped for subsequent ensiling and anaerobic digestion. Chopping can impact not only ensiling stability, digestibility and risk of process hick-ups in the digester but also harvesting capacity and fuel consumption. Based on field experiment data, the aim of this study was to investigate how three different nominal cutting lengths in the range of 3.5 mm to 12.5 mm impact methane yield and economic viability of grass ley and whole-crop cereals used as biogas substrate. A shorter cutting length affected the specific methane potential differently for the different crops, + 14 to − 25%. In biogas vehicle fuel production, balancing the additional energy and economic costs for shorter cutting length required an increased methane potential of less than 1% and 3%, respectively. As long as a decrease in cutting length increased the methane potential, the energy balance and economic result improved, despite higher energy inputs. However, mechanisms behind the impact on methane potential deserve further attention. In conclusion, we have shown that it is economically viable to produce methane gas, as a vehicle fuel, from several agricultural crops grown in the south of Sweden, i.e. grass ley and whole-crop rye and wheat, when they are harvested/chopped with a forager, ensiled as biogas feedstocks and processed to methane gas in a large-scale biogas plant. [ABSTRACT FROM AUTHOR]