Global energy strategy has quickly shifted to a new paradigm. Countries understand the importance of a near-zero carbon energy mix and the need to reduce their energy imports and become energy independent. One immediate solution is the re-enforcement of renewable energy infrastructures such as wind, solar and hydro generation. However, certain sectors, particularly the Blue Economy, may need a different solution. The oscillating-water-column (OWC) wave energy converter is a proven concept, many prototypes of which are already being deployed on the open sea, and can help bridge this gap. Energy harvesting from this system will be improved if more efficient (and reliable) power take-off (PTO) systems and control algorithms are used. A novel control algorithm for a turbine–generator set was developed based on the physical interactions between the PTO and the OWC system. The results were compared with experimental data from real operation at sea. The algorithm does not need to predict the sea state conditions in order to maximise power generation. Additionally, it protects the PTO in extremely energetic sea states and minimises overspeeding and the use of a safety valve. Comparing the operating results of the 30 kW biradial turbine–generator set at the Mutriku wave power plant with the corresponding numerical results provided by the novel control algorithm showed a 6% increase in annual electricity production.