The increasing global energy demand and environmental concerns associated with conventional fossil fuels have accelerated scientific interest in renewable alternatives. Among the available renewable options, biofuels derived from agricultural waste present a promising pathway to reduce carbon emissions, enhance waste utilization, and support regional energy security. This study focuses on the production efficiency and emission characteristics of biofuel generated from agricultural residues, particularly lignocellulosic biomass such as rice husk, corn stover, palm oil residues, and sugarcane bagasse. The overarching aim is to assess how agricultural waste can be transformed into viable biofuels while maintaining economic and environmental sustainability.
Agricultural waste represents an abundant yet underutilised resource, especially in regions where farming activities dominate national economies. Large quantities of biomass are produced annually and typically subjected to open burning or natural decomposition, leading to methane release, particulate matter formation, and soil nutrient degradation. Converting these waste streams into biofuel offers dual benefits: waste reduction and renewable energy generation. However, key challenges remain in optimising conversion processes, improving energy yield, and minimising emissions during production and end-use combustion. This study examines these challenges by comparing three main conversion pathways—thermochemical, biochemical, and transesterification processes—and evaluating their associated performance indicators.
The experimental component involves conducting controlled pilot-scale production trials using selected agricultural residues. Each biomass sample undergoes pre-treatment and moisture control before being processed through gasification, pyrolysis, or anaerobic digestion, depending on the fuel type produced. Gasification mainly yields syngas, pyrolysis produces bio-oil and biochar, while anaerobic digestion generates biogas rich in methane. Parameters such as reaction temperature, catalyst type, particle size, and oxygen supply are modified to determine the conditions that provide maximum yield. Initial results demonstrate that catalytic pyrolysis using palm kernel shells yields higher bio-oil volume compared to rice husk due to its higher lignin content, which enhances thermal breakdown. Similarly, biogas generation rates from sugarcane bagasse indicate a methane composition exceeding 60%, making it a viable substitute for liquefied petroleum gas.
In addition to production efficiency, this research investigates the emission profile of the produced fuels. Combustion testing is carried out in controlled laboratory burners and small-scale internal combustion engines. Emission factors measured include carbon dioxide, carbon monoxide, nitrogen oxides, particulate matter, and unburned hydrocarbons. Preliminary findings reveal that biofuel combustion generally produces lower net CO₂ emissions compared to fossil diesel, due to the carbon neutrality principle of biomass. However, certain biofuels exhibit higher NOx formation, mainly attributed to elevated combustion temperatures and nitrogen content in the feedstock. Bio-oil derived from pyrolysis shows slightly higher particulate emissions due to incomplete volatilisation, which indicates that post-treatment and upgrading processes may be required to meet strict air-quality regulations.
The study also evaluates lifecycle environmental benefits by comparing greenhouse gas emissions across fuel production, processing, transport, and combustion stages. Results suggest that agricultural waste-based biofuels can reduce total lifecycle emissions by up to 75% relative to fossil fuels, depending on conversion technology and local resource availability. Economic considerations are also explored. Cost modelling indicates that agricultural biomass fuels become financially competitive when feedstock is sourced locally, processing systems are modular, and government incentives support infrastructure development.
In conclusion, this research confirms that agricultural waste has the strong potential to be a sustainable feedstock for renewable biofuel production. With growing agricultural output and rising waste generation, biofuel systems can offer decentralised energy solutions, reduce environmental pollution, and contribute to national decarbonisation efforts. Nonetheless, further refinement in conversion technologies, catalyst improvement, emissions mitigation, and fuel upgrading is required before large-scale implementation. The outcomes of this work provide valuable insight into the interplay between fuel efficiency and emission performance, helping researchers, policymakers, and industries build strategies for scaling up agricultural waste-based bioenergy systems.
