This paper presents a parametric study on arrays of wave energy converters (WECs). Its goal is to assess the influence of interactions between bodies on the overall yearly energy production of the array. Generic WECs (heaving cylinder and surging barge) are considered. Nine to twenty-five WECs are installed along regular square and triangular grids; the influence of the separating distance between the WECs is investigated. Results show that constructive and destructive interactions compensate each other over the considered range of wave periods. The influence of the separating distance can be limited, especially if the damping of the power take-off is tuned properly, and if the WECs have a large bandwidth. It is found that grouping the devices into arrays have generally a constructive effect. Diffracted and radiated waves in the array lead to a sufficient increase in the energy absorption which overcomes the reduction due to masking effects.