Geospatial Energy Potential and Life Cycle Assessment of Nearshore
Oscillating Water Column Systems Along the Eastern Coast of New England,
United States
Abstract
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 m^3 - 2132.33 m^3 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.