Free (canine) energy

People like having dogs as pets. Dogs need walking. People don't always have enough time to walk their dog. We need more energy. Inference of this collection of facts: put the dog in a giant hamster wheel and let it exercise itself and generate electricity at the same time. Alternatively a roller-bed could be used. Dogs may need some encouragement to do this electricity generation, perhaps the metaphorical carrot on a stick could be used. Or train it young.