I have heard there is one tidal basin plant on a fiord in Scandanavia.
Imagine the amount of water that flows in and out of places like Chesapeake Bay, San Fancisco Bay, Puget Sound, etc every day.
Huge potential. Someone should be working on it.
Sure salt water is corrosive. But steel hulled ships seem to serve for up to 50 years. Long enough to do the job.