Extended ocean observation missions have been challenging to pursue due to limited energy options and the remote and extreme nature of many oceanic regions. The U.S. Department of Energy has funded the National Renewable Energy Laboratory (NREL) and the Pacific Northwest National Laboratory (PNNL) to explore the energy needs for a set of ocean observation end uses to understand how marine renewables might alleviate some of the challenges associated with operating in the ocean and help to enable expanded observing missions. Consideration for end use applications has been given to a wide range of instrumented observing platforms, including buoys, floats, surface and subsurface autonomous vehicles, gliders, profiling moorings, and seabed observatories. Online surveys as well as phone and in-person interviews were conducted with ocean observing experts and helped inform the choice of marine energy applications, based on end-user requirements, energy needs, and opportunities for co-development. These interviews suggested that there is a strong need for energy systems that can enable longer duration and/or higher payload capabilities than what is currently available. Findings will be presented from a focused set of case studies that are aimed at understanding energy requirements and cost drivers for ocean observing systems powered by marine renewables (wave and tidal energy), as well hybrid solutions that include a combination of marine renewables, wind, solar, diesel, and battery technologies. The case studies have been evaluated in a variety of locations to provide insight into where marine renewables are most appropriate given varying resource limitations, seasonality effects, and end use requirements, such as maintenance intervals, allowable footprint, and power requirements. The choice of end use applications will inform next steps towards development of functional and design requirements for marine energy integration that enables specific ocean observing platforms.