By Charis Michelsen, via CleanTechnica,
The African desert is hot. It gets a lot of sun. These are facts that we all know, even if we have no personal experience (and for those of you who haven’t been there, let me assure you, it’s true). It seems intuitive that the intensity of the sunlight pressing down on that desert makes the area ideal for generating solar power, and indeed – such plans were conceived in 1913 (by American engineer Frank Shuman), and again explored in 1986 (by German particle physicist Gerhard Knies).
Both Shuman and Knies strongly believed desert solar energy was necessary; Shuman believed that humanity would revert to barbarism without it, and Knies felt that it was the only way to avoid dirty and dangerous fossil fuels.
Knies even went so far as to say that the desert received enough energy in a few hours to power the world for a year. While Shuman was thwarted by a world war, Knies spent two decades working to develop desert solar power as a viable energy source, and his efforts resulted in the project “Desertec.”
What is Desertec?
Desertec is a set of plans for a massive network of solar and wind farms stretching across the Mena region and intended to connect to Europe via high voltage direct current transmission cables (which are supposed to only lose 3% of their electricity per 1000km, or 620 miles).
Although Desertec has been widely regarded as nothing more than an unattainable dream for most of its history, it’s been gaining some momentum over the past two years. A number of significant German corporations – including E. ON, Munich Re, Siemens, and Deutsche Bank – have all signed on with the project, forming the Desertec Industrial Initiative (Dii). Germany’s decision to speed up the schedule to dismantle its nuclear power plants earlier this year has also helped generate more German support for Desertec, and the first phase of construction is set to begin in Morocco next year.
The Dii isn’t entirely German, although half the corporate representatives at its annual conference in Cairo last month hailed from that country, and the main component of the current technology (glass troughs, see below) are only made by German companies. Paul Van Son, Dii’s CEO, claims the project is international in nature. According to the Guardian, he said:
“Yes, the initiative came from Germany. But there are 15 different nationalities involved, including companies such as HSBC and Morgan Stanley. This is just the start.”
As noted in one of our roundup posts last month, the French (a big energy player, of course) are also getting on board the Desertec project now.
How It Works
Most of the solar energy would come from “concentrated solar power” plants, or CSP plants. The CSP plants use both natural gas and solar panels when generating electricity. Each plant holds a number of parabolic troughs – several yards tall – containing receiver tubes above a parabolic mirror and filled with an oil-like heat transfer fluid.
The fluid is heated to 400C (750F) and then used to heat steam in a standard turbine generator. The fluid is then cooled before it is returned to the receiver tubes. During the day, the energy to heat the fluid is all solar; natural gas may be used at night to continue the process. However, the amount of energy produced by fossil fuels is legally limited to 27% of total output.