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[Display omitted] • Marine emission possesses both environmental and human health risks. • Alternative fuels including hydrogen can reduce harmful emissions from marine transport. • Alternative fuels have the potential to promote UN Sustainable Development Goals. • The potential challenges of alternative fuel in marine transport are highlighted. The International Maritime Organization (IMO) has placed stricter controls on several aspects of global maritime transport operations to protect the environment. In light of this, the goal of this study is to examine and assess the different prospective paths and technologies that will assist the shipping industry in decarbonizing its operations. We consider how the utilisation of various alternative energy sources reduces greenhouse gas (GHG) emissions from marine transportation and contributes to the promotion of the United Nations Sustainable Development Goals (SGDs). The complexities associated with maritime industry operations using alternative energy sources are also explored. Biofuel as an alternative energy source, including biomethanol and biodiesel, can reduce greenhouse gas emissions in the shipping industry by 25% to 100%. However, the current supply of biofuels can only meet about 15% of the total demand which is not sufficient to sustainably power the entire marine fleet. There are several issues associated with these biofuels, including oxidation, ecological consequences, feedstock availability, technical and operational constraints, and economic factors that must be addressed before their full potential may be achieved. [ABSTRACT FROM AUTHOR]

Abstract: The global energy consumption is expected to grow in a faster rate than the population growth. By 2030, an increase of 53% of global energy consumption and 39% of greenhouse gases emissions from fossil fuels is anticipated. Therefore, it becomes a global agenda to develop clean alternative fuels which are domestically available, environmentally acceptable and technically feasible. As an alternative fuel, biodiesel seems as one of the best choices among other sources due to its environment friendly behavior and similar functional properties with diesel. The main objective of this paper is to discuss the impact biodiesel from different edible, non-edible and waste cooking oils feedstocks on combustion characteristics, engine durability and materials compatibility with biodiesel. Moreover, this paper reviews some other important related aspects to biodiesel such as biodiesel development, biodiesel feedstocks, biodiesel standards and advantages and challenges of biodiesel. [Copyright &y& Elsevier]

Abstract: Global energy demand is increasing due to the population growth and industrialization. In order to fulfill the energy demand with considering global concern, it is necessary to find out alternative fuel sources. Biodiesel is one of the best choices because of its immense potential to be part of energy mix in the near future as well as the capability of reducing greenhouse gas emissions. This paper aims to provide information to the engineers, industrialists and researchers who are interested on biodiesel. The paper presents a comprehensive review on the impact of potential biodiesel feedstocks (edible and non-edible) on engine performance and exhaust emissions including details of engine and operating condition. A large number of literatures from highly rated journals in scientific indexes are reviewed including the most recent publications. Most of the authors showed that using biodiesel from various feedstocks in diesel engines slightly lowered brake power and brake thermal efficiency but increases BSFC than diesel fuel. It was also reported that biodiesel significantly reduced the PM, HC, CO and CO2 emissions but gives slightly higher NO x emissions. It was shown that NO x can be reduced by some approaches such as blending with additives and EGR technique. The study concluded that biodiesel can be used in compression ignition engine with no or minor engine modification. Finally biodiesel can be used as a substitute of diesel fuel to fulfill the energy demand, reduce dependency on fossil fuel as well as the exhaust emissions of the engine. [Copyright &y& Elsevier]

Abstract: Among the alternative fuels the Bio diesel is one the most common and familiar to all. It''s biodegradable, environment friendly as well as suitable source, to meet the future energy crises. The main concern of this experimental analysis is to reach a tentative goal, how this fuel can be utilised with maximum effective way. To find this,an experiment data analysis of different parameter such as break power, break specific fuel consumption, emission characteristic(NOx, HC,CO. etc) and exhaust temperature, is done through bio diesel fuel and also compared with ordinary diesel which is also known as petro diesel. This investigation is carried out through eddy current dynamometer and load cell arrangement which is controlled by a computer in case of finding the break power and BSFC respectively. And the emission characteristics are observed using Bosch and Bacharach exhaust analyzers. And finally the result is compared with diesel engine which is run by ordinary diesel. The final result implied that the bio diesel with some additives (B20+1%) shows best performance and reduce the exhaust emission including NOx.Thus the decision may be taken,20% blended bio diesel with 1% additive as a best alternative fuel considering all the view aspects and alternatives. [Copyright &y& Elsevier]

The utilisation of available renewable resources and mitigating their impact on the environment boosts sustainable development and helps to achieve the United Nations Sustainable Development Goals. Biogas is a renewable energy option produced through anaerobic digestion of wastes such as livestock excreta and slaughterhouse wastes. Biogas production is treated as one of the leading processes to combat climate change as well as a waste management strategy, especially for a developing country like Bangladesh. It is also vital in meeting future demand for energy utilising indigenous sources. Livestock farming is an important economic activity in rural areas of Bangladesh. Thus, the livestock waste production, estimated biogas generation capacity, electricity generation potential, greenhouse gas (GHG) reduction potential, and estimated biofertiliser generation capacity of Bangladesh were determined for the financial year 2018–2019 in this study. The results show that Bangladesh had 486.77 million tons per year of animal waste products to produce 27,923.72 million m3/year biogas in 2018–2019. This biogas potential corresponds to a theoretical potential to produce a 512 PJ/year heating value and electric power of 50 TW h/year. Besides, about 29.232 million tons per year of organic fertiliser can be produced with the residues of the biogas plants. The findings of this study will contribute to guiding policymakers and governments who will concentrate on the use of animal waste in biogas industries and livestock farming as a potential bioenergy source to meet national energy demand. [Display omitted] • Biogas potential and GHG emission reduction capacity of livestock waste were estimated. • Animal wastes of Bangladesh have the potential to generate 27,923.72 million m3/year biogas. • The produced biogas can generate a heating value of 512 PJ/year and electric power of 50 TW h/year. • About 29.232 million tons/year of biofertilizer can be produced with residues of the biogas plant. [ABSTRACT FROM AUTHOR]

• Food waste is a potential source of sustainable gaseous biofuel. • Anaerobic digestion is an efficient technology to convert food waste into fuel. • Turning food waste into energy can assist the decarbonisation of the economy. • Converting food waste into sustainable fuel can significantly lower the GHG emission. Food waste is a type of organic waste generated by restaurants, food processing plants, households, and commercial and institutions. This study aims to assess the sustainable biofuel, electricity production and greenhouse gas emission reduction potential of food waste using anaerobic digestion technology. Food waste data was collected from the Australian government database to estimate the biomethane and biogas yield and to evaluate the opportunities to convert the biomethane into electricity and heat. This study found that food waste can yield 47% biomethane and hence for Australia, an estimated total of 0.07 million m3 to 1.54 million m3 of biogas can be produced and up to 414,898 tonnes of greenhouse gas emissions reduced annually. The study also estimated that the generated biogas can replace fossil fuel-based electricity generation of up to 52.36 GW and 554.4 TJ heat per year. The environmental assessment indicated that the complete conversion of food waste can lower greenhouse gas emissions (GHG) by up to 5,07,434 tonnes per year and Australia can earn about $52.38 M revenue from electricity production. Therefore, conversion of food waste into biofuel through the anaerobic digestion process can play a significant role in generating electricity from non-fossil-based sources, reducing GHG emissions and earning revenue. [ABSTRACT FROM AUTHOR]

Abstract: Biodiesels are gaining more importance as a promising alternative energy resource. Engine performance and emission characteristics of unmodified biodiesel fueled diesel engines are highly influenced by its ignition and combustion behavior. This review article presents the literature review on ignition delay (ID), combustion and emission characteristics of biodiesel fueled diesel engine. More than hundred articles report which have been published mostly in the last decade are reviewed in this paper. The investigation results report that the combustion characteristics of bio fueled engine is slightly different from the engine running with petroleum diesel. Most of the investigation results have reported that as compared to diesel, biodiesel has early start of combustion (SOC) and shorter ID of between 1–5° and 0.25–1.0°, respectively. Higher cetane number (CN), lower compressibility and fatty acid composition of biodiesel have been identified as the main elements for early SOC and shorter ID. In addition, it is also found that, the heat release rate (HRR) of biodiesel is slightly lower than diesel owing to the lower calorific value, lower volatility, shorter ID and higher viscosity. [Copyright &y& Elsevier]

This article aims to comprehensively review the anaerobic digestion (AD) process utilising the organic fraction of municipal solid waste (OFMSW) substrate. The AD of OFMSW has received considerable attention due to its significant energy and nutrient recovery as well as its greenhouse gas (GHG) mitigation potential. AD is a biological process involving treating and stabilising organic matter in the absence of oxygen accomplished by a consortium of microorganisms and occurs under hydrolysis, acidogenesis, acetogenesis, and methanogenesis phases. The hydrolysis phase is recognised as the primary rate-limiting step. Thus, exploring the ways to speed up the hydrolysis process will maximise biogas production. The key factors affecting the digestion efficiency include feedstock quality, pre-treatment process, design and selection of digestion process and process conditions including pH, temperature, carbon to nitrogen (C: N) ratio, organic loading rate and hydraulic retention time. The review reveals that solid-state anaerobic digestion (SSAD) is best suited for OFMSW due to its high solid concentration (>15%) and better process performance. The continuous digestion with thermophilic temperatures was found to be the best condition for high solid AD process. The plug flow and continuous stir tank reactors were the best performing options to control the biological conditions for the digestate post-treatment. Proper selection of the parameters for the whole process is crucial in ensuring process feasibility and economic sustainability of AD of OFMSW. The study revealed that the AD of OFMSW could play a significant role to mitigate waste and waste-related problems. • Studies on organic fraction of municipality solid waste are reviewed. • Pretreatment is required to achieve optimum results in anaerobic digestion. • The digestion operating conditions significantly controls the biogas output. • The products of digestate require post-treatment for maximised output. [ABSTRACT FROM AUTHOR]