Originally Posted by imageWIS
Huh? How long is an 18-wheeler? I mean, on top of the entire cab there should be enough room for enough panels to AT LEAST power the electrical systems and the A/C.
The cab is just the front part. The trailer usually doesn't belong to the trucker.
They could make panels with magnetic bases and stick them on every trailer they pick up, but that would require facilities, training, storage, etc. For most operations, it would probably be inefficient enough not to justify the cost.
The cost of the development, manufacture, marketing, facilities, maintenance, training, etc. that would have to go into the project most likely doesn't beat the cost of the minimal extra fuel to run the electrics or whatever the power can be used for.