We report on an advanced modelling approach to accurately predict the energy yield of custom environment / urban integrated photovoltaic systems (E/UIPV). Several sub-models are here presented and their mutual interaction discussed. The flexibility of our software platform allows to exhaustively simulate custom horizons in combination with rigid/flexible PV modules and in presence of albedo component. In this respect, a modelling example predicts AC-side yield with < 1% error on annual basis with respect to actual data. In addition, our platform can also deal with coloured / bifacial modules and soiling losses for PV energy yield potential or performance prediction.