I know very little about the power generation industry, which is perhaps why I'm confused, but I have a question about the capacity and output math.
Once you calculate running hours I would expect you would need to know the output per hour. Then total output/capacity would be running hours * output per hour. Then I'd expect to compare the total annual output capacity to Mr. Friday's needs (5 KWh) to see if either method (offshore/onshore) meets his power needs. For example, if this were a case about widgets, I'd calculate Ms. Robinson's capacity by multiplying the number of widgets per hour she could manufacture * the number of hours she worked per year. Then I'd compare that capacity against Mr. Friday's widget needs.
Is there something about power generation I don't understand?