MASTS Open Forum Session: Anthropogenic Energy in the Marine Environment

The MASTS Numerical & Experimental Hydrodynamic Modelling (NEHM) Forum is excited to host this free Open Forum Session with several interesting talks:

Energy Pollution by Offshore Wind Farms
Speaker: Dr Rory O’Hara Murray (NEHM Forum Convenor; Scottish Government)

Offshore wind farms are becoming increasingly ubiquitous in our shelf seas. The recent ScotWind leasing round has set the scene for development in deeper North Sea waters. These deeper (>60 m) shelf seas are less dynamic than the shallower nearshore environment and undergo seasonal stratification, which in turn triggers the development of fronts, the spring plankton bloom, and enhances primary productivity across the shelf seas. Offshore wind farms structures could enhance vertical mixing though turbulence production, which has the potential to change shelf sea stratification. This brief introduction will set the scene for the open forum session exploring anthropogenic energy in the marine environment.

Energy Pollution by Ships
Speaker: Dr Momchil Terziev (NEHM Forum Steering Group; University of Strathclyde)

Ships interact with the marine environment in a variety of ways including physical and chemical pollution. While chemical pollution is understood and increasingly regulated, the physical effects of the injected energy resulting from ship operation is not understood well. Energy pollution by ships includes the production of waves and injection of turbulence which may persist for regionally relevant timescales. This turbulence has been shown to mix layers of the ocean, affecting the natural pycnocline alongside inducing mortality in micro and macro organisms. This talk will summarise existing evidence and research of energy pollution by ships and discuss current approaches to modelling the phenomenon and related challenges.

Improving tidal energy capture by a partial-width array using Flow Alteration by Introduced Roughness (FLAIR)
Speaker: Dr David Woolf (NEHM Forum Steering Group; Heriot-Watt University)

The most efficient means of harnessing power from a current in a channel (e.g. tidal stream) is by a “tidal fence” across the entire width of the channel. However, that is almost always impractical and therefore various array designs that leave “gaps” are proposed. Currents tend to avoid the turbines and pass through the gaps reducing efficiency. Array efficiency can be improved by obstructing flow through the gaps. To maintain navigation and migration, obstruction by roughening the seabed is the most likely option; this leads to “FLAIR” as a concept. The physical concept is quite simple, the practical and social parts are far more difficult! Roughening can be in the form of large solid objects or debris such as concrete or scrap metal, or can be through deliberate cultivation of seabed flora such as kelp.  In either case, the approach may be antagonistic to conservation legislation, though in one sense this is perverse since without FLAIR the flow in the gaps (and therefore, “the environment”) will be altered by the array. Suggestions are welcome.