2
$\begingroup$

This story from 2016 claims that all the world's energy needs could be supplied by covering 1% of the Sahara in solar PV panels.

Was (is?) this true, and if not, how would you go about approximating the size of solar PV array needed to supply the world's energy in 2021?

According to the IAEA world energy consumption was 617 ExaJoules in 2020:

https://www.iea.org/reports/world-energy-balances-overview

$\endgroup$
5
  • $\begingroup$ What is the energy requirement in 2021? $\endgroup$
    – Solar Mike
    Aug 9 at 15:03
  • $\begingroup$ According to the IAEA it was 617 exajoules in 2019: iea.org/reports/world-energy-balances-overview $\endgroup$
    – tomh
    Aug 9 at 15:35
  • $\begingroup$ Good point - added $\endgroup$
    – tomh
    Aug 9 at 15:49
  • $\begingroup$ LShaver's answer is a good one (imo), but I suspect you want to know how much of the world would practically need to be covered? What I mean is, I think using the Sahara is a red herring. Are we also going to account for battery storage, transmission lines, transformers, etc? $\endgroup$
    – TCooper
    Aug 9 at 23:03
  • $\begingroup$ Of course, it needs to repay it's energy cost of production and installation out of it's own production. $\endgroup$
    – Phil Sweet
    Aug 10 at 1:34
4
$\begingroup$

The U.S. National Renewable Energy Lab did a study of solar installations in the U.S. in 2013 and determined that for large-scale solar PV systems, 7.9 acres (31,970 $m^2$) of land are required on average for 1 $MW_{ac}$ of power capacity (from Table ES-1). This is based on analysis of 72% of existing installations in the country, so this is a good real-world estimate of how much space is required in practice. Because this is looking at capacity, this space estimate will translate to any location. Generation is a different question, of course.

According to the IEA, world energy use in 2020 was 606 exajoules, or 168,333 TWh. (Note that this includes oil and gas, not just electric energy.)

I used PVWatts to see how much energy a solar array in the Sahara can produce. Unsurprisingly there aren't a lot of weather stations in the Sahara, so I used Aswan, Egypt as a proxy -- wrong longitude, right latitude. Here, a 1.2 $MW_{dc}$ array would produce 1 $MW_{ac}$ capacity and 2,204 MWh of energy. To get to the global consumption, we'd need 76,375,545 of these, covering an area of 2,441,741 $km^2$.

The Sahara Desert is 9.2 million $km^2$, so this represents about 27%.

$\endgroup$
1
  • $\begingroup$ 'U.S. National Renewable Energy Lab ... determined that for large-scale solar PV systems, 7.9 acres (31,970 m2) of land are required on average for 1 MWac of power capacity' That implies a very sparse packing of the solar panels on the site. Presumably, if one were in a situation where scarcity of land was an issue, one could pack them more tightly (the limit being when they start to shade each other). $\endgroup$ Aug 13 at 12:29

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.