it does seem to me that this is a good use of tallow, if you
must have it.
The biodiesel trips seems to work best with
wastes. I don't think it's quite as good with virgin oils, but it's quite good with material that is otherwise waste. I think biodiesel has a lot to recommend it.
I believe that with oil better than $70/barrel, biodiesel
is competitive, even with virgin rapeseed. So one doesn't necessarily need sheep for it, but one does need water with which to grow the rapeseed.
I recently referenced a review article from
Chemical Reviews here,
http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=115x59526 that gives some idea about what we in the US could do with our yellow grease. Here's an excerpt:
A number of waste triglycerides are available including yellow greases (waste restaurant oil) and trap grease (which is collected at wastewater treatment plants).37 Yellow grease is used in the manufacturing of animal feed and tallow, although concerns about mad cow disease are limiting its usage as an animal feed. Trap grease has a zero or negative feedstock cost but is contaminated with sewage components.37 A recent study of 30 metropolitan areas in the U.S. indicated that the U.S. produces 4.0-6.0 kg/(year-person) of yellow and trap grease, respectively.37 ultiplying this number by the population of the U.S. indicates the potential production of biodiesel of 1.3 billion and 1.9 billion L/year from yellow and trap grease, respectively.33 The U.S. consumed 160 billion L of diesel fuel in 2003 in the transportation sector;9 therefore, biodiesel derived from yellow and trap grease could only supply up to 2% of the annual diesel fuel consumption in the U.S. However, trap grease must be disposed of, and converting it into biodiesel would be an efficient way of using an inexpensive waste material...
...The feedstock costs decrease from canola oil > soy > tallow and lard > yellow grease > trap greases...
I have just text searched the article to see how such a business might apply to large native deposits of sheep, but unfortunately
sheep aren't mentioned. But tallow itself seems to be cheaper than rapeseed (canola), and at current prices, at least until
demand rises, canola oil is competitive.