I think it's a pretty neat method and seems to have a lot of potential to be commercialized. I bet they'll eventually figure out how to replace the glass with a flexible membrane that would make construction and operation somewhat simpler and cheaper.
Anyplace there is a decent temperature difference can be utilized to make power, such as oceanic temp differences between deep water and surface water, using either direct turbine drives like you show above, or a heat engine that really lights my fire are the Sterling cycle engines
http://en.wikipedia.org/wiki/Stirling_cycle