SeaGen (the subsidiary company of Marine Current Turbines), is the 1st to go commercial with tidal wave power generators. SeaGen just started the new installation at Strangford Lough, the largest inlet in the United Kingdom.

SeaGen have developed technology to install off the coast of Ireland for electricity production by harnessing ocean currents. This new installation, if successful, will be used throughout the coastal regions of the United Kingdom.

Source Article:
MIT’s Technology Review: First Tidal Power Generator