The booming business of knitting together the world’s electricity grids

IMAGINE, IF YOU will, a toy boat that might fit in the palm of your hand. At mid-ship add a squat spool of sewing thread lying on its side. Scale that up about a thousand-fold and the result is the 150-metre-long . The thread in question is kilometres of high-voltage power line ready to be deployed from the aft of the ship across the sea floor. Each cable, weighing a hefty 150kg per metre and thick as a tree trunk, is a woven mix of aluminium, steel, lead and insulating material. The single stretch loaded up in a bobbin nearly 30 metres across is as heavy as the Eiffel Tower.