Qualitative validation of empirically observed higher generation in East-West orientated PV arrays over conventional South orientation

Due South has been accepted as the optimal orientation for photovoltaic (PV) power systems in the Northern hemisphere by convention. It is assumed that over a year maximum energy collection occurs in a fixed PV system when it is mounted at a tilt angle equal to the latitude of the location facing due South orientation. However, it has been observed that some systems perform better at orientations other than due South and latitude tilt. It has been practically observed in a full scale roof-top PV installation that there is a considerable gain, as high as 6 %, in specific annual energy generation (kWh/kW) in power plants with a combination of East and West facing modules over a plant with conventional South facing modules alone. This paper analyses the data gathered from this system over an entire year and discusses the observations drawn on the system performance. Effect of different variables like season, declination of the sun, time of day, weather pattern of the location & configuration of the strings on the energy generation are studied in this paper. The system under study consists of three East-West facing PV power plants and one South facing power plant.