The bigger the better.

That seems to be the mantra right now in the competition among major wind turbine manufacturers.

Last week, Chinese manufacturer Dongfang installed the first ever 18MW offshore wind turbine with a diameter of 260 meters and potentially capable of producing 72 gigawatt hours per year.

On Tuesday, Siemens Energy has joined the competition. According to Bloomberg News, the wind turbine manufacturer has told customers that it plans to build its largest turbine to date - probably by the end of this decade - capable of producing 21MW, according to sources.

The planned turbine is about 40% more powerful than the company’s other turbines, the largest of which has a wingspan of 115 meters.

The move can be seen as a reignition of the race among Western manufacturers to produce the large turbines. Development work has been put on hold in recent years as the wind industry has lost money and supply chains have been under pressure.

But the race is also on in China, where other Chinese manufacturers than Dongfang, such as Mingyang, are also aiming to develop mega turbines.

Last year, the EU channeled EUR 30m to Siemens Gamesa to test what was called ”the world’s most powerful wind turbine prototype” at the Test Centre Østerild in Denmark. However, no details were given on either size or timeframe.

Vestas’ largest turbine, the V236 15MW, also has a diameter of 236 meters and can deliver 80 gigawatt hours per year.

English edit by Kristoffer Grønbæk