Robots really are nuclear powered
With the new hype about fuel cell, etc ways to power our robots in the future, it should be known that even the "ghetto" batteries currently on robots are high-tech.
Robots are nuclear powered
When a battery runs out, what do you do? Recharge it
And what do you recharge it with? Electricity (120V, 60 Hz to be exact)
And where does that electricity come from? Electric Power Plants
Since most of the regionals are in or near big cities (reasonably sized cities), and most of the big cities are powered by nuclear energy, and that power goes into your robot (at least when you recharge your batteries), the energy comes from nuclear fission.
Therefore, the mechanical work of hanging, moving, and grabbing and manipulating balls comes from nuclear energy. Isn't that cool. No fossil fuels were ever burned and no carbon dioxide was ever released to provide energy for your robot.
Disclaimer: If all your batteries were charged at home, the above claim cannot be guaranteed. In addition, some areas of big cities are still powered by fossil fuels (or other clean energy such as hydroelectric power, solar,etc...). Additionally, fossil fuels are used in the production of steel (Aluminum, however, is mostly an electrical process).