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Monday, December 14, 2009


Ben Prentice


While biodiesel is a reasonable start it is really not a very environmentally friendly solution overall. There is a beter-for-the-environment and more cost-effective for Marriott solution: the Vegawatt (www.vegawatt.com) cogeneration (CHP) system that uses your waste vegetable oil to create electricity and hot water right on-site for your properties, and the ROI is typically only 2-4 years.

FYI: Bio-diesel production utilizes Methanol (a petroleum product) and Lye (Sodium
Hydroxide, a hazardous caustic agent) to convert vegetable oil into a fuel similar
to diesel fuel. Up to 25% of a bio-diesel batch is converted to glycerine. While
glycerine is a common food sweetener, the glycerine produced from the biodiesel
process is contaminated with methanol and lye, and must be disposed of as a
hazardous waste, usually by burning.

Transportation of WVO for industrial production of bio-diesel is extensive and
expensive. Any oil traveling to a rendering plant may have already seen several hundred highway
miles and several middlemen before arriving for processing. This transportation
adds a significant amount to the oil’s (and thus your property's) overall carbon footprint, and should be included in any calculation of the oil’s original use cost.

After rendering, some oils are sold to bio-diesel producers, loaded back onto a
class 8 truck, averaging 4 miles per gallon of diesel fuel, and shipped to the
biodiesel plant where they undergo transesterfication into biodiesel. Additional
energy, along with large amounts of process chemicals are utilized to convert the
commodity oil into biodiesel. Glycerine, the waste product of the process, is
usually burned on-site contributing only combustion emissions to the air.

Once the bio-diesel is produced, it is loaded back onto a class 8 truck, again
burning diesel at a rate of 4 mpg, for transportation to wholesalers, who dilute
the biodiesel with petroleum diesel and then transport the fuel to retail stations.
The Rating system of B5, B10 and B20 represents the percent of biodiesel in the
blend, (5%, 10% and 20% respectively). Once the fuel finds its way into a vehicle’s
fuel tank, it is utilized in an engine that can only obtain 30 - 35% efficiency.

On the other hand-transportation of fuel for a Vegawatt system involves a kitchen worker and a
shortening shuttle or stock pot. The energy efficiency of a Vegawatt system is over 70%. The amount of energy embedded in transporting oil for a Vegawatt is less than that contained in
one French fry. There are no liquid wastes. Any solid food particles suspended in
the oil are caught in filters which at their end of life can be disposed of in an
ordinary dumpster.

To summarize total cycle costs, biodiesel has high transportation costs, high
embedded energy costs, a high carbon footprint, a reliance on petroleum as a
necessary process chemical, and a low end-use efficiency. In stark contrast, the
Vegawatt has zero embedded transportation cost, zero process chemicals and a
very high end-use efficiency.

Gary Lueck


Until a nation-wide supplier can be found, there are organizations in many of our large cities who are looking for dependable sources of used fryer oil to use as bio diesel. Craigslist is a great way to connect with them.


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