May's low winds hit capacity factors
Data derived from more than 6,000 turbines with a combined installed capacity of over 11GW revealed that generally low wind speeds across Germany kept overall capacity factors down to 16% during May.
This was the third consecutive month at 16%, after much higher winds in February drove the average capacity factor to a more respectable 30%.
Denmark also saw output drop during May, the 5,000-plus turbines for 5GW of installed capacity reporting to this research recording an average capacity factor of 22% during the month. This was well down on April's average of 28%, and only a little more than half of the 39% recorded in January.
The difference between onshore and offshore wind resources was highlighted by the overall performance of offshore market leader Siemens, whose turbines achieved an average capacity of 32.05% during May, significantly above the company's historic average for May of 29.88%.
Onshore, the best figures were supplied by GE's turbines, which averaged a capacity factor of 17.9% during May, compared with its historic average for the month of 15.8%. Vestas was close behind with nearly 17.2%, but that was below its monthly historic average of 18.2%.
Enercon and Nordex, both of which have specialised in turbines for low-wind conditions, also recorded capacity factors above their historic averages.
Older turbine designs struggled during May, however. NEG Micon's average capacity factor was 13.5%, for example, well down on its historic average of 16.6%. HSW achieved only 10% against its historic average of 13.3%.
Nordex 2.4MW leads onshore
The gap in performance between onshore and offshore turbines is further highlighted when the output of individual turbine types is compared.
Enercon's 2.3MW onshore turbine recorded an average output of 251MWh in May, which equates to a capacity factor of 15%. But Siemens' similarly sized offshore model - an old turbine by offshore standards - averaged 585.5MWh, a capacity factor of 35%.
Interestingly, this was fractionally above the 34% capacity factor of Siemens' newer and more advanced 3.6MW unit, an anomaly that can be explained by the greater number of 2.3MW models in Danish waters, where wind speeds were higher during May.
The outstanding onshore turbines during the month were the 2.4MW Nordex and 3MW Siemens machines, which recorded an average capacity factor of 28% and 26% respectively.