As of the end of 2008, REWE Group had started operation of photovoltaic systems on the roofs of the first four logistics locations. The systems have been installed on the roofs of the warehouses in Eitting, Buttenheim, Rüsseina and Hildesheim and have a total output of 3,640 kWpeak. Peak stands for the maximum output which can be achieved under ideal conditions, e.g. brilliantly blue skies and outside temperatures which are not too high.
Various techniques are used in photovoltaic modules. A distinction is made between monocrystalline, polycrystalline and amorphous modules. Amorphous modules have a lower degree of efficacy. The amorphous modules installed at the warehouse locations in Buttenheim and Hildesheim have a specific output of 63 Wp/m². The polycrystalline modules used in Etting provide 149 Wp/m², and those in Rüsseina provide 131 Wp/m².
In addition, further photovoltaic systems began operation in 2009 on the roofs of the warehouse locations in Eching, Großbeeren, Neuhausen, Halle and Rostock-Roggentin.