The Stinkiest Fuel on Earth

What about human "poop"? Our poop could contribute as well as we outnumber by a very huge margin all of those animals that you have specified. =)

I am almost a hundred percent sure that is how they ran Barter Town in Mad Max: Beyond Thunderdome

I think the same problems exist as with corn ethanol, we are already have a shortage of arable land and good soils. Using animal waste as fuel instead of fertilizer will deplete soil nutrients and drive up the cost of manure which will have the effect of driving up already high food costs. Using human waste from sewage would be better indeed as it is mostly dumped directly or indirectly into the oceans.

When the bacteria are done digesting the manure/organic matter there is a residue or bi-product that is superb for use in fertilizing arable land. If the digester has been fed manure, one of the bi-products is a nitrogen rich liquid that can be pumped onto fields easily.

I wonder then do you collect the methane at home for someone to pick up? What are you going to do with the methane at home? Does it make enough to be used in some sort of methane fired generator, or maybe it could be used for home heating?

I think this an interesting chemistry trick, but it doesn't seem like the efficiencies would ever be high enough to justify the costs. If you can create them on a larger scale such as at a sewage treatment plant where you are getting thousands of cubic feet a day or at a large waste collection facility then it might be more useful. I'm not going to follow my dog around and collect his waste for a measly .2 kilowatts worth of power and buy a methane collection unit to do it. I'll by a small windmill for less than a thousand dollars and be done with it.

Why is it that the chicken produces more methane per pound, but the dog produces more kilowatts per pound?

I would have thought that the methane from each waste product would have the same amount of energy in it?

And, as far as fertilizer goes, we already use too much of it, which is why we have such a large dead zone in the Gulf of Mexico. Better to take the manure off the farm to make methane and stop growing fertilizer-hungry corn for ethanol.

If you take the manure of the farm then you use gasoline, if you use one gallon of gasoline to transport 200 pounds of elephant dung then you would basically break even.

Another difficulty is that if you produce 230 cubic feet of methane it is produced at atmospheric pressure. Unless you are going to transport it in a giant balloon then you have to compress it, another energy loss.

Shouldn't that be 39 kilowatt-hours (kWh)? Kilowatt is how much POWER you are using at a given moment in time. Kilowatt-hour is a measure of how much energy you have used. 2 kilowatt heater uses 48kWh running for 24 hours.

lnwolf41 This idea looks good in a study but what are the cost to feed the animal, man hours to collect the crap, ensure process is working collecting the gas and processing the gas for use.
simple answers to transport and processing, use methane
to run compressor and vehical.
Also one other concideration is how much land area will
you need to do all this? Most housing developments have small backyards, unless they do a co-op system.

the biogas from the poop was produced in an enclosed tank,bioreactor.Bio-methanation (an aerobic process of organic materials decomposition) occurs in there which then produced carbon dioxide n methane as the final product of the biochemical process. This renewable source of energy had been used in ages by the rural indian comity.

How much electricity can be generated from a cubic feet of methane?

This is not a new idea at all. The World Health Organization reported on a study of biodigesters for use in "Third World" countries in the early 1950's. The low-tech biodigester solution resolved 3 problems in those countries: no waste treatment systems; scarce fuel supplies; and a source for relatively safe fertilizer.

The biodigester turns all manner of organic matter into fertilizer, while producing methane for fuel. And a carbon filter in the methane gas line would remove "the stink."

Yes, poop and for that matter any reasonably biodegradable organic matter is a feasible energy system, at least for cooking and heating, even at the household scale. My 9 yr-old septic tank at home collects methane and pipes it to a stove. The gas given of by our poop is enough to cook a meal's worth of rice for the household everyday.

Sometimes I also put in rubbish and yard wastes to enhance gas production.

The septic tank is of ferrocement and is actually cheaper by half to build than conventional reinf concrete tanks.

I also believe existing rectangular septic tanks can be hacked at little cost to collect the gas.

The 'downside' is only blackwater can go into our septic tank, as greywater will dilute the mixture. Our graywater instead goes into infiltration trenches of their own.

bojig, philippines

So what's new? Have seen it since childhood back in India. Remember a house in a village have their lighting/cooking done by 'Gobar (dung) gas'.

I think you mean Kilowatt Hours. Kilowatt is an instantaneous measurement. You cannot purchase ten Kilowatts of power.