I couldn't help but notice your reference to McNasty French frie(r) oil as the source of biodiesel fuel for McDonald's lorries in the UK.

Do companies such as McDonald's employ energy economists? McNasty French frie(r) oil as delivered from the frying tub is filled with solid materials, water, and very nasty long chain molecules of organic molecules derived from the chemical reactions between the oil and those savory and unsavory items which have been dropped into it during its 'use' cycle.

This garbage laden oil when exhausted to the point where it gives the potatoes a distasteful flavor, which can no longer be disguised even by salt and vinegar is know discarded and the pot, perhaps, scrubbed with more chemicals before it is refilled with more 'cooking' oil.

The garbage laden oil cannot, I say cannot, be used directly in McDonald's lorries-if it were it would clog the fuel lines and the contained water could irreparably damage even the sturdy diesel engines.

Therefore the garbage laded oil must be processed by an expensive facility to remove solids, water, and high molecular weight residues.

What is the true cost of 'biodiesel' fuel after it has been accumulated, transported, filtered, chemically processed, containerized, and returned to a fuel distributing station? I would guess that McDonald's could burn alcoholic beverages more cheaply than biodiesel and that might help the post-game atmosphere at a UK soccer match more than burring McGarbage can ever do.

Of course McDonald's could simply pump oil out of the ground, further depleting global supplies, process the oil in a refinery and then have it transported to a station so they could fuel up. So are you so convinced that biodiesel isn't worth the effort or are you afraid it might hurt oil jobs in the North Atlantic?

Interestingly, using waste vegetable oil, or WVO, to produce biodiesel is profitable, however there are more profitable things that can be produced with them, which leaves the supply available for fuel short. McDonald's only anticipated losing money in the short term and at pennies on the litre. Recycling WVOs is not a hugely expensive or complicated proposition - it requires facilites like any refining I imagine, but creating biodiesel from WVO is something people manage to do in their homes. As for actual cost of biodiesel, the DOE and USDA did a study some years back assessing various production costs to come up with comparative energy yields to begin to answer this very question. The soybean based biodiesel they looked at had at energy yield of like .84 vs. petroleum's of around .81. Now soybean oil yield isn't high, and that number is from field to fuel. The used fry oil of rapeseed (and sunflower?) is recycled first, and also from much higher yield crops, which has to positively increase the energy yield we're talking about. Bioethanol had a yield of like 1.84, so I think the alcoholic beverages remain the more expensive choice - also providing less energy gallon to gallon.

There are real issues with biodiesel, like nitrogen oxide emissions, what to do with the glycerol, enviornmental impact of devoting agricultural resources to this - but you haven't hit on any of them here. So perhaps the point was to hate on McDs a little, and that's all well and good, but their oil recycling plan is just good business sense - for all the reasons reflected on in the article. It costs some at the outset with great advertising and PR return, and it's expected not to cost them any additional over time. They're even talking about a possibility of being able to sell a bit of their own biodiesel - aren't you just waiting to line up for McFuel?

that should be 1.34 on the bioenthanol yield, not 1.84 :)