Big EU imports of Sahara sun-power coming soon?

"This is a good question but not a question to destroy our project," Oettinger said. "This question must be answered by a good answer and so we need ways to ensure that our import of electricity is from renewables."

Perhaps indicating the scale of the difficulties the Desertec project faces, Oettinger reportedly considers that technological monitoring would be required to enforce green compliance by North African electricity suppliers. ®

*Bootnote

A sunbeam falling vertically onto the Earth carries one kilowatt of power per square metre. At equinox midday on the Equator itself this actually happens, but half the time it is night and for almost all of the day the sun is rising or setting rather than straight overhead. Then, there are clouds sometimes even in the Sahara.

Thus a square metre of ground in North Africa receives about 0.25 kilowatts of sunlight on average. "Concentrating solar panels" are projected by their inventors to offer energy efficiencies of 6.8 per cent, so they would yield 148 kilowatt-hours per square metre of panel annually. Over a large area a substantial proportion of the surface would actually be required for access, so the yield would be 74 kWh per year per square metre at best.

The Sahara desert has an area of 9.1 x 10¹² square metres, so covering it all in such panel farms would yield around 673 petawatt-hours each year.

Current global energy demand is in the range of 140 PWh annually and thus would require at least a fifth of the Sahara (before we even consider the issues of a global interconnector grid, Saharan night time etc).

One also notes that if all the world's present population used energy at the same rate as Americans do today (or if the population doubled and used merely European amounts of juice) this would rise to most or all of the Sahara - which means around 6 per cent of the entire land area of the planet covered in extremely expensive equipment. This would be a very wealthy future human race indeed.