The maximum number of turbines that can be placed is ten, which provide a total of 11 units of energy.
However, by simply removing one turbine, there are several arrangements of nine turbines, a couple of which match or exceed the 11 units of energy produced with ten turbines.
Of these, the arrangement that produces the most energy places seven of the nine turbines in windier (blue) areas, but even that can be improved upon. Three turbine footprints can be shifted up to place the remaining two turbines in windier areas.