Inspired by the "Improved Horse Drawn Carriage". I like the idea of animals going out and harvesting grass and other natural vegetation for energy. And when I say collecting energy, it could be in the form of food for humans, raw material for thermal depolymerization, etc. Converting mechanical energy to electrical is fine, but I don't see how that could be accomplished without severely cramping the lifestyle of the animals.
This is kind of like the open range model of cattle ranching, or hunting wild animals. But cattle ranching doesn't work too well in some environments, and hunting is inefficient and objectionable to many.
Lets think about deer. They live and forage over a wide area. Some number of them end up dying in the wild and feeding the scavengers and predators. While that's fine, us humans are the TOP predators who aren't to proud to scavenge as well, so I have no problem letting other scavengers and predators play a somewhat reduced role.
So we just need to make a device that attaches to each dear and tracks its location and health. When one starts to get old, rather than let it die in the woods, the device would make scary sounds in a directional nature to herd the animal to an appropriate location where is can be collected. If the deer population is growing too fast for an area to support, younger ones could be herded and collected as well. Obviously pregnant females would need to be directed to an appropriate location as well so the newborn fawns could be tagged.
This might be applied to other kinds of animals as well, but the tracking devices would be easier to build and more cost effective for the larger animals. The intention is to allow the animals to lead basically a normal life, but then insert humans approximately at the point where the animal might otherwise be killed by a natural predator or would die and be consumed by scavengers. This also allows control of the population to avoid having too many for the available resources in the winter.
There is plenty of room for innovation in tagging methods using drones etc. to make this more efficient.-- scad mientist, Jan 26 2016random, halfbakery