Most tidal I am familiar with capable of generating anything approaching reasonable amounts causes significant ecosystem impacts- you basically replace entire shorelines with concrete bunkers that act as a crappy gravity battery (you can get significant mass from the water, but not much lift from the tide).

I think most research is focused on utilizing less unique space- rooftops, open plains, open ocean. Shorelines are tiny spaces for how ecologically unique they are, plus they tend to be highly desirable for other human uses as well.

Hawaii is actually pretty worse case for tidal power. You want a narrow estuary with a high tidal swing. Think fjords and similar formations.

I saw a marketing video for one company that was deploying a prototype to do this a few days ago. I'm unable to remember the name or find a link.

I think it was somewhere in oceania that they were installing the protoype in. The unit looked sort of like (this)[https://imgur.com/a/ymulbWF] but wider and in hd of course.

By wider I mean it looked more like a catamaran style boat and the one in the imgur link is more like a monohull boat. The one in the video which they deployed maybe 15-30 yards off shore from a beach was where they installed it and it had branding from their company on the side and some bright yellow accents.

It’s still impossible to do on a practical basis.

Fortunately there are still people working on it.