Potential Environmental Effects of Marine Renewable Energy Development—The State of the Science

Abstract

Marine renewable energy (MRE) harnesses energy from the ocean and provides a low-carbon sustainable energy source for national grids and remote uses. The international MRE industry is in the early stages of development, focused largely on tidal and riverine turbines, and wave energy converters (WECs), to harness energy from tides, rivers, and waves, respectively. Although MRE supports climate change mitigation, there are concerns that MRE devices and systems could affect portions of the marine and river environments. The greatest concern for tidal and river turbines is the potential for animals to be injured or killed by collision with rotating blades. Other risks associated with MRE device operation include the potential for turbines and WECs to cause disruption from underwater noise emissions, generation of electromagnetic fields, changes in benthic and pelagic habitats, changes in oceanographic processes, and entanglement of large marine animals. The accumulated knowledge of interactions of MRE devices with animals and habitats to date is summarized here, along with a discussion of preferred management methods for encouraging MRE development in an environmentally responsible manner. As there are few devices in the water, understanding is gained largely from examining one to three MRE devices. This information indicates that there will be no significant effects on marine animals and habitats due to underwater noise from MRE devices or emissions of electromagnetic fields from cables, nor changes in benthic and pelagic habitats, or oceanographic systems. Ongoing research to understand potential collision risk of animals with turbine blades still shows significant uncertainty. There has been no significant field research undertaken on entanglement of large animals with mooring lines and cables associated with MRE devices.

The Use of Animal-Borne Biologging and Telemetry Data to Quantify Spatial Overlap of Wildlife with Marine Renewables

“…The potential adverse effects of marine renewable energy devices on marine wildlife, for example the risk of underwater collision with tidal turbines, remain uncertain [5]. In addition, the need to assess the magnitude of any effects and adopt a precautionary approach is likely to delay or even prevent developments where empirical measurements of overlap between animals and sites are lacking.…”

“…Marine renewables (fixed and floating offshore wind; wave; and tidal energy) have been identified as key to the transition to net-zero emissions [1,2]. In order for consenting decisions for marine renewable energy developments to be made responsibly, any potential negative impacts on key ecological receptors (birds, fish, marine mammals, turtles) need to be assessed [3][4][5]. A key constraint for marine renewables is understanding how animals use development sites, and the risk of collision that they may be exposed to [5][6][7][8].…”

“…In order for consenting decisions for marine renewable energy developments to be made responsibly, any potential negative impacts on key ecological receptors (birds, fish, marine mammals, turtles) need to be assessed [3][4][5]. A key constraint for marine renewables is understanding how animals use development sites, and the risk of collision that they may be exposed to [5][6][7][8]. Taking tidal energy as an example, fatal collision with dynamic parts of operating devices (e.g., rotating blades) has been identified as a major concern for marine vertebrates [5,7].…”

“…A key constraint for marine renewables is understanding how animals use development sites, and the risk of collision that they may be exposed to [5][6][7][8]. Taking tidal energy as an example, fatal collision with dynamic parts of operating devices (e.g., rotating blades) has been identified as a major concern for marine vertebrates [5,7]. Due to the small number of operational tidal turbines in the water worldwide, de-tecting collision events, or the absence thereof, remains challenging [3].…”

“…Where such information is lacking, an alternative is to quantify space use of animals in tidal stream environments [9][10][11]. Assessing spatial overlap of these areas with areas in which turbines are likely to occur, that is tidal energy development sites, can then inform about the level of risk to wildlife [5,12,13]. Any connectivity with renewable energy developments will then not only identify populations at risk of exposure but also inform the need for and extent of any additional research.…”