Wrong. You are are assuming that is 24/7/365You are also...

Wrong. You are are assuming that is 24/7/365
You are also omitting the transmission costs
Solar at best is available for 6-8 hours and it is intermittent during that period. So it averages a fraction of that and has large variances
1 sq km cannot power 500k houses
How does that compare to coal/gas/nuclear, the output of these 3 modalities dwarfs wind and solar
Offshore wind? That is pure folly and environmental destructive

Here is a basic comparison comparing wind with coal. Coal wins hands down. Nuclear does far better

https://papundits.wordpress.com/2018/11/25/is-wind-power-actually-cheaper-than-coal-fired-power-well-no/