I've got a mix of evergreen and deciduous 30+ meter trees on my lot that produce (eyeballed) about 25% roof shade in winter and about 50% roof shade in summer. For aesthetic reasons, the trees are non-negotiable: they stay (and neighbors' trees provide morning and evening shade; equally non-negotiable). It appears that kills the deal; the linked PDF says my region could expect about $60 worth of power a month without the trees, but with them I'm guessing it would be at best $40 a month, which isn't going to cover a 5% interest cost.
