[tobtoh]

Don't quote me on this, but I recall reading that there is a layer of air at ground level that is very turbulent/choppy due to it's interaction with the ground which makes it terrible for wind power generation.

[Pxtl]

What the parent-post means is that the machinery of the generator is positioned at the bottom below the blades instead at the top of a tall column behind the blades. Presumably this creates some savings in terms of construction and maintenance.

[bigfudge]

perhaps also aerodynamics relative to a big generator blob right at the top?

[lippel82]

Only the generator is at the bottom, the power still comes from the upper part of the structure and is transferred mechanically, I would assume.

[throwaway316943]

VAWTs do ok in turbulent conditions. HAWTs don’t like it because they need a consistent stream of air flowing in one direction.

[8note]

General fluid speed is ~0 at any surface and has some gradient to the proper wind speed as you get some distance away from the surface.