In May, EnBW announced it had made an offer to buy the insolvent firm in an all-cash deal.
The lead creditors had made the EnBW offer its preferred bid. However, at a creditors meeting in Germany last night, members voted in favour of a cooperative model in a bid to change the company's fortunes themselves.
EnBW CEO Frank Mastiaux said: "We regret this decision because Prokon and EnBW would have fitted well together to jointly promote wind power in Germany. But we also have great respect for the solidarity expressed by the Prokon unitholders."
In January 2014, Prokon filed for insolvency following the withdrawal of capital by a number of investors.
Prokon has a project portfolio of 537MW in Germany and Poland, and even developed its own 3MW turbine in 2013. It is planning a further 4.2GW of wind projects in Germany, Poland and Finland.
In 2013, EnBW unveiled a "2020 strategy" to invest €3.5 billion in renewable energy and expand the portfolio to 40% of its business, up from 12%. Mastiaux said the strategy remains unchanged by today's decision from Prokon.