As I see it, we have three variables:

• Inclination (the straighter the sun hits the athmosphere, the more penetrates - thus more radiation hitting your skin closer to the equator)
  
• Clouds (more sunny days gives more output)
  
• Transmission

I think the main factor would be that of placing it in a desert, that is a place with little or no clouds. The difference in inclination is not that great and HDVC is very good. Then again I do not know how much cloud you would have to put up with at the best sites in Greece, Spain and Portugal (abbreviation GSP?).

Sweden's finest (and perhaps only) collaborative, leftist e-newspaper Synapze.se

It depends heavily on Morocco, doesn't it? Via Algeria to the Mahgreb, via Spanish Sahara to the Trans-Sahel, over the Strait to Spain.

Given either Algeria or Libya, Tunisia to the Italian peninsula via Sicily is also straightforward.

I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.