Sustainable Energy

Supersized Wind Turbines Head Out to Sea

The giant turbines could help make offshore wind cheaper.

Feb 1, 2013

Siemens installed two colossal offshore wind turbines this week, demonstrating technology that could have a significant impact on the economics of wind power.

The ships designed to install conventional offshore wind turbines weren’t big enough for Siemens’s newest turbines, so it had a new ship built for the job. The smokestack-like tubes are stilts that lift the ship out of the sea to steady it and allow the turbine to be installed.

The vessel shown here, the Sea Installer, is 132 meters long and has a loading capacity of 5,000 metric tons—enough for 10 wind turbines.

The nacelles, which house the wind turbine’s generator, are 15 meters long.

These six-megawatt turbines will eventually use three 75-meter blades, which will be bolted together, one by one, at sea. The first two turbines will use shorter, 60-meter blades, which can be added on shore.

A close-up of the blades gives a better sense of their scale.

A turbine nacelle is lowered onto a tower that’s been anchored in 13-meter-deep water off the southeast British coast. The Sea Installer can handle depths up to 45 meters.

The ship can be seen here hoisted above the water, the installation complete.

The German company has been developing the turbines, which produce double the maximum power output of its current models, for several years. It has been testing the technology on land, and installed the first ones offshore with the help of a new ship designed specifically for the task. The turbines feature test blades that are 60 meters long, but Siemens intends to employ world-record 75-meter blades eventually.

Yet for offshore wind power to compete with fossil fuels, wind turbines may need to get even bigger. The new turbines generate six megawatts of power in good wind. Several companies are designing 10- and even 15-megawatt machines with 100-meter blades. These blades would reach two-thirds of the way to the roof of the Empire State Building. The push to supersize wind turbines is part of an effort to reduce installation and maintenance costs, which can be far higher than the cost of the turbines themselves. The pictures in this slideshow give a sense of just why installation is so costly.