The actual delta is indeed huge, but there were some mistakes in your calculation that result in an answer that is off by some orders of magnitude.

Assuming your initial numbers are correct, the approx 1e10 should be 1e7 (rounding down from 4.5e7), as 1 million sqm equals 1 sqkm (this is different from 1 kilo square meter; see cube square law etc.)

You also do not take into account that solar panels have an expected lifetime of over 20 years - your current calculation seems to want a panel produced every year for every field.

Taking these into account brings the production defecit factor down to ~ 1e5, which is still unfathomably huge but at least marginally more achievable than the 1e9 answer you got.