Danish renewable energy company Greentech has sold its half of a northern Poland wind farm project to local partner PGE because the stake would not give it control of the project.

Greentech's exit from the 28 megawatt Wojciechowo wind farm project for 3.6 million euros ($4.8 million) comes at a time when uncertainty over a new renewables law has forced other companies in the sector to suspend their projects in Poland.

France's EDF and Finland's Fortum recently both froze Polish energy investments, and Spain's Iberdrols and Denmark's DONG Energy also plan to sell their renewable units in Poland.

Greentech chairman Peter Hoestgaard-Jensen said in a statement issued late on Thursday his firm was leaving the project because a 50 percent stake did not give it sufficient influence over the project.

He said Greentech will continue to invest in Polish renewable energy and had projects under development there with a capacity of more than 260 MW.

Poland, which generates around 90 percent of its electricity from coal, has been working for months on a new renewable law. Uncertainty over when the regulations will be implemented has discouraged banks from financing new projects.

The country has around 2,500 MW of installed wind energy, representing more than 5 percent of the power system's total capacity. Under EU law at least 15 percent of Poland's energy production must come from renewable sources by 2020. ($1 = 0.7477 euros)