The turbine, which sits more than 100ft below the waves, is now providing power for up to 30 homes on North Yell in Shetland, as well as an industrial estate.
The green energy device has been developed by Leith-based company Nova Innovation, together with North Yell Development Council.
The turbine has a rotating propeller, which is spun by the power of the tide. This then drives a generator that produces electricity, which is transmitted to the shore via an underwater cable.
The project has been funded with cash from the Scottish Government's Community and Renewable Energy Scheme as well as Shetland Islands Council and the North Yell Development Council.
Mr Ewing said: "For the first time, anywhere in the world, a community-owned tidal turbine is generating electricity. It will have a positive impact on the North Yell community and economy. Scotland is recognised as a world leader in wave and tidal energy, with a quarter of Europe's tidal stream and a tenth of its wave-energy potential."