Want, Andrew, Waldman, Simon, Burrows, Michael T, Side, Jonathan C, Venugopal, Vengatesan, Bell, Michael C. 2024. Predicted ecological consequences of wave energy extraction and climate-related changes in wave exposure on rocky shore communities, ICES Journal of Marine Science, 81, 7 (1263–1281). https://doi.org/10.1093/icesjms/fsae086
Waving Hello
Wave energy shows a lot of promise in helping the world phase out fossil fuels. The technology continues to be perfected while sites along high energy coastlines are mapped out. The west coast of the UK exposed to the Atlantic Ocean is a prime candidate with testing already being performed here.
Attenuators are offshore converters currently being used. They resemble segmented snakes that float on the surface, running perpendicular to the incoming waves. As a wave passes, each segment rises and falls, generating electricity.
However, the impacts of this infrastructure on the ocean itself is not well assessed. So far, much of these analyses use prior studies from offshore wind farms. This certainly can give an idea on how the local ecosystem may react regarding anchoring of the structures to the seabed. Yet, this ignores arguably the largest impact wave converters will have; a decrease of wave height on the shore.
This is important because these high energy systems heavily influence the biological community on rocky shores. Waves create a gradient of organisms both horizontally and vertically across the shore line based on their tolerance to the wave action. If the wave height reaching the shore is changed permanently, this can have cascading effects on the community, forever altering it. The question now is, is wave energy worth the risk in order to combat climate change?
Researchers set out to predict how rocky shore communities would change if wave energy converters were installed on the west coast of the Orkney islands, north of Scotland. Not only that, but compare the scenario to how the shore would change under predicted climate change scenarios with increasing wave energy in the next 25 years.
Either Or
Three scenarios were assessed.
- Energy Extraction (EE)
- Energy converters are installed along the coast
- Climate Change (CC)
- Climate change increases the wave energy
- Energy Extraction + Climate Change (EE + CC)
- Energy converters are installed and climate change increases the wave action
Each scenario demonstrated varied impacts across the shores assessed and the organisms present. This is best demonstrated by figure 1 which quantifies the risk of change in abundance for studied organisms. The larger the bar, the greater risk of change. Overall, Energy Extraction had the least predicted amount of change in abundance while Climate Change had the most.
Worth the risk?
Installing wave energy converters along the west coast of the UK would undoubtedly change the wave height reaching the shore and therefore the biological community present. However, researchers showed that climate change would have significantly more impact. It seems that installing the converters is the lesser of two evils with the combination of Energy Extraction + Climate Change only having moderate impacts on the coast.
These results are dependent on the accuracy of climate models and how wave height will change as the climate does. Yet, this information helps provide a baseline analysis of wave energy converters on rocky shore ecosystems. This is an important tool for marine management to make informed decisions to find the best of both worlds. Further research can build upon this model to make it more accurate and help make informed decisions on how we can deploy this wave technology to help decarbonize the energy industry.
I am a recent MSc graduate in marine biology from Bangor University, where I studied population dynamics of elasmobranchs off the coast of Wales. My interests lie in ecological data analysis to understand environmental processes and identify natural patterns. However, nothing beats being in the field and interacting directly with the marine life.
