Biodiesel

Biodiesel is an alternative to diesel fuel that is made from vegetable oils, waste cooking oil, animal fats or tall oil (a waste product from pulp and paper processing). Compared with conventional diesel, biodiesel combusts better and produces fewer greenhouse gas emissions that contribute to climate change.

All vehicles can use blended biodiesel, which is a mixture of petroleum diesel and biodiesel, and many new vehicles can use pure biodiesel. However, some additives are needed in high concentrations of biodiesel, particularly to address cold flow properties during winter months. Research and testing is underway to reduce production costs and address cold weather problems.

What is biodiesel?

Biodiesel is a liquid fuel created from vegetable oils and waste oil products. Before these oils can be used as fuel, they must be processed to make them less viscous, or sticky. Through a process called transesterification, the oil is blended with an alcohol – usually methanol, although ethanol can also be used – and a catalyst such as sodium hydroxide. The resulting chemical reaction produces glycerine and an ester called biodiesel.

Biodiesel can be blended with diesel in any concentration. The blend level depends on economics, availability, the desired emissions level, material compatibility and combustion characteristics. Toronto Hydro and Rothsay/Laurenco fleet vehicles are currently using biodiesel concentrations of 5 percent (B-5) and 20 percent (B-20). Saskatoon Transit Services and Société de transport de Montréal (STM) are also testing B-5 and B-20 in city buses. Technological advances in biodiesel production may reduce its costs.