WARSAW - Poland's state-owned utility Energa and state-controlled lignite miner Adamow inked a deal to build windfarms with a total output of 80 megawatts, Energa said on Thursday.

The windfarms, planned at initial capacity of 40 megawatts of power in 2012, will be built on grounds no longer used by the open cast lignite mine.

The investment will allow us to acquire another source of renewable energy and increase its share in Poland's energy balance, Energa's chief executive Miroslaw Bielinski said in the statement.

The firms did not say how much they will spend on the farms.

Poland depends on heavily polluting coal for more than 90 percent of its energy needs. Renewable energy sources account for some 7 percent of its power production with wind plants providing some 550 megawatts in mid-2009.

Due to natural conditions wind power is considered the most viable alternative renewable energy source in Poland and most of the green energy is expected to be generated from this source.

(Reporting by Patryk Wasilewski; Editing by Keiron Henderson)