A wind spill would be a hurricane or storm, a solar spill would be a major solar flare.
Much less prosaic, I’m afraid:
A wind spill would be rare birds cut up by the blades as they pass straight through them on their migration. We deliberately put windmills in bird paths because we, and the birds, both want to take advantage of the wind energy. My sister used to consult on a wind farm in Egypt that had this exact problem but the migratory path was used by an endangered bird species so they couldn’t just ignore it.
A solar spill is a bird flash-roasted as it passes through the light of a gather-reflector system. Mind you, we don’t build many of those for some reason.