If solar is 20% efficient at turning solar energy into power, we’d only need to cover a land area about the size of Spain to power the entire Earth renewably in 2030.  If that area were broken up into pieces and distributed around the world the “footprints” would be small.  The map below shows an example of the distribution (although a much large number of smaller sites are likely).  How much of the earth’s surface wiould be needed by 2030?  Just over 0.00001%, or approximately 1 acre out of every million.