More energy falls on the world's deserts than the entire world consumes in a year. Gather some of the energy falling onto the 9 million square kilometers (3.5 million square miles) of the Sahara, and you could power large chunks of the globe.
That's the thinking behind Desertec, a plan to build massive solar thermal plants in the Sahara desert to bring electricity to Europe, the Middle East and North Africa. A dozen finance and industrial firms have lined up to support the plan, which is expected to be complete in 2050.
The benefits of Desretec are plenty. It would meet 15% of Europe's power needs with clean electricity. It would help European countries achieve their goal of reducing greenhouse gas emissions to 80% of their 1990 level by 2050. It would bring electric power -- and jobs -- to resource-poor areas of northern Africa and the Middle East.
But Desertec has a few pitfalls too. It will use Concentrated Solar Power (CSP) technology, which involves mirrors that focus the sun's rays onto tubes carrying water. The sun's heat boils the water, and the resulting steam drives turbines that generate electricity. It takes large amounts of water to keep the tubes filled and mirrors clean. And water is a resource the desert, by definition, doesn't have much of.
There's also the need for a great deal of cooperation between the governments of the countries included in Desertec's span. These Maghreb nations -- Algeria, Libya, Mauritania, Morocco, Tunisia and Western Sahara (which is claimed by Morocco) -- have their own laws about foreign investment and a record of missed opportunities to integrate their economies.
Policing such a monumental installation would present another challenge. And who knows whether in 40 years technology will have left CSP behind. With prices of photovoltaic cells falling, localized solar power may become the favored method of tapping the sun in the next few years.
And then of course, there's the cost. Desertec's price tag is projected to be $774 billion, or 400 billion euros.
Just 6 weeks ago, it was pegged at $555 billion.