One potential technogy https://www.abc.net.au/news/2022-07-31/wave-power-generator-...
New thing I just learned. The tidal stream industry seem confident they can beat nuclear at shockingly low investment. https://interregtiger.com/understanding-tidal-stream-energy/
If they're not lying, that's your high return investment for the future (if you're a policy maker...if you are a private investor then what happened to the solar industry when panels got cheap could happen again).
* uncorrellated variable sources need less storage when combined There are already regions that can work on wind, solar, and a small percentage of existing hydro with no storage for this reason. Tidal isn't completely uncorrelated -- roughly once a month your peaks will line up with solar peak production, and the trough will line up with peak demand for a few days -- but attaching two systems at distance will help with this and it reduces the load on hydro.