Let's calculate...

The "World" square is 300x300km.

That's 90,000 m^2

Modern solar panels are around 15% efficient, producing 150W / m^2 at peak generation.

In sunny places like the Sahara, daily energy production per square meter is around 1125W-h/day

This is 4.05 Megajoules per day x 365 = 1.478 Gigajoules per year

4,050,000 * 90,000 = 133x10^12 Joules or 364 Terajoules

The world uses 606 Exajoules per year

https://www.iea.org/reports/key-world-energy-statistics-2021/supply

That's 606 x 10^18 Joules

That means we would need (606x10^18) / (133x10^12) x 90000 = 410 x 10^9 m^2 of area.

This is an area of 640km per side if the panels were butted up against each other.

In reality it would be more like 1000km per side.

This image is incorrect.

All the squares would be 3x larger.

Feel free to check my math.