The search for new biofuels, producing biodiesel from tallow
Biodiesel can easily be produced from tallow (a rendered form of beef or mutton fat) in processes similar to plant oils. Tallow is referred to in the bible, yet it is most relevant today in the quest for biofuels that don’t require the diversion of farmland and crops. Experts are unanimous as to the advantages and disadvantages of this fuel.
A clean and efficient fuel
Biodiesel derived from tallow is cleaner and more efficient than plant oil due to its higher cetane ignition rating (just as octane ratings indicate petroleum quality). Tallow is also a second-generation biofuel, and its origin from processed meat by-products avoids the use of farmland designated for crops in the ‘food versus fuel debate’.
There are high levels of saturates in tallow which can make it congeal in low temperatures. Tallow diesel cannot meet the required DIN standard for 100% biodiesel (however it can meet this if it is added as a 5% mix with conventional diesel). Tallow availability is also constrained by animal stock rates, which in turn could be affected by climate change.
Removing strain on land and crops
Although tallow as a feedstock is potentially limited, it makes most economic sense for companies with a link to the rendering industry. Importantly, it removes strain on land and crops, and there is scope for mitigating the effects of congealment at low temperatures. In 2010 a 50/50 blend of conventional jet fuel and beef tallow-derived biofuel was successfully trialed by the United States Air Force aboard a C-17 Globemaster III aircraft on all four engines, which proves its reliability as a fuel for the highest operational requirements.