Has anyone thought of putting medium size wind turbines on electricity pylons?

Obvious advantages:

- the most expensive bit is already there

- objections to the tower being there can’t be raised

- the wiring could presumably be easily be modified to move the electricity.

Disadvantage:

- could only carry medium sized turbines because of the strength of the towers and the need for the blades to clear the wires.

I would love to work out a bit of the economics, but I can’t quickly find on the web how many pylons there are in the UK.