The aim of this paper is to show some design improvements on converters oscillating water column (OWC) versus conventional OWC, focusing on a newly patented design, OWC with Differential Pressure Storage Tanks (DPST). In this research work, a short review of the principles of operation and the results obtained for each one in relation to energy efficiency and regularity of electricity delivered to the grid are described. Apart some known innovations published so far in scientific journals, it will be discussed in more detail a new design (protected by patent) that tries to overcome some major performance problems in both conventional and improved OWC proposed up today such as intermittent flow through the turbine and the bi-directional flow. It is concluded that there are feasible to implement innovations that can lead to improvements with respect to OWC currently in operation