The manufacturer is "suffering significant losses for the first time", managing director Hans-Dieter Kettwig said.
Onshore wind installations in Germany in the first half of 2019 were 87% below the average level of the previous three years, according to a report by agency Windenergie an Land.
Enercon said its own installation rate has sunk to a 30-year low, installing just 210MW in the first ten months of 2019.
It has now ended cooperation with "several domestic production partners", including producers of rotor blades and "other components" in Aurich and Magdeburg, the firm stated.
Enercon is also "significantly reducing planning for 2020", and plans to focus on international markets, "adapt company structures" and freeze recruitment as part of a company-wide cost-reduction programme.
Enercon blamed the introduction of tenders and "failed political reforms" for the collapse of Germany’s onshore wind market, and stated that orders had "ground to a halt".
It added that the recently passed climate protection package entrenches problems facing the wind power industry in Germany and creates new, bigger challenges.
"The cost pressure is immense," added Jost Backhaus, a member of Enercon’s management team. "We are up against tough competition from major global companies."