I think you're off by an order of magnitude there. Intensity should be somewhere between 150 to 300 watts per sq meter per 24 hours. At 200 watts per sq meter that works out to 5 sq km. Estimating 50% panel efficiency that's 10 sq km.

To hit 100 sq km at 50% panel efficiency would mean averaging 20 watts per sq meter (obviously wrong). Even assuming a paltry 10% panel efficiency would only get you to 100 watts per sq meter.