And who the hell wants to climb the thing change the oill grade to a lighter oil in the dead of winter so it does not eat itself alive when the cold wind blows?
I guess we could warm the oil, but that requires debendable electricity...
Actually, they do have immersion heaters in the oil at least the ones in cold climes... On a decent sized wind turbine, the gearbox will take about 80 to 100 gallons of oil and it has to be changed every 6 months to a year. Gearboxes have been a very serious reliability weak link... you might have seen pictures with them on fire. The bearings in the gearboxes are very highly loaded as one would expect to both the radial and thrust loads. Did I mention that these things are a total disaster?