Aquanator:Energy from the seas

Surfing the net, i found this interesting article:
www.abc.net.au...

which explains more of getting energy from the oceans and seas.I noe, its a while back, but shouldnt they have completed a complete system by now?N if put to use, a whole lot of free energy could be obtained for all the coastline countries n cities. Wad do u guys tink?