another scenario would be that Siemens et al build multi-billion-dollar facilities but keep complete control of it, without tech transfer or ownership, and thus it's them selling both to Spain and Algeria even if they also pay rent for the desert land;

Yes, that is another possible scenario. Our job as lefties is to make sure that's not the way it turns out.

I do think that Spain has enough solar resource (and a good one at that) to supply itself;

OK, point. I originally used Libya and Italy, but the fact that Libya has oil means that they have access to hard currency to fund the project without building new export infrastructure (ditto for Egypt and the Suez canal), which complicates the argument a little without adding anything substantial to the conclusion.

I am not convinced that the Desertec plans are much more than greenwashing for the companies involved, that is: if realised, it may not grow beyond the scale of a few GW;

I wasn't talking about Desertec specifically - rather, I was thinking a Gazprom-style sovereign utility on the African side and a Ruhrgas-style quasi-sovereign utility on the European side. That seems to have worked out well enough for Russia, and anything that could survive the Yeltsin years is surely a solid design. And solar power - particularly solar power for export via HVDC lines - is an infrastructure business in the same way that natural gas is: You can only sell the power in the places that you have power lines to, and the infrastructure represents a substantial up-front cost.

Unlike gas, however, it does not run out, so if you take good care of your infrastructure, you can keep using it essentially forever. Which in turn means that as soon as it is fully amortised, it makes free electricity in perpetuity (or until Sahara gets a cloud cover or the Earth's axial tilt changes - but in both those cases you'd have to reevaluate your business model for other reasons...).

Sub-Saharan Africa? They have superior resources

Actually, no: they may have a higher angle of the Sun in the sky, but clouds, too.

I was thinking about the Sahara here as well: From a pure production perspective, the smart way to power sub-Saharan Africa would be to start from the south end of Sahara and work your way North. And you'll run out of solar panels long before you reach the border.

- Jake

Friends come and go. Enemies accumulate.

According to your map, Mauritania, Mali, Niger, Chad and Sudan, which are not usually seen as North African countries, are located in the maximum solar potential zone...

"Ce qui vient au monde pour ne rien troubler ne mérite ni égards ni patience." René Char