#WorldsLargest - The world's most powerful tidal energy turbine writes the BBC News was assembled at Harland and Wolff shipyard in Belfast.
One of the yard's cranes, Goliath, will lower the 520-tonne structure into Belfast Lough today, Wednesday.
Each of the its twin rotor arms produces 1 megawatt of energy - enough to power thousands of homes when connected to the electricity grid.
After trials in the lough, the turbine will be used off the Orkney Islands.
The 75-metre long structure has taken a year to put together.
It will float on the water with the rotors dropped below the surface.