The 1 MW tidal turbine will power a computer data center and is 75 feet high and weighs 1430 tons. The blades move slowly, so there should be no danger to aquatic life. This is a commercial application, not a test. While 1 MW is small compared to wind turbines (some offshore turbines can generate 10 MW) this is a big step forward for the developing technology of tidal turbines.
More from the BBC.