RWE Energie is also carrying out a study of the wind potential in its supply area, to apparently overlap with the recently completed resource study for North Rhine Westfalia carried out by Münster University. RWE Energie may find some promising wind sites on the 80 metre high artificial hills created by the dumping of overburden from opencast lignite mining. RWE Energie's sister company, Rheinbraun, annually mines over 100 million tonnes of lignite in North Rhine Westfalia. RWE stresses that any new technology must be able to produce power for just DEM 0.04/kWh, the average cost of production across the utility's existing collection of conventional and nuclear power stations. However, it might consider initiating wind stations elsewhere in Europe or the world, possibly in co-operation with other utilities such as the Italian ENEL.