Maschinen- und Anlagenbau Nautilus, which supplies aluminium panels and steel components, is to close its plant in the port of Emden on 30 June.
Uncertainty created by Germany's shift to an auction system has resulted in fewer long-term orders for suppliers.
Enercon is also switching to glass fibre-reinforced plastic panels to reduce costs, a spokesman explained.
Meanwhile, in Zurndorf, Windenergiekomponentenfertigung Austria, which exclusively supplies Enercon with pre-fabricated concrete tower segments for the German and Austrian markets, will cease production on 27 April before closing the works.
The order volume in both countries is massively reduced, transport logistics prevent export of the tower segments, and local content requirements in other countries necessitate production elsewhere, Enercon explained.
The moves follow closure of Enercon supplier and blade manufacturer Rotorblattfertigung Magdeburg (ROMA) and of Austrian installation unit Enercon Service Austria and its dependent units at the end of 2017.