Energy
Wheeling
Wheeling is transporting electricity across a network that belongs to somebody else, from the point it is generated to the point it is consumed. The network owner charges a wheeling charge for the service, and losses on the way are accounted for separately.
For a site selling to a distant buyer, wheeling charges and losses come straight off the delivered price, so they belong in the model from the start.
They are set by the state regulator and they change, which is why a long contract usually says who carries the risk if they move.