compost heating
good example silage piles. you can make your own with wood chips and grass or straw/hay easily mother earth magazine has good articles about it. can get well over 100 deg C can use it for cooking or hot water.
i’ve seen these shrank down to modules that are less of a fire hazard, even a 55 gal barrel filled with woodchips and compost dirt mixed a 5 gal pail with pee and wood ash and warm water
BioDigester
a larger powerplant could consist of a hybrid car converted into a generator.
might come in handy for running a hottub for free. Have not tested this myself for how it cooks things or smell but some already use such technology for daily living so it must be comparable.
http://www.solarcities.eu/content/how-long-does-it-take-and-how-much-gas-can-you-get
who would be interested in this
restaurants – turn food scraps into refridgerated type dogfood and use the rest like breadscraps and leftover things to make gas. half a 5 gallon pail of scraps should make 1000+ L of gas.
could use a simple water displacement system aswell using 2 barrels or concrete containers. another lady used sandbags on a bag to push the gas out.
https://sciencing.com/compress-methane-gas-liquid-7398367.html not sure how this is stored yet i would really doubt propane bottle would be suited for it using -150 deg c temps and high pressure to make it.
funny way to get poop from cows would be to devise a way to train them somehow or wait untill they fill up with water and startle them somehow ?
