[etskinner]

They address this in the article: Only twice per year are the panels in shadow, at the equinoxes. Presumably all the rest of the time they're slightly above/below the earth with respect to its orbit. It's the same reason the moon is lit nearly all the time.

[mlyle]

> It's the same reason the moon is lit nearly all the time.

The moon is 10x further away, so the Earth subtends/shades a much smaller angle.

[DennisP]

A geostationary satellite gets eclipsed more than the moon but it's still in full sun 99.5% of the time.