The equipment is likely to be more expensive since it needs to live underwater, but installation might be less expensive since no supporting tower would be needed. Maintenance costs might be higher but maintenance frequency might be less due to less stress for a generator sited in less buffeting conditions.

But tides, and especially Gulf Stream water would be more consistent than wind thus spreading equipment costs over more hours of generation.

For example, tomorrow San Diego experiences a low tide at 2:39am. For LA the low point arrives at 5:39am and Seattle’s morning low tide is 11:26am.

Were we to hook tidal generators to the existing HVDC transmission lines which already run along the West Coast we could count on tidal power 24/365.

Then there the Gulf Stream. That’s an always-on ~4MPH energy source.