The foreseen large-scale growth of offshore wind energy towards 2050 in pursuit of an energy transition obliges scholars and policymakers to start considering its integration in the wider offshore energy system. Both technological innovations and advances in spatial policy are necessary to facilitate offshore system integration. This study draws from agenda-setting theory to explore barriers and opportunities affecting the prioritization processes surrounding three offshore energy storage and transport concepts in Dutch marine spatial planning practice. The findings demonstrate that although various arenas for agenda-setting exist, they are geared to the input of established stakeholders, including the oil and gas and offshore wind sectors. Also, prioritization is hindered by a short-term (2030) governmental fixation and long-term institutional ambiguity. Therefore, supportive institutions are needed, providing regulatory certainty and reliable incentive mechanisms, whilst remaining adaptive to address imminent uncertainties, in pursuit of system integration needed for an energy transition.