PRL Media/news, page-358

Utility scale renewables CAPEX can be $1-1.5m per 1MW of power generation once LGCs are factored in.

The desalination plant (as I am unaware of commercial scale technology to directly process seawater), electrolysers, BOP and other infrastructure is harder to quantify due to the fact that there are no operating green hydrogen projects of this scale currently.

For a better comparison point currently, I'd refer to the AREH project. 26GW, 3GW power gen to be delivered to users, balance to be utilised for green ammonia production. Reports of CAPEX of circa $28bn (would need to confirm sources though)