Comment on Ocean Energy Conversion

In response to my piece What Will Become of Most Renewable Energy Concepts? a reader notes:  Ocean energy conversion is fascinating and is doable.

Yes, ocean energy conversion, in each of its many forms (ocean current, tidal, wave, ocean thermal, etc.) is cool, but it’s currently expensive.  The point I was trying to make here was essentially: Who will win the race for a technology based on renewable resources that is the lowest cost, most scalable way to convert a given resource of energy into something useful?  For better or worse, it’s going to be hard for anything to catch up to the maturity (and thus levelized cost of the energy) represented by solar PV and wind.