Sahara as we know it

The Sahara is the largest hot desert and the third largest desert in the world after Antarctica and the Arctic. Its area of 9,200,000 square kilometres (3,600,000 sq mi) is comparable to the area of China or the United States.

The desert comprises much of North Africa, excluding the fertile region on the Mediterranean Sea coast, the Atlas Mountains of the Maghreb, and the Nile Valley in Egypt and Sudan. It stretches from the Red Sea in the east and the Mediterranean in the north to the Atlantic Ocean in the west, where the landscape gradually changes from desert to coastal plains. To the south, it is bounded by the Sahel, a belt of semi-arid tropical savanna around the Niger River valley and the Sudan Region of Sub-Saharan Africa.

The Sahara can be divided into several regions including: the western Sahara, the central Ahaggar Mountains, the Tibesti Mountains, the Aïr Mountains, the Ténérédesert, and the Libyan Desert.

The name 'Sahara' is derived from ṣaḥārā the plural of the Arabic word for "desert".

Climate and geography of the Sahara

The Sahara’s northeasterly winds can reach hurricane level and often give rise to sand storms and dust devils. Half of the Sahara receives less than an inch of rain per year, and the rest receives up to 4 inches (10 centimeters) per year. The infrequent rain is usually torrential.The highest peak in the Sahara is the volcano Emi Koussi (11,204 feet or 3,415 meters) in the Tibesti Mountains in northern Chad. The desert’s other mountains and mountain ranges include the Aïr Mountains, Hoggar (Ahaggar) Mountains, Saharan Atlas, Tibesti Mountains, Adrar des Iforas and the Red Sea hills.Many people imagine the Sahara as dotted with sand dunes, and the desert does have its share of ergs, which are large areas of shifting sand dunes, with some of some of them reaching 590 feet (180 meters). However, most of the Sahara is characterized as rocky hamada, a type of desert landscape that has very little sand and is made up of primarily barren, hard, rocky plateaus.With the exception of the Nile River, the Sahara’s rivers and streams are irregular or seasonal. The Nile crosses the desert from its origins in central Africa to empty into the Mediterranean.The central part of the Sahara has extremely limited vegetation. The northern and southern reaches of the desert, along with the highlands, have areas of sparse grassland and desert shrub, with trees and taller shrubs.

Sahara solar power

Life might take a hammering on the sun’s earthly anvil, the Sahara desert, but the two most abundant resources the desert has to offer – sunlight and sand – could help solar power to “breed” and thrive there.

The Sahara Solar Breeder Project is a joint initiative by universities in Japan and Algeria that aims to build enough solar power stations by 2050 to supply 50 per cent of the energy used by humanity.

The idea is to begin by building a small number of silicon manufacturing plants in the Sahara, each turning the desert sand into the high-quality silicon needed to build solar panels. Once those panels are operating, some of the energy they generate will be used to build more silicon plants, each churning out more solar panels and generating more energy that can be used to build even more plants, and so on.

Hideomi Koinuma at the University of Tokyo leads the Japanese end of the project. He admits that making silicon panels from the rough sands of the Sahara or other deserts has not been attempted before, but says it is a logical choice.

“From the viewpoints of quality, quantity and chemistry, Sahara sand is hard to beat for use as silicon for solar cells,” he says.

Desertec has a more modest goal – it is dedicated to supplying only 15 per cent of Europe’s electricity by 2050. Nor does Desertec plan to use Sahara sand for its solar panels.

Desertec hails the new breeder project as “a positive contribution towards climate protection”. However, a spokesman said he was puzzled over the choice of energy delivery by the new scheme.

Koinuma wants to use “high-temperature” superconductors to distribute the power as direct current – more efficient than a conventional alternating current. Despite their name, high-temperature superconductors typically operate at around -240 °C, and the long power lines will require a formidable cooling system.

“There is not really a need for superconductors. By using high-voltage direct current transmission lines it is possible to transport clean power from the deserts over long distances to centres of consumption,” says the Desertec spokesman – adding that the technology is already used in dozens of projects worldwide.

“Transmission losses are fairly low – around 3 per cent per 1000 kilometres. Unlike superconductors, there is no need for cooling, while power transmission costs are just 1¢ to 2¢ per kilowatt-hour.”

Koinuma disagrees. He sees the potential for linking the Sahara-powered stations to a special network of supercooled high-voltage DC grids for transporting electricity 500 kilometres or more.

Even if we need to cool the grid line with liquid nitrogen, the system could be cost-competitive,” he claims[1]

Sahara desert project aims to power half the world

Farming the Sahara

The SFP (Sahara Forest Project) has developed a model based on using resources that are abundant to deliver scarcities. This principle will be reflected in the core technologies of the Tunisian facility.

The desert sun will be harnessed for solar power to heat and electrify the site. Seawater will be piped in to cool greenhouses and allow year-round cultivation of crops, a 'biomimicry' process inspired by the Namibian fog-basking beetle.

Cucumbers from the Qatar pilot, which delivered similar volume to European farms.

Seawater will also be desalinated to extract both salt and fresh water, and the humidity of the greenhouses will be used to spur the growth of new plant life outside the facility, in the hope of regenerating a wider ecosystem.

The methods may seem far-fetched, but a successful pilot of the model in Qatar produced vegetables at a comparable rate to European farms over three crops a year, while plants multiplied rapidly around it. A scaled up facility is under construction in Jordan.

Hauge says that efficiency has improved as the group have learned to adapt their model to particular conditions.

"We have learned more about the value of local knowledge," he says, adding that the Tunisian project would rely on local talent across a spectrum of jobs from farming to highly-skilled, technical positions.

Hauge hopes the project, and its local employees, can inspire growth in the nation's renewable sector.

Right place, right time

Tunisia was chosen as the site for the project on October 9, 2015 -- the day a group of Tunisian activists were awarded the Nobel Peace Prize for their role in the 2011 "Jasmine Revolution" that preceded a transition to democracy.[2]

Solar Power + Salt Water = Sahara Forest

"Among the biggest problems in the entire region of Northern Africa and the Arab countries are the dust and sand storms that constantly cover up solar panels and get into all machinery that is exposed."

However, Hirt believes that the SFP is "worth the effort and will teach us more how to transform these vast regions of unused land back into agriculture."