Hydrostatic transmissions work fairly well when the pump and the hydraulic motor are in close enough proximity to be in the same housing. Putting them 130m apart requires 260m of tubing, which adds some friction loss, which gets worse with falling temperature.
Allowing the wind turbine to swivel nominally requires addition of a dual channel rotary hydraulic coupling, or a sturdy right angle gearbox.
I said the coupling is 'nominally' required, and it is if one requires unlimited yaw rotation. ... but I heard of a smaller wind turbine that was allowed to swivel on its own, and never yawed much more than one full rotation. The electric cables just dangled down the interior of the tower. The original mercury slipring was removed after the mercury froze.
Doing the same thing with two hydraulic tubes seems possible, but would require hydraulic fittings that don't leak when the tube is tweaked a little. That might require a little development money...
Mike Halloran
Pembroke Pines, FL, USA