Oscillating Water Column (OWC) wave power device is one of the most pioneering devices in terms of hydrodynamic efficiency. An OWC with two parallel walls (called harbour walls) extracts more power for a wider frequency band width. Literature evidence shows that the MOWC in array are more efficient rather than an isolated device. The array acts as a perforated breakwater which absorbs wave energy. Besides absorbing energy, remaining waves get dissipation and reflection. The array protects the shore from beach erosion, sediment control due to rough sea waves. An experimental study using method of images shows that an array spacing of three times the OWC width extracts more power. The array is subjected to breaking, broken and non-breaking waves. The wave - structure interaction at the end of the array needs particular analysis. Since, at the end or corner point, the dynamic action of waves produces vortex shedding, turbulence, etc. Hence, the wave power absorption for the corner caisson will be different from that of the other caissons. This anomaly can be said as the end effect. The hydrodynamic stability of such corner device also needs to be studied. Over topping effect needs to be studied. The engineering design aspects of such an array need several parametrical investigations in addition to cost-benefit analysis. Several design aspects are to be explored, before venturing to commercial developments. This paper features on the present status, the need for new developments and the problems ahead for prototype development.