Recent Update on Biodiesel Production Using Various Substrates and Practical Execution

Worldwide fossil fuel (liquid crude oil-based) demand is projected to exceed 100 million barrel per day by 2040, with diesel dominating by more than 5 million barrel per day. However, dwindling resource, severe ups and downs in crude oil prices, and harmful environmental impact are compelling scientific communities and different countries to look for better and long-lasting substitute renewable and environment-friendly energy fuel. Biodiesel is one such alternative liquid fuel which is almost similar to petro-based diesel and has some critical advantages over it: eco-friendly; suitable to normal diesel engines (either as 100% or as a blend in commercial diesel); and can be synthesized using different renewable resources -- vegetable oils (edible and nonedible), waste frying oil, waste animal fat, algal and microbial oil. It could be produced by almost anyone locally, using either local oil produce or wastes, with almost no major consumables and chemicals, and also easy to separate and store. Based on the characteristics and type of feedstock used, overall production costs are quite low as compared to diesel production. Since it could also be produced from waste oily feedstocks and algal/microbial oils, biodiesel production does not suffer from ``food versus fuel'' dilemma. Worldwide, it is successfully produced both small scales and commercially, and used as a substitute for diesel (pure or blends). Overall, EU and the USA are leading producers and consumers of biodiesel and other countries (Asia, Middle East) are also showing tremendous growth opportunities in the coming years, and may surpass others. Apparent environmental, economic, and social benefits of biodiesel are encouraging both policy makers, stakeholders, and the common public to look forward with optimism that it could be the future of liquid energy fuel.