The phrase "hub height" refers to the height of a wind turbine's hub, which is the central part where the blades are attached. It is the distance from the ground to the middle point of the turbine. Full definition
The study focuses on the market value of wind and total system costs arising from different combinations of wind turbine hub height and specific power. (community.ieawind.org)
Palmas Altas will feature 46 Nordex AW125 / 3150 turbines with hub heights of 87.5 metres and 125 - metre rotor diameters. (renews.biz)
Source: Adapted from NREL's 110 meter hub height wind speed map for areas achieving 35 % capacity factors or greater (November, 2014). (blog.cleanenergy.org)