When I look in the tech tree in game to research upgraded wind turbines, they all start with 'Unknown key:"technology-name.wind-turbine" X' where X is which tier of wind turbine I'm researching.
If I had to guess, it's probably just a typo somewhere.
As far as I can tell, the mod functions fine except for this issue.

To Dost, if you still care to fix this mod, or to anyone bothered enough by this --
Simple number suffixes in tech name keys like you have set up here (wind-turbine-2) get truncated and dynamically replaced in init.

In other words, the game sees your technologies keyed "wind-turbine-2" through "wind-turbine-7", and is looking for a singular "wind-turbine" locale entry to make into <NAME> 2-7 on its own. Thus failing, because you're defining them manually.
(A bit of a failing on the devs' part, as this ought to fall back, but nonetheless...)
The fix can be done two ways, both very simple -- changing the keys to not trigger that mechanism, or just defining a singular wind-turbine locale entry for the techs.