Hmm.. don&#x27;t know why asking a question deserves a downvote.<p>I think you&#x27;re right that it would be more energy efficient -- since a human weighs less than a rack full of goods.<p>But energy, compared to the other costs, is a fairly small component of costs.<p>The bigger question is whether a person is cheaper than a machine.<p>A few years ago before Amazon bought Kiva, they would sell a complete setup for a large warehouse for $15-20m for 1000 robots. This included a lot of setup, but even if we assume it&#x27;s just 20m&#x2F;1000 robots = $20,000 each.<p>So for $20,000 you can get a robot that will work 24&#x2F;7 for a few years. Lets pretend the kiva robots are completely junk after 3 years. That&#x27;s under $7000&#x2F;yr.<p>Obviously, that&#x27;s going to be tough to beat with a human. But for comparison, lets assume a person gets paid federal minimum wage ($7.25&#x2F;hr), there&#x27;s no overhead, no management, healthcare, never gets sick, etc. That equals $15000&#x2F;year. But that&#x27;s only for 40 hours a week x 52 weeks&#x2F;year. So really, we&#x27;ll need 3 people.. so $45000&#x2F;year. (EDIT: I forgot about weekends, which is another 48 hours. So really, we need 4 people, or $60,000&#x2F;year.)<p>Considering that humans are so much more expensive than a kiva robot, the increased energy compared to segways doesn&#x27;t really effect the outcome. It&#x27;s clearly cheaper to use robots and simply pay for the increased energy usage.