Solar panels can have more than 200 watts peak per square meter and provide around 200 kWh per year and square meter, although these values vary a lot depending on where the panels are installed.
Given these numbers, generating 200 TWh annually (which is more than the current electric energy consumption of Bitcoin mining devices) would require 10^9 square meters; that’s slightly more than 31 square kilometers.
Don’t misunderstand this as defending the electric energy consumption of Bitcoin mining! I’d rather see this electric energy being used elsewhere.
I merely wanted to show how much electric energy can be harvested using solar panels.