why do the moderns use three blades and old school use four?
The literature indicates lower costs and greater efficiency in three blade turbines. There are also comparative studies on two vs three blade turbines.
On the question of damage to wildlife/environment, I searched for best practices in wind turbines and came up with several documents worth looking at; of course ideas are one thing and implementation is another, but still...
Best Practices for Sustainable Wind Energy Development in the Great Lakes Region - GLC.org (2011)
Obviously not completely current, but nice case studies and relevant policy questions raised.
GP Wind - Good Practice Guide - EU Support from Intelligent Energy Europe
General framework and policy guidance, and some interesting details.
IEA Recommended Practices - IEA Wind.org
"The IEA Wind TCP is a vehicle for member countries to exchange information on the planning and execution of national, large-scale wind system projects and to undertake co-operative research and development projects called Tasks or Annexes. As a final result of research carried out in the IEA Wind TCP Tasks, Recommended Practices, Best Practices, or Expert Group Reports may be issued. A Recommended Practices document includes actions and procedures recommended by the experts involved in the research project. Use of these documents is completely voluntary. However, these documents are often adopted in part or in total by other standards-making bodies."
You can view the Recommended Practices library by clicking here."
There are quite a few special reports that address noise and other environmental impacts.
I was peripherally involved with some of the research around the Cape Wind project in the early 2000s. Planning began around 2001 and the project leases were terminated in 2017. It's also a great case study - you can learn more from failure than from success sometimes.
Cape Wind - Wikipedia
(a fairly detailed summary - there is plenty of other coverage on this too).
"The Cape Wind Project was a proposed offshore wind farm on Horseshoe Shoal in Nantucket Sound off Cape Cod, Massachusetts, United States. It was approved, but then lost several key contracts and suffered from several licensing and legislative setbacks. The developer, Jim Gordon of Energy Management, Inc. eventually terminated the lease rights for the site in late 2017..."
The spectacle is not a collection of images, but a social relation among people, mediated by images. - Guy Debord