Argument: Oceans corrode wave power systems, which is costly
Umbra Fisk. "Getting Sloshed. On wave power". 1 Aug 2007 - "Interesting design problems with wave power include the destructive power of the salty sea -- corrosion and weather and storms and all."
David Phillips. "Wave Power Still Not on the U.S. Horizon". Energy Industry. 8 Apr. 2008 - "A key challenge remains in moving aqua-boy technology beyond proof-of-concept to commercial viability. In November 2007, Finavera’s prototype AquaBuOY 2.0 sank off the Oregon coast, for reasons still yet to be disclosed."