Liquid Bio-fuels - Biodiesel

Biodiesel is an organic diesel fuel or diesel fuel derived from organic sources. Biodiesel is an alternative fuel to petroleum diesel fuel. Similar to petroleum diesel fuel, biodiesel can be used in diesel engines.

Biodiesel is a clean burning fuel. It is non-toxic, biodegradable, produces 60% less C02 than petroleum based diesel fuel and is free of sulfur and aromatics. It burns better with a higher cetane rating.

Biodiesel fuel is made from:

vegetable oils;
animal fats;
waste cooking oil;
tall oil (derived as a by-product of pulp and paper processing); and
fish oil.

Biodiesel can also be made from grains (e.g. canola and soya beans) and other farm produce. Large scale biodiesel production can be achieved through the growing of several acres of these farm produce to provide feedstock for a biodiesel manufacturing plant. There are arguments that biodiesel production is competing for the crops and lands that we use for food. However, in most parts of the world, there seems to be sufficient land, water and other resources to plant crops for food and biodiesel at the same time. For the complete list of feedstocks for producing biodiesels, click here.

Biodiesel is produced through a chemical process called transesterification. Vegetable oil or other biodiesel producing feedstock is mixed with alcohol (methanol or ethanol) and a catalyst (e.g. sodium hydroxide). The resulting reaction produces two products: methyl esters (which is the biodiesel) and glycerin. Glycerin is used in the manufacturing of soaps and related products, while biodiesel is used to run compression-ignition (diesel) engines.

Recommended books

Do It Yourself Guide to Biodiesel: Your Alternative Fuel Solution for Saving Money, Reducing Oil Dependency, Helping the Planet

Biodiessel can be used in diesel engines with little or no modifications. 100% biodiesel could be used in some vehicles, particularly in hot climates or in vehicles properly designed to heat up the biodiesel fuel to ensure it remains in liquid form always. In cold climates, the biodiesel becomes viscous and can clog up and prevent the engine from running. Generally, most applications use the blended form of biodiesel. The pure biodiesel is blended with petroleum diesel to create a biodiesel blend. Biodiesel blends are denoted as, "BXX" with "XX" representing the percentage of biodiesel contained in the blend.

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B10 blend is 10% biodiesel, 90% petroleum diesel, B100 represents pure biodiesel while B5 represents 5% biodiesel and 95% petroleum diesel and so on. The blend level is determined by economics, availability, the desired emissions level, material compatibility and combustion characteristics and what is allowed or recommended by vehicle manufacturers. Most vehicle engine manufacturers in North America now allow up to a B5 level biodiesel blend while some select manufacturers grant warranty, under specific conditions, up to a B20 level blend.

Using biodiesel as an alternative fuel to petroleum diesel to combat global warming is only of noticeable benefit over the life cycle. Direct greenhouse gas (GHG) emissions are only very slightly lower using biodiesel over petroleum diesel in diesel engines. However, over the life cycle through the growing of the plant feedstocks (e.g. oilseeds plants which serve as carbon sink), redirecting animal and plant wastes capable of ending in landfill and generating more methane GHG gas, there is a significant reduction in GHG emissions. Possible reductions over the life cycle are:

Pure biodiesel	60 to 100% reduction
B20	12 to 18% reduction
B2	1 to 2% reduction

The use of biodiesel also leads to reduction in global warming because the feedstocks or raw materials for producing biodiesel can sometimes be obtained from recycling of wastes - agro-industry residues/wastes such as slaughterhouse waste, recycled cooking oil, non-food-grade virgin oil or agricultural surplus.