Equatorial climates tend to be suboptimal because they involve lots of rain and cloud cover. Desert climates like the Sahara are ideal, and not just because of their proximity to Europe. Transmission costs need not be excessive once economies of scale are achieved.  The Sahara isn't much good for anything else. It could be a very good export and foreign currency earner for Saharan countries were it not for political instability threatening installations and transmission lines. Failing that, southern Spain would be the ideal locations were it not for a lack of political imagination.

Note, however, that production tends to peak around midday which might limit power availability at other times.  Ideally an east west middle eastern and north African grid spanning form Saudi to Morocco would provide power throughout most of European daylight (and peak demand) hours. In the longer term, a global grid extending all the way to Mexico could provide power throughout northern hemisphere daily demand cycles and valuable revenue and employment for more southern countries. (In return, northern installations could provide wind power for more southern countries at night or in winter).

Index of Frank's Diaries