Wave energy seems like it holds some promise for a renewable resource.  Essentially, it is concentrated wind energy, since waves are formed by wind across large areas of water.  Capturing it has it difficulties, marine environments are tough on moving parts, tough to maintain, and frequently create energy that must then be transported somewhere.    Searaser seems to have a cool idea, but it's not immediately clear why this is better than other similar wave energy harvesting ideas.  

Via http://www.engadget.com/2008/11/19/searaser-floating-pump-will-use-the-oceans-waves-to-generate-po/