mifletz,
Not quite sure what you're asking. As for power delivery, a chain drive will have no slippage but there is some friction involved between the chain rollers and sprockets. The power loss do to that small amount of friction is not enough to be concerned with for our purposes therefore you can assume nearly 100% effenciency with chain drive. Compared with a frction drive, roller, which will have varying amounts of slippage depending on many factors such as tightness against the tire, tire tread design and roller design and composition, dry verses wet conditions and several others, the chain drive has its advantages. Friction drive however is comparatively simple in regards to moving parts and installation on a bicycle. I don't know it this answers your question or not. Let us know if we can help you further.
Tom