How much time is lost due to rain, clouds, snow, nights and of course winter sun when it is low on the horizon?
Who get to wipe the dust off and how many feet of snow per year will need to be cleaned off?
10-15% productivity????
NYC gets about 4kwh/m2/day for a tilt=latitude photovoltaic collector. These collectors are flat. NYC is about 41N.
http://www.nrel.gov/gis/images/map_pv_national_lo-res.jpg
