Japan has just installed a 1.1MW tidal turbine, which has a 97% capacity (as far as i understand). This would mean that given Japan's annual energy usage of 902,769,000 MWh/year it would take 96,439 turbines for the country to become 100% energy independent and clean.
https://proteusmr.com/2025/02/13/proteus-marine-renewables-installs-japans-first-1-1mw-tidal-turbine/