The bottlenecks which could constrain emission cuts

AT 107 METRES, the three carbon-fibre blades of a Haliade-X marine wind turbine are longer than the wingspan of any airliner ever made. The generator which transforms their rotation—over 300km an hour at the tip—into power requires over 100 powerful magnets made of exotic metals and untold lengths of coiled-up copper. The blades, generator and associated gubbins, weighing around 900 tonnes all-in, have to be installed on a pylon so tall that the blade-tips reach almost as high above the waves as the pinnacle of the Transamerica Pyramid rises over the 600 block of San Francisco’s Montgomery Street.