The turbines have a few interesting design features that are supposed to make the installation and the turbine more economical. The teetering blades and torque limiting gear box are supposed to cut down on fatigue meaning the nacelle doesn't have to be built stonger and heavier which means less steel, which means the tower doesn't have to be built as heavy to support it, which means the concrete pad doesn't have to be built as big. All should save costs in production which flows into price paid for turbines. Earth works are less as well due to smaller concrete pad and being smaller turbines the roads needed to move the turbines to the site don't have to be as big and a single smaller crane can be used to install them. If you believe the brochure this should all combine to make a very cost competitive wind farm dspite not have the output of the bigger turbine farm.
http://www.windflow.co.nz/products