Complementary can make many things. You usually need long-distance transmission for wind power - in Texas the good wind is in the panhandle, well away from urba

Complementary can make many things. You usually need long-distance transmission for wind power - in Texas the good wind is in the panhandle, well away from urban areas. Rooftop solar is usually right where the power is used -- urban areas. So if you have limited and slowly-growing long-distance transmission, rooftop solar is a way to get more renewables into the same grid. That's one kind of complementary.