General Electric's (NYSE:GE) rival Vestas Wind Systems (OTC:VWDRY) announced this week that it is launching the largest offshore wind turbine with its V236-15.0 MW. The "236" refers to the rotor diameter of 236 meters and "15.0" refers to the fact that it can produce 15 megawatts (MW) of power when operating at a normal speed.

The size of the rotor diameter puts it ahead of Siemens Gamesa's SG 14-222 DD offshore wind turbine (no prizes for guessing that it has 14 MW of output power and a rotor diameter of 222 meters) and GE's largest version of its offshore turbine Haliade-X with a rotor diameter of 220 meters and power of 14MW. Size matters because power is related to the area swept in front of it by the blades (pi times the radius squared for those of us who like math).

Offshore wind turbines.

The offshore wind market is heating up. Image source: Getty Images.

That said, output power is one thing and the efficiency with which that can be translated into power in practice is another. GE claims a capacity factor (average power generated divided by peak power) of 60% to 64% for its largest Haliade-X, while Vestas claims a capacity factor over 60 percent "depending on site-specific conditions."

In addition, there are lifetime cost considerations to be made before any decision. It's not simply a case of a larger turbine dominating a smaller one. Furthermore, GE's leadership in digital technology could mean it's better able to offer customers improved service levels by better predicting turbine failures using data analytics.

All told, the new Vestas offshore turbine steps up the competition in an already highly competitive market. GE isn't a significant player in the market as yet, but it's growing its Haliade-X orders as part of its turnaround plans, and it's far too early to count GE out as an also-ran in offshore wind power. 

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