I always thought that tides were a really underutilized source of energy.
I mean, look at the Bay of Fundy. The equivalent of all the water in all the rivers in the entire world cycles in and out every single day. Thats a lot of movement and a ton of potential energy there.
As the article notes, part of the problem with large-scale operations like this in the past is that they disrupted ocean life to a significant degree; this one is different in that it (theoretically) doesn't, since it's smaller and mobile and not tethered to the seabed.