Revenue at Senvion fell 18% to €479.9m in the third quarter of 2017, down from €584.3m in the same period last year.
The German manufacturer said the drop was down to a decline in offshore and Canadian onshore revenues.
The revenue fall impacted earnings, with adjusted EBITDA of €41.4m in the quarter, compared with €60m last year.
In the first nine months of 2017, Senvion reported revenue of just over €1.3bn, a drop of 10% on the more than €1.45bn posted last year.
Adjusted EBIDTA was also down in the first three quarters of 2017 to €103.1m from €132.3m in 2016.
Senvion said it had experienced a “slowdown in established markets”, such as Germany, in the third quarter that had impacted the order book.
However, the order intake had increased by 51% over the first nine months of the year to €5.3bn, compared with 2016, the company said.
Senvion chief executive Jürgen Geissinger said: “Senvion’s performance for the first nine months is in line with our guidance.
“Our year to date order intake has been strong despite worsening industry dynamics.”