Growing demand for energy, the depletion of petrol, the instability of world fuel prices and concerns about global warming are factors that focus the interest in renewable energy sources, bio-energy in-particular. Biodiesel is a form of diesel fuel manufactured from vegetable oils, animal fats, or recycled restaurant greases. It is safe, biodegradable, and produces less air pollutants than petroleum-based diesel. Biodiesel can be used in its pure form (B100) or blended with petroleum diesel.