Geospatial Energy Potential and Life Cycle Assessment of Nearshore Oscillating Water Column Systems along the Eastern Coast of New England, United States

Oscillating Water Column (OWC) systems are an iteration of terminator ocean energy technology which generate electrical energy from turbine torque induced by the compression of air in a chamber from changing water level height. OWC systems are a well-established technology, however, there have been no studies to date which quantify the life cycle environmental impacts of these systems in a geographic context. The goal of this study is to optimally size an OWC system for selected coastline sites along the eastern New England, USA coast and then assess the environmental impacts of the varying system sizes.

An OWC system is optimally sized when the volume of its concrete chamber is scaled proportionally to its generation potential; maximizing electrical energy output while minimizing chamber material consumption. Therefore, geospatial variability in generation potential will affect optimized chamber size, in turn, varying the chamber material consumption.

Environmental impacts of the systems were assessed via their contribution to global warming potential due to emissions released at every phase within the life cycle system boundaries from mineral extraction to electricity generation using life cycle assessment (LCA). The functional unit used for the LCA was 1 kWh. A radial geospatial interpolation of wave power and wave period measurements from five Integrated Ocean Observing System buoys was integrated from 2003 to 2017 using monthly timesteps to estimate the coastal generation potential of each OWC system. A sample size of 6,775 shoreline sites returned average generation potentials ranging from a maximum of 6.24 kW m^-1 of wave crest for every 100 km of coastal length to a minimum of 0.31 kW m^-1 of wave crest for every 100 km of coastal length.

This study revealed high variability in estimated energy generation potential over a short geographical span and, therefore, high variability in chamber material consumption between 115.08 m³ - 2132.33 m³ of concrete. These findings emphasize the necessity of quantifying the life cycle climate change impacts of OWC installations prior to design at a national level, as they vary geographically and are influenced by the optimal chamber size and wave power potential.