This paper describes how the production matrix of the SEAREV wave energy device is modified by the directional spreading of the wave spectrum and the resulting influence on the annual production at a given test site. A cosine power '2s' function applied to Pierson-Moskowitz spectrum is chosen to model the spreading. The linearized equations of the device, including the motion of the internal pendulum wheel are presented. Numerical results are presented for the power recovered by the device in random sea. Influence of the sea state on the recovered energy was evaluated using an increasing spreading parameter. We show that the results obtained when accounting for the spectrum spreading may be very different from those obtained when considering a mono-directional wave train.