BBC: The largest tidal turbine array in Europe is about to get under way off the coast of the Scottish mainland. MeyGen Ltd plans to build and deploy a fleet of turbines beneath the waves of the Inner Sound of the Pentland Firth. The turbines are to be installed in phases, starting with a demonstration array of six. By the end of the first phase in 2020, 86 turbines could be producing some 86 MW of electricity—enough to power 40% of the homes in the Scottish Highlands. If successful, the company will move on to the second phase, which would see a total of 400 turbines producing about 398 MW of power. While the project site is known for its tidal flow and wave frequency, those same factors, combined with the harsh weather conditions, pose challenges for building and maintaining potentially hundreds of the giant machines.