Tidal and wave power is expensive

renewable energy costs
Tidal and wave power remains a pricey way of creating power. The ocean is a rough place to site energy generation, and then there’s the question of getting the power to shore reliably. Salt, corrosion, and water turbulence takes a toll.

There’s plenty of R&D going on in tidal and wave power. Hopefully someday soon they’ll figure out how to do it reliably and inexpensively.