Perhaps this is a silly question, but do we have any information on available roof space across the United States? I'd be interested to see what kind of power o

Perhaps this is a silly question, but do we have any information on available roof space across the United States? I'd be interested to see what kind of power output could be produced if we were able to add solar panels to a large majority of the nation's buildings. Though I suspect that kind of distribution would significantly increase costs for duplicate components and may fall victim to low efficiency transfers into the grid. Afraid I don't know enough about how today's systems operate.