Surface area of 380 km by 380 km (236 mi by 236 mi) in the Sahara desert required to power the world with solar energy only.
Concentrated solar power (CSP, also known as concentrating solar power, concentrated solar thermal) systems generate solar power by using mirrors or lenses to concentrate a large area of sunlight onto a receiver.
Electricity is generated when the concentrated light is converted to heat (solar thermal energy), which drives a heat engine (usually a steam turbine) connected to an electrical power generator or powers a thermochemical reaction.
CSP seems to be more suitable to the Sahara due to the direct sun, lack of clouds and high temperatures which makes it more efficient. The direct normal irradiation (DNI) is one of the most crucial aspects during the site selection and feasibility analysis for concentrating solar power systems. Direct Normal Irradiation (DNI) is the amount of solar radiation received per unit area by a surface that is always held perpendicular (or normal) to the rays that come in a straight line from the direction of the sun at its current position in the sky.
With an average DIN in the Sahara of 2,500 – 2,800 kWh/m²/yr, the annual electricity net output will be 0.16 TWh per 1 km2.
Let’s calculate how we can power the world:
If you install a CSP plant with an area of 143,253 square km (square of 380 km by 380 km (236 mi by 236 mi)), then the energy produced will be enough to cover the annual consumption of the world – 23,398 TWh.
For certain parts of the planet, a CSP plant of the following sizes is required:
Asia Pacific (11,614 TWh) – 71,106 km2 (square 267 km by 267 km (165 mi by 165 mi))
North America (5,151 TWh) – 31,537 km2 (square 178 km by 178 km (110 mi by 110 mi))
Europe (3,886 TWh) – 23,792 km2 (square 154 km by 154 km (95 mi by 95 mi))
Eurasia (1,237 TWh) – 7,573 km2 (square 87 km by 87 km (54 mi by 54 mi))
Central & South America (1,103 TWh) – 6,753 km2 (square 82 km by 82 km (51 mi by 51 mi))
Middle East (1,023 TWh) – 6,263 km2 (square 79 km by 79 km (49 mi by 49 mi))
Africa (722 TWh) – 4,420 km2 (square 66 km by 66 km (41 mi by 41 mi)).
To calculate our data, we took info from Crescent Dunes Solar Energy Project as an example:
Total collector area: 296 acres (1,200,000 m2)
Site resource: 2,685 kW·h/m2/yr
Annual net output: 196 GW·h over 1 year
Annual electricity net output per 1 km2 = 196 GWh / 1.2 km2 = 163 GWh/km2 = 0.16 TWh/km2