Every year, each square kilometer of the desert receives solar energy equivalent to 1.5 million barrels of oil. Multiplying by the area of deserts in Africa or in the world, this is several hundred times as much energy as the world uses in a year. What this means is that in Africa, countries like Algeria, Angola, Libya and Nigeria can move directly from being oil-rich to being solar-rich, well assuming they emulate United Arab Emirate and invest their earnings from oil in technologies such as CSP to harness energy from the richly and freely available sunlight in the Sahara, Kalahari and Namib deserts.
Areas in the world with high solar insolation include sahara, Kalahari and Namib deserts
For a country like Nigeria, this would mean, the region in the north instead of the southern Niger delta region, would now be the energy power house, since electricity from solar thermal power plants located in the parts of the North that lies in the arid Sahel zone, would be sold both locally in Africa and possibly exported to Europe to generate more revenue than what Nigeria currently earns from petroleum export. CSP technology is the most suitable solar based technology to put this enormous amount of solar energy to use.
The principle behind CSP is very basic and should be familiar to anyone who had once used a lens or a mirror to focus sunlight to lit bonfire at campground in the wood or at festival ground, or to burn a hole onto a sheet of paper. Similarly, mirrors or reflectors of various shapes are used in CSP systems to focus sunlight to a surface to generate heat. The heat is then used to boil water to generate steam which then drives turbines to generate electricity: - this is basically how a solar thermal power plant works.
Should you, now that you are fascinated with solar heat, desire to make your coal-fired power plant “clean” by using clean concentrated solar heat, instead of “dirty” coal to fire it, if so, then you need to make the following preliminary considerations to determine the amount of solar heat that you would need. Now, using coal, depending on the capacity of the power plant, 400-700 °C heat could be generated to produce enough steam to drive the turbines of the coal-fired power plant. Therefore the lens you once used to burn a hole on a sheet of paper or lit campfire, would be ineffective here, rather it is only a mega sized mirror or a collection of mirrors, about the size of a football field is (are) capable of concentrating sunlight(beams) to generate heat of 400-700°C, and in order to generate this amount of heat fast enough, you need to site the mirror(s) in a place that receives a mega amount of daily sunshine.
Some of the world deserts are among the few places on earth that meet these requirements. No wonder the site of the first concentrating solar power plant was the desert: - in the California's Mojave Desert, to be precise.
Solar thermal power plants, with the exception of solar updraft tower, can only use direct sunlight, also known as Direct Normal Irradiation (DNI). This is the fraction of sunlight which is not absorbed or reflected by the atmosphere, i. e not deviated by clouds, fumes or dust in the atmosphere and that reaches the earth’s surface in parallel beams for concentration. Therefore, in addition to the availability of large open space and sunshine, solar thermal power plants are sited in regions with high direct solar irradiation.
A site or region is deemed suitable if it receives at least 2,000 kilowatt hours (kWh) of sunlight radiation per m2 annually, while the best site locations receive more than 2,800 kWh/ m2 / year. Ideal site regions, are where the climate and vegetation do not produce high levels of atmospheric humidity, dust and fumes, they include steppes, bush, savannas, semi-deserts and true deserts, located within less than 40 degrees of latitude north or south.
In Africa, Sahara and to some extent Kalahari and Namib deserts offer large uninhabited open space for mega-size-mirrors or reflectors (concentrators), and have high average daily irradiance, therefore are considered good and suitable sites respectively for concentrated solar power installations or solar thermal power plants (good consideration have to be made though, of the fact that Kalahari and Namib are inhabited to some extent).
Africa is the only region in the world which has many sites. Apart from the deserts, Africa's Sahel Stepes and Savanna Grassland which stretch across Africa from the East to the West are also considered suitable for solar thermal installations.
The total amount of energy irradiated from the sun to the sunbelt regions in Africa is enough to provide for annual energy consumption in Africa and Europe several folds. Blessed with tremendous amount of “solar resource” as well as “desert resource”, Africa is a continent to behold. Desert resource?- that’s right, desert is today a high value resource, just yesterday it was a desolate waste land. What a difference today makes! Thanks to quest for clean, cheap energy, Africa’s deserts and its surroundings are no longer regarded as the epicenter of drought and famine, and “Mecca” to European Aid Organizations and Aid-business organizations rather they serve today as “clean energy resource centers” patronized by crème de la crème of European industrialists and blue chip companies. In the same vain, thanks to Africa’s solar and desert resources the end of Africa’s energy misery could be nearer than envisaged.
In Europe, where there is no deserts, an organization called Trans Mediterranean Renewable Energy Cooperation (TREC), also known as DESERTEC, has proposed developing large-scale solar thermal plants in the North Africa section of the Sahara desert and transmitting the power to Europe through high-voltage direct current power lines.
The significant difference between the European current concept of clean solar energy from African desert and its forerunner in Kramer Junction plant in California's Mojave Desert, built in the 1980s with a total output of 354 MW is this: the solar thermal plants as operated at the California power plants is a hybrid system incorporating an auxiliary heating with fossil fuels. The European plan involves stand a-lone solar thermal plants, in which the solar energy generating system uses nothing other than the energy from the sun: - to demonstrate that environmental friendly solar thermal power plants can be a source of secure energy supply, be operated profitably and sustainable.
Following the questioning of the rational of producing solar energy in African desert for Europe, while the rest of Africa is left out of the project, a decision was reached to set up DESERTEC-Africa to extend the concept of “clean electricity from desert” to the rest of Africa. The only difference is that clean energy generated in Africa’s sunny backyard would be transmitted via High Voltage Direct Current (HVDC) within Africa rather than from Africa to Europe. In this case African countries or corporate organizations would set up alongside Europeans, solar thermal power stations in the Sahara desert as well as in other African deserts.
(insert here a map of Africa showing hvdc transmission lines across africa)
Our enthusiasm for CSP is based on its excellent prospect for Africa's development. That is why Desertec-Africa campaigns for its adoption by African countries, to harness electricity from the sun.
If you think it is an overstatement, to assert that CSP is going to go down on record as a singular case of technology that ushered in a rapid transformation of Africa to a developed continent then you may want to think again: - because if Africa, rich in mineral resources transforms itself into energy giant: - able to produce enough electricity for itself and for the rest of the world, should use this electricity to process its vast mineral resources and export value-added finished products or intermediates instead of raw materials, as it is the case today, then it would be rather an understatement to say that Africa’s developmental transformations would dwarf current impressive development of China, a country that is not as blessed with mineral resources as Africa.