Published on December 14th, 2011 | by Charis Michelsen34
Solar Energy From the Sahara Desert Could Power the World – But Will It?
December 14th, 2011 by Charis Michelsen
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.
So What’s the Problem?
One of the difficulties in maintaining CSPs is the harsh desert itself; while damaging sandstorms are relatively rare, the troughs must be tilted away from the wind if it reaches a certain speed. Bodo Becker, operations manager at a German company specializing in building CSP plants designed for desert use, says that if the troughs are not moved away from high winds, they act like giant sails. (That’s definitely not good for the equipment.)
Keeping the troughs clean isn’t easy, either; dry cleaning technology is being developed, but it doesn’t quite work yet. Currently, water is used both to cool the heat transfer fluid and clean the array. It’s a lot of water, according to Becker, as reported by the Guardian:
“Due to the dusty conditions, we are witnessing about 2% degradation every day in performance, so we need to clean them daily. We use about 39 cubic meters [10,300 gallons] of demineralized water each day for cleaning across the whole site.”
The total cost of completing the project is a barrier, too – it’s currently estimated at over $500 billion USD. A number of recent climate conference attendees focused on the question of how Desertec could be financed; EU subsidies, tariffs added to European energy bills, and bank loans were all the subject of speculation.
What Does Africa Think?
There’s a pretty clear idea – particularly in Germany – of what Europe wants from Desertec, and even the beginnings of a plan to get there. The final question – which should perhaps be the first – is how Africa stands on the project. Specifically, those countries making up the Middle East North Africa (MENA) region – as that’s where the solar plants would be located – should have their say.
Daniel Ayuk Mbi Egbe of the African Network for Solar Energy is skeptical of the project in general, fearing that it smacks of exploitation. He is not alone in this reaction, as other MENA-based speakers at the conference raised similar concerns. According to the Guardian, Egbe said:
“Many Africans are skeptical [about Desertec]. [Europeans] make promises, but at the end of the day, they bring their engineers, they bring their equipment, and they go. It’s a new form of resource exploitation, just like in the past.”
Another concern is how much of the energy will be available locally and how much will be sent abroad. Most of the MENA region lacks universal access to electricity, and the need is expected to grow in the near future. The electricity available now is largely foreign, which is an unpalatable situation.
Obaid Amrane, a board member of the Moroccan Agency for Solar Energy, said that 42% of the electricity should be from renewable sources by 2020. “We will build extra capacity beyond what Morocco needs if someone wants us to,” he said, “but we will need a big share of the electricity produced by these projects.”
At Least We’re All Focusing on Renewable Energy This Time
While Desertec and its plants are moving along, other sources of green energy are also gaining momentum in Africa (and Europe, and the United States, and Asia…). Wind turbines and photovoltaic panels both have their supporters in countries such as Jordan, as both are less water-intensive than Desertec’s SCP plants, and solar towers with hundreds of pivoting mirrors also have staunch supporters.
Whichever way it goes, the move away from fossil fuels and towards renewable energy is heartening. Let us know what you think of the push for green energy from Africa, in the comments, below.
Keep up to date with all the hottest cleantech news by subscribing to our (free) cleantech newsletter, or keep an eye on sector-specific news by getting our (also free) solar energy newsletter, electric vehicle newsletter, or wind energy newsletter.