Tidal power

Are there any tidal power stations that are are not anchored and are just foating over the serface of water having no connection to the solid ground? Can you suggest a data based of research papers on the subject?

None that are actually generating, but there are systems under development, e.g. Evopod (http://www.oceanflowenergy.com/)

P.S. The device floats, but is still anchored, otherwise it would gather a lot less energy as it would simply drift with the tide and there'd be no way to feed the power to the land.