Vestas’ new way of handling wind turbine blades squeezes a world-record nine complete turbines onto the deck of the MV Resolution, cutting from 17 to just 12 the number of trips needed to install the 100 Thanet turbines. But that’s not the only productivity increase on this project, explains Vestas offshore engineer Adrian Botwright. By letting crews install blades safely in higher wind speeds, the new system means less time spent waiting for the weather.
“Competitive wind power needs a ‘production-line’ approach, and in future that will mean working through the winter, as we have done at Thanet,” he says. On previous Vestas projects, each nacelle left the quayside with two blades attached. This “bunny ears” arrangement took up a lot of quay and deck space, and required the third blade to hang vertically as it was lifted into position, leaving it vulnerable to gusts of wind.
At Thanet, however, a special new gripper keeps blades balanced in the horizontal position as they are lifted, allowing installation crews to work safely in higher wind speeds. They install the bare nacelle first, and then add the blades one at a time. To carry individual blades aboard the Resolution Vestas engineers have devised a steel cradle that carries six blades one above the other. “Not only that, but when we are loading the ship we can lift three blades together. When loading 27 blades for each trip it is important to reduce the number of lifts.” Botwright says.