Experimental development of biodiesel fuel derived from freshwater microalgae for improved engine performance and reduced emissions

This study is conducted to research the production of biodiesel from Chlorella vulgaris microalgae and its feasibility as a renewable, low-emission alternative to fossil diesel fuel. Test results of the biodiesel in a single-cylinder diesel engine show a 60 % decrease in CO₂ emissions and a 20 % reduction in NOx emissions at various operating loads and speeds. It also yielded consistent results in terms of engine efficiency, with only slight power trade-offs at high-load scenarios—an indication that this biodiesel is compatible with conventional diesel engines. Further, by GC-MS detailed analysis for validation of the chemical composition and purity of the biodiesel, it indeed contained major fatty acid methyl esters, including methyl oleate, methyl linoleate, methyl palmitate, and methyl stearate. These results affirm the conformity of biodiesel to the requirements of industry standards and support its feasibility as a clean, renewable fuel. This study contributes to the dual environmental and performance benefits of microalgal biodiesel and underlines its place in sustainable energy systems and carbon footprint reduction. • A semi-industrial technique for extracting biodiesel from Chlorella vulgaris was developed. • The use of this biodiesel in a diesel engine has lowered CO 2 _emissions by 60 % and NO X emissions by 20 %. • A substantial amount of these emissions were achieved over a long period of time with biodiesel, indicating possible long term usage of the engines. • The research demonstrates that microalgal biodiesel can act as a suitable substitute for fossil fuels.