Original URL: http://www.theregister.co.uk/2010/06/22/sahara_sun_power_cobblers/

Big EU imports of Sahara sun-power coming soon?

Headlines to which the answer is no

By Lewis Page

Posted in Science, 22nd June 2010 15:18 GMT

The European Union might subsidise "interconnector" undersea power lines beneath the Mediterranean for the purpose of importing solar energy from the Sahara desert, according to reports.

"I think some models starting in the next 5 years will bring some hundreds of megawatts to the European market," European Energy Commissioner Guenther Oettinger told Reuters on Sunday, following a meeting with energy ministers from Algeria, Morocco and Tunisia.

A few hundred megawatts is insignificant against European energy demand, but reportedly the EU intends to back the mighty multidecade €400bn Desertec scheme, which will see such efforts scale up into the gigawatt range.

Oettinger views the idea as a fair deal between Europe and North Africa, in which the wealthy nations north of the Mediterranean get energy and the desert nations get massive investment, jobs and knowhow.

"Renewables are a two-way partnership because electricity produced here is for the home market of north African countries," he told Reuters.

"Maybe a bigger percentage of the electricity will be exported to Europe but at the same time we have to export the technology, tools, machines, experts, and so it's a real partnership, not only a partnership by selling and by buying."

Solar power plants' performance worsens severely the further north of the Equator they are situated, owing to the increased slant at which the sunlight strikes the atmosphere and the surface beneath. The cloudier skies of the higher latitudes add a further negative effect.

This means that a given solar plant delivers hugely more power if it is placed in the Sahara than it could in Europe, and most analysts believe that this more than offsets the added cost of power lines to carry the juice north. Thus North African solar is a very commonly-advocated green energy plan - so much so that it is common to read statements such as: "If just 1 per cent of the Sahara Desert were covered in concentrating solar panels it would create enough energy to power the entire world. That's a powerful number ..."

Powerful yes, but actually complete rubbish*, as well as being meaningless. The limiting factors on Saharan sun power are not area but cost and the attitude/capability of governments in the area.

However, nothing of any real note - nothing to compare with existing European fossil-fuel imports from North Africa, for instance - is yet on the cards. Reuters reports that the various industrial titans participating in Desertec have yet to present their plans to Brussels. They are expected to demand subsidies as a condition of proceeding, but these may or may not be forthcoming in sufficient quantity.

Green groups have reportedly voiced concerns that the interconnector lines might actually be used to sell cheap, dirty fossil power to Europe under the pretence that it was green.

"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.