The left over glycerine can be used to produce biogase, methane. This is being done in Sweden in reasonable scale.

The same goes for press cake from rapeseed oil production and leftovers from ethanol fermentation that is not needed as cattle feed. The only (so far) large scale ethanol plant in Sweden has been complemented by a biogas plant that uses chaff from the wheat before grinding and sludge after distillation for methane production.

"how much could waste products (food waste, sewage, yard debris, agricultural byproducts etc) offset current energy needs?"

That's why they're calling them BB's.. and I suspect they will be more highly 'respected BB's' as Our Daddy's ol' BunkerBusters get less and less reliable. As I'd say to Boof's initial remark upthread, anybody who is brewing up BioDiesel these days is likely NOT an advocate of keeping 800 million vehicles running, and that a major (implicit) aspect of their plan includes restructuring to vastly reduce our ICE dependency.

Bob Fiske

In your best estimate, as I imagine you have already thought this out, how much could waste products (food waste, sewage, yard debris, agricultural byproducts etc) offset current energy needs?

I did a calculation like this in my thesis. If I recall correctly, I think the gross was enough to replace our current liquid fossil fuel usage. But the net is the problem. The EROEI is currently not good enough. At present, it probably makes the most sense to burn the waste to produce electricity, but that poses problems of its own.

Still have the footage from the Ethanol plant, just procrastinating on making something professional to go with it.

Someone e-mailed me yesterday asking some specific questions about energy usage in sugarcane ethanol plants, and I told them you might be able to get them in touch with someone.

My knowledge of the U.S today is dated - the number of places that use frying oil is undoubtedly much, much higher than 1988, while the use of beef fat in such places has likely declined by a very significant percent.

One reason Valley Proteins collected such used oil was the large poultry industry in the region, both the turkey producers in Rockingham County, VA, and the chicken industry in Maryland and on the Delmarva Penisula - the protein shuttles back and forth, so to speak - animals feed on the 'leftovers,' then in turn, when they become leftovers, they are fed to the next generation. Since DC still had (has?) something of a regional meat industry, it was a profitable cycle for all concerned.

What is interesting is recognizing the limits to this cycle - though fossil fuels can be at least theoretically eliminated from the entire chain, the amounts produced within the entire chain are very dependent on fossil fuels. If 20% of the available biomass can be converted to fuel required to supply the system for example, then the math may may seem reasonable, until you cut the total amount available for conversion by something reasonable, say 33% due to any number of conditions, from climate change to economic dislocation. At that point, you have roughly half of what exists today in terms of actual material - a BB, but a pretty small one, and then, only in the sense of doing things in a more constrained manner, which isn't growth, though it may be acceptable to the alternatives.

The feedstock, so to speak, will be contracting as yields in fields decrease, as food is diverted from animals for human consumption as either fuel for the machines or fuel for humans - and yes, I am certain there are people who know how to calculate such numbers, and have done so - a few are considered doomers, others are just planners looking at different scenarios.

In no sense do I wish to disparage such efforts, it is just merely that the likely end result will be much less than currently anticipated - some of the changes coming to the U.S. will include some no longer possible to avoid decisions - what is America's current lifestyle worth? A lot of interests will conflict, and the wisdom which seems to have been missing since the early 1980s will be in sore need.

But in terms of NYC, there was an interesting idea floating around Germany in the mid-1990s (may have heard it best presented on the radio - the Karlsruhe Forschungszentrum has a weekly program on a local non-commercial station, where a lot of research is discussed).

At that point, Germany's mandatory recycling laws had taken effect, and the country was literally (litterally?) drowning in used paper - the price per ton sank to negative levels, basically, as you had to pay to haul it away (this also had the effect of destroying a generations old trade in France of collecting old paper). At that point, one researcher seriously suggested simply burning the paper instead of recycling it. His points were interesting - since many German cities already have incinerators that produce electricity, there was no need for additional infrastructure, the paper was essentially a CO2 neutral fuel, the truck exhaust and fuel use in shuffling paper around was not trivial, plus at that time, paper processing required some fairly nasty chemicals (also changed over the past years here - a number of problems require a number of solutions, and there may be more than one solution to any given within a set of interlocking boundaries - the complexity argument is not wrong, it is merely that standing around for a generation is not exactly the same as noting increasing complexity is a trap - learn and adapt are what living organisms do, if they wish to remain alive into the future.)

As can be imagined, the idea of burning all the waste paper which flows like the tide into a German city was just a touch too radical to be accepted - burning it seems like such a wasteful thing, but his numbers were quite well worked, and quite convincing - it would be possible to actually generate a decent percentage of electrical power using biofuels, so to speak, without any extreme changes to anybody's current lifestyle (the streetcars and intercity rail network are electric, after all) while in addition reducing the amount of exhaust created and fuel burned in used paper transport - the incinerators are generally much cleaner than a 12 year old diesel truck.

Sometimes, truly ecological thinking doesn't really match up with the image of green living which many people have. Of course, growth would not really be possible with the paper as fuel idea - living within limits is likely another reason it was not so readily accepted, after all.

Any bio-solution will have this feature - and then we see how much smarter we are than yeast.

Roger, I like how you think. And thanks for the link to DE!

I agree on Byproduct vs Waste but when "rolling" the byproduct into a closed loop Ethics (read The Jungle about how they made sausages back in the day) and Science (EROEI, also think of the mistakes we've made with animal feeds propagating Prion Diseases) need to be in the decision process.
matt