Something New Under the Sun: Solar in the Sahara

The venture, known as Desertec, aims to spend US $500 billion over the next 40 years to generate up to 100 gigawatts (GW) of electricity in North Africa and the Middle East, spanning an arc from Turkey through Saudi Arabia to Morocco. Initial steps involve analyzing the technical, economic, political, social and ecological issues that will need to be addressed to move the project forward.

The idea of harvesting the prodigious solar resources of the Sahara and neighboring desert regions has been talked about for several years. What’s moving it forward now is the commitment by the member states of the European Union to reduce their GHG emissions by 80 percent below 1990 levels by 2050 as was agreed to under the Kyoto protocol. Notwithstanding the inroads Denmark, Germany, Spain and other European nations have made to date in embracing wind and solar power, meeting this GHG reduction obligation will require the Europeans to quickly move to a much higher level of engagement with renewable energy.

Why the Sahara?

Straddling the Tropic of Cancer, the Sahara and the deserts of the Middle East are home to what are possibly the sunniest days this side of Mars. The driest parts of the Sahara receive as little as 2 cm of rain per year, while rainfall on the wettest regions averages 4 inches annually, considerably less than the 5 inches per year averaged in the Mojave Desert, a focal point of solar farming right now in the United States. 

The amount of solar energy falling upon the earth's desert regions during 6 hours of a typical day equals the total amount of energy from all sources consumed by the entire population of the globe in a year's time. The Sahara itself encompasses over 154,000 square miles, a number that can be almost doubled if neighboring deserts are factored in. According to Desertec, covering just 0.3 percent of this expanse with solar power generating facilities could meet the entire electrical demand of continental Europe.

Key Concerns

Of course not all of the Sahara is ideal for solar power. Constantly shifting sand dunes that can reach 150 feet high rule out the arid area’s innermost environs and security is also an issue.

The first CSP facilities will probably be located on the desert’s northern perimeter, in Algeria, Morocco and Tunisia. These are relatively stable counties with westward leaning governments, although the possibility of sabotage to isolated transmission towers in the face of localized insurgencies cannot be overlooked. Expanding the Desertec network to the countries of the Middle East and possibly the Sahara’s southern rim to serve countries in central Africa would magnify security concerns. 

The required transmission network will be costly and complex in a region that currently lacks extensive transmission infrastructure. Included will be 20 or more under-water cables to move electricity from where it is generated to Europe beneath the Mediterranean Sea. The underwater lines will be HVDC, which can transmit power over long distances and through water without the significant line loss associated with conventional AC transmission.

Another key challenge is water availability. Much of the Sahara experiences strong winds and ferocious sand storms are not uncommon. This has led Desertec to choose solar thermal (CSP) facilities instead of photovoltaics (PV), whose panels can be fouled by exposure to grainy particulate matter. To obtain the large quantities of water needed for CSP generation cooling and steam turbine operation, the venture envisions construction of desalinization plants that would draw water out of the Mediterranean. Electricity generated by Desertec would be shared throughout North Africa and the Middle East.

Key Benefits

By providing affordable access to this renewable electricity, Desertec would help address what is the key complaint leveled by developing countries against mandatory GHG emission reduction targets: that of imperiling their prospects for economic development if forced to abandon or scale back hydrocarbon electricity generation.

Another key issue for developing nations would also be addressed by Desertec.  Water from the desalinization plants could be used to expand agricultural production in the region’s developing economies, helping to address the need for increased food production as the earth’s population rises to a projected 10 billion by 2050.

Finally, the model could also be transferred to other parts of the world, including North America. The Sonorant Desert of Northern Mexico has tremendous solar potential. Cross-border transmission from utility-scale solar farms established there could help fuel America’s transition to a clean energy economy while supplying renewable energy to Mexico, where natural gas, diesel and especially fuel oil currently account for almost 70 percent of total electricity generation in the nation of 107 million. 

The Desertec plan is ambitious, with hopes to have the first of its solar farms up and running within 10 years. If successful, it may not be just camel caravans that crisscross the Sahara in the future, but transmission lines, CSP facilities and power towers as well.

Matt Slavin is president of Portland, Oregon based Sustainability Consulting Group.