Mobile communication networks are experiencing an important evolution, with the emerging deployment of 5G networks and the successive decay in the usage of previous generations in next years. In parallel, policies promoting an ecological transition gain social impact and economic interest. In the telecommunications market, the shift between two dominant generations could be an important chance to introduce renewable energy sources in an attempt to greening the sector. This work analyses the current situation and provides insight on the possibilities to incorporate renewable energy supplies, concretely photovoltaics (as it seems to be the most promising among clean electric sources), also comparing the characteristics of standard facilities in two different European countries as Spain and Poland.