> And it seems obvious that a mishmash of solar panels on thousands of roofs pointed in random directions, is nowhere as efficient as a large solar farm. I don

> And it seems obvious that a mishmash of solar panels on thousands of roofs pointed in random directions, is nowhere as efficient as a large solar farm. I don't think that's obvious at all. Solar farms either use up expensive land, or have to be located so far away that transmission costs could be a significant percentage. Solar roofs get both land and structural support for free, thye're located much closer to where the electricity is needed, and can be engineered to double as a roof surface that you needed anyway. They also aren't "pointed in random directions": installers carefully analyze each roof to determine what sides/angles are worth putting panels on. > A rational system generates the power it needs on the grid that needs it when its needed. Solar fundamentally can't always generate the power when it's needed, regardless of where you put the solar panels. That said, solar does a particularly good job of powering air conditioning loads: for that solar roofs both put the power where it's needed, and when it's needed.