Solar nets 10 watts per square meter (give or take a fraction).
That’s it.
Ergo 1 square mile for 25 megawatts.
Math accordingly.
RE: 1 square mile for 25 megawatts.
I almost always used the handy formula 1 MW = 1,000 homes. So, one square mile of Solar can power 25,000 homes, or for an average of 4 people per home, a small city of 100,000 people.