# How large would a solar panel array need to be in order to supply all the world's energy?

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

• What is the energy requirement in 2021? Aug 9 at 15:03
• According to the IAEA it was 617 exajoules in 2019: iea.org/reports/world-energy-balances-overview
– tomh
Aug 9 at 15:35
– tomh
Aug 9 at 15:49
• 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? Aug 9 at 23:03
• Of course, it needs to repay it's energy cost of production and installation out of it's own production. Aug 10 at 1:34

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.
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%.