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A Green Energy Dream Grows in the Sahara

Japanese academics plan an energy utopia in the Sahara, complete with superconductors and home-brewed silicon photovoltaics

4 min read

A Green Energy Dream Grows in the Sahara

4 October 2011—"People say it’s a Don Quixote project," says Hideomi Koinuma. He grins. He chuckles. "That means they think it’s a crazy project." He completely cracks up. Being compared to an eccentric knight who embarks on grand but impossible quests apparently doesn’t bother him in the slightest.

Koinuma, a professor at the University of Tokyo, is the dreamer behind the Sahara Solar Breeder Project, a proposal that he says could supply a major portion of the world’s energy. The idea: Perfect a process that turns the Sahara’s sand into high-purity silicon suitable for making solar panels, build factories in Algeria to churn out those photovoltaic panels, and establish solar power stations throughout empty desert land. Then send the abundant clean electricity produced across vast distances—around Africa, Europe, and the Middle East—via high-temperature superconducting transmission lines.

It’s an outrageously ambitious plan, but Koinuma has a knack for convincing people that it can and must be accomplished. He has persuaded the Japan Science and Technology Agency and the Japan International Cooperation Agency to jointly fund the project for five years at about US $1 million per year, and the Ministry of Higher Education in Algeria has pitched in some money as well. This August, collaborators from around the world gathered at a meeting in Japan to discuss the project’s next steps.

"It’s all possible scientifically," says Koinuma, "but there are still technical problems to overcome." His role is to investigate the production of high-purity silicon from Sahara sand, which he says can be accomplished by improving on the Siemens process, a technique dating from the 1950s that’s commonly used to produce pure silicon. Koinuma thinks it will be possible to increase efficiencies in the purification process and create high yields of pure silicon from desert sand, but to test his ideas he needs fancy, custom-designed furnaces and "more money," he says bluntly.

sahara solar breeder model

Illustration: Sahara Solar Breeder Foundation
Click on image to enlarge.

That brings up another reason why he’s interested in cooperating with Algeria and other countries in North Africa and the Middle East. "Arabic countries are very interested in solar energy," says Koinuma. "They know that they are rich right now because of oil, but the oil is not infinite—maybe in 50 years their oil wells will dry up. So now, while they’re getting a lot of money from oil, they must invest and plan for the next energy."

Koinuma and his colleagues aren’t the only ones who see big energy potential in the sun-baked Sahara. Germany’s Desertec Foundation and France’s Medgrid project both advocate building renewable power stations throughout North Africa and the Middle East.

These two European organizations, which have both governmental and industrial backing, are further advanced than the Sahara Solar Breeder Project, but Desertec’s director says Koinuma’s proposals are welcome. "Every idea offering a solution for a world with a growing population, dwindling fossil fuels, and ecological challenges needs to be considered," says Thiemo Gropp, director and cofounder of the Desertec Foundation.

However, there are distinct differences in the groups’ approaches. Desertec and Medgrid both argue that photovoltaic solar cells are inferior to solar thermal power stations (where reflectors produce heat to turn a turbine), because the latter’s energy can be more easily stored to produce power at night.

The two European organizations also advocate the construction of high-voltage direct-current (HVDC) transmission lines to connect North Africa and Europe. Gropp argues that the Sahara Solar Breeder Project’s reliance on superconducting transmission lines, which are far from being commercially available, is a serious drawback. "Their plan to circulate electricity over extremely long distances would result in huge energy losses unless they use superconductor technology. Their proposal could not be realized using HVDC lines," says Gropp.

Photo: Satarou Yamaguchi

Tackling the daunting superconducting challenge for the Sahara Solar Breeder Project is Satarou Yamaguchi, a professor at Chubu University and a man whose business card reads "Acta, non verba," which, roughly translated, means "actions, not words." In keeping with his motto, he has tangible technology to show for his efforts. In 2006, Yamaguchi constructed a 20-meter superconducting transmission line that conducted DC power at the relatively high temperature of 77 kelvins (–196 °C). "It was the first experimental device of this kind in the world," Yamaguchi says proudly. In 2010, he completed a new line that measures 200 meters.

Yamaguchi says a superconducting transmission network linking the Sahara and Europe is theoretically possible: He imagines refrigerator stations every 100 kilometers to pump liquid nitrogen coolant through the lines. "With high-temperature superconductor systems, the cost of the cable is high, but the cost of the refrigerant is low," he says. He’s now looking for funding to build a 2-km test line.

Like his colleague Koinuma, Yamaguchi also sees enormous global potential in this project. "In the Cold War time, the ICBM [intercontinental ballistic missile] was called the ’peacekeeper,’ because people were very afraid of war," he says. "But if we connect the world with these transmission lines, they’ll be the new peacekeepers. Neighbor countries will have to keep good relations to get energy, even if they do not like each other." Such energy interdependence may not have convinced countries to get along in the past, but Yamaguchi is an optimist.

Other experts in superconductor technology are impressed with Yamaguchi’s achievements, but they say there’s a long way to go before his cables can bring about world peace. "Yamaguchi has actually built a high-temperature cable, which is very exciting," says Steven Eckroad, who manages a program on superconductivity’s power applications for the Electric Power Research Institute. "And superconducting DC cables have some real benefits—for transmission of large amounts of power over long distances, I think it’s a technology well worth developing. But I think a practical DC superconducting cable is probably 10 years out," Eckroad says.

Eckroad also thinks that such cables would be better suited for long-distance transmission over land—for example, from wind farms in the American interior to cities on the distant coasts. "The idea of bringing power to Europe from North Africa using superconducting cables is a real stretch," Eckroad continues. How to install superconducting cables and their requisite refrigeration stations under the Mediterranean Sea is a question still to be answered.

The researchers behind the Sahara Solar Breeder Project are certainly aware that they’re taking on big challenges. But with the dire consequences of other energy choices on full display—the Fukushima nuclear disaster, the BP oil spill, and others—Koinuma says it’s crazy not to dream of big clean-energy solutions. "So the people who say my project is Quixote are Quixote from my viewpoint!" He cracks up again.

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