Revenue fell 13.7% from €2.56 billion to €2.2 billion this year. Similarly, EBITDA totalled €398 million in Q2, down 23.9% from a year earlier, and profit from the period was recorded at €186 million, down from €278 million in 2016.
Vestas said the fall in earnings was due to an exceptional period in 2016, which included the 1GW order from Statkraft for the Fosen cluster of projects in Norway.
The company's H1 results were "on par" with 2016, the company said. Revenue for the first six months of 2017 increased slightly from €4.02 billion to €4.09 billion.
First half EBITDA was practically level while profit for the period totalled €346 million, up 10% from €313 million, the company said.
The outlook for the rest of the year remains positive for Vestas however. Order intake for Q2 totalled 2,667MW, the firm said, up from 1,790MW last year.
The increase was driven by a strong showing in China, where orders were three times higher than last year, totalling 298MW. Vestas also performed well in the US, with 924MW in orders during the quarter, and a further 374MW from Argentina.
At the end of June 2017, Vestas order backlog amounted to almost 10.7GW.
As part of its financial results, Vestas announced a DKK 4.46 billion (€600 million) share buy-back programme in order to "adjust the capital structure" of Vestas. The manufacturer launched a similar programme after Q2 last year and Q3 in 2015.
Outlook for the year remains unchanged, Vestas said. It still predicts revenue to reach between €9.25 billion and €10.25 billion.