Engineering Economics question - this is not a trival question and requires gathering some data and doing some back of the envelop estimation. It has an actual number value, maybe not a practical number but a number none the less.Suppose you were an engineer that had the viewpoint that killing stray dogs was deplorable. Your goal was to find mechanical work for dogs in a hampster type running wheel connected to a generator to produce either electrochemical products like hydrogen/oxygen or sell the electricity back to the power grid.How high would the price of electricity or hydrogen/oxygen gas have to be in order to cover the costs related to the dog?For the purpose of the model, the dog has been trained to run in order to recieve a meal packet, the dogs size is 30 pounds, and the only costs related to the dog are the food, which is 1 dollar a day (adjust for inflation from there).Please pass this question along to your Engineering Economics professor for consideration

Aside from the moral fact that you would be enslaving the dogs, I would think that the amount of CO2 and methane the dogs generate would counteract any eco-friendly ambitions you have. Then there is the amount of energy required to feed, water, and maintain the dogs. You would also have to factor in the amount of energy required to construct the generating equipment and facilities. I doubt that a dog could generate that much energy over it's lifetime.Again I look at your problem from an energy standpoint, not an economical one.Very interesting question though. I'm giving it a star.JeffM