"Once the foundation is in the ground" is of course the big thing, as each foundation is unique (even if they all look the same they are specced to exactly the

"Once the foundation is in the ground" is of course the big thing, as each foundation is unique (even if they all look the same they are specced to exactly the water depth and local spil conditions), and a lot of the installation risks are in the foundation. Rock may be harder than expected, or there might be a boulder hiding in the sandy soil. After the foundations are in, the installation of the tower, nacelle and blades is repetitive work. There should be little variance between sites left then. Weather is probably the most significant differtiating factor left.