Offshore wind and ocean health: navigating sustainable growth

Wind energy is a key pillar in the UK Government’s decarbonisation targets. It has a goal to quadruple the UK’s offshore wind capacity by 2030 and has committed, through Great British Energy and the Crown Estate, to cut the time it takes to build new wind farms. The goal is to help unlock 20-30GW of offshore wind seabed leases by 2030. 

These are big targets with big stakes, not least how this can be done sustainably. 

ECOWind and ECOFlow

How we do this – how we expand offshore wind infrastructure while ensuring the protection and health of marine ecosystems, in a context of climate change – is the focus of two, multi-year, multidisciplinary programmes involving science and research organisations across the UK, including the National Oceanography Centre (NOC). 

Progress on these programmes, ECOWind (a four-year programme, now two years in) and ECOFlow (launched early November – Flow standing for floating offshore wind), was discussed at their annual impact meeting, held in Southampton, last week (November 20-21). 

The event delved into a number of the programmes’ projects, from how wind farm wake effects impact ocean stratification – and therefore productivity of plankton, the basis of the marine food web – to the impact of marine spatial planning on feeding grounds for key seabird species. 

It also covered how vibration, from piling operations during offshore wind farm construction to operation vibrations, affects hermit crabs, and how having new substrate to colonise impacts ecosystems and ecosystem functions.

_{An infographic showing the ECOWind ACCELERATE project.}  

How much seabed is lost due to offshore wind farm construction and how much new substrate is created, and how this can increase habitat and species abundance – but not necessarily species diversity or health – was also discussed. 

Critically, how we model not just what the past and present impacts are, but also what the future impacts will be and how we can adapt policy to mitigate or even help benefit ocean health, was also a strong theme at the event across the programmes. 

NOC is playing a significant role across nearly all of the ECOWind projects, applying our multidisciplinary expertise. Multiple projects within ECOWind are underpinned by our oceanographic models. Several are enabled by our Marine Autonomous Robotic Systems (MARS) capability. We’re also bringing to ecosystem expertise, including benthic (seabed) ecosystems, to multiple ECOWInd projects. 

_{Seabed images taken as part of the ECOWind ACCELERATE project, credit: ECOWind-ACCELERATE/Bangor University. *See full caption at the end of the blog.}  

ECOWind ACCELERATE - benthic habitats

During the event, Dr Lisa Skein, a benthic ecologist, outlined her work as part of the ECOWind ACCELERATE project looking at how species distribution could change as a result of both climate change and offshore wind farm development. 

This is work that involves looking at 19,000 seabed images to help characterise all the different seabed habitats in areas where some offshore windfarms are already operational, and where more will be installed in the near future. And there are many different habitats, even just in the Eastern Irish Sea study area this project is focusing on. 

Characterizing the benthic (seabed) communities across the different habitat types is the first step toward modelling how these communities could respond to climate change, in combination with other environmental changes resulting from wind farm installations. 

_{Bangor University's RV Prince Madog was used for the ECOWind ACCELERATE project.}

_{The epibenthic camera sled used for the ECOWind ACCELERATE project on the deck of the RV Prince Madog.}

PELAgIO - North Sea mixing and stratification

Dr Michela De Dominicis talked about her work on the PELAgIO project, which is focusing on using ocean computer simulations to understand how new offshore wind farms could affect the balance between mixing and stratification (the different layers in the ocean) in the North Sea, focusing on the Firth of Forth, offshore Scotland. 

This hasn’t been so much of an issue so far, because most wind farms to date have been built in shallower waters where the water column is mostly fully mixed throughout the year. 

As offshore wind development moves into deeper waters, they can alter the delicate balance between stratification and mixing, which supports the life cycle of plankton, which is the base of the food chain that supports fish, seabirds and big marine mammals.

Altering the mixing and stratification in a sea like the North Sea can potentially lead to changes in the behaviour of the fish, seabirds and marine mammals in these seas.

Observations made to date will help Dr De Dominicis build and refine ocean computer simulations that will help us predict these impacts and how they interact with impacts from climate change. 

_{Ocean gliders used on the PELAgIO project.} 

Read more about how we’re using gliders on the PELAgIO project here. 

The event also heard about work by NOC scientists Dr Julia Rulent and Dr Lucy Bricheno on the effects of climate change, primarily sea level rise and changing storminess, on the seabed – and the organisms that it supports (and even carbon storage within seabed sediments). 

The results from these projects, combining how climate, offshore wind expansion and human activity in the ocean currently do and could impact its health in the future, are important for ensuring offshore wind deployment is supported by science. 

They are important to provide better decision support for policy and practice.

*Collection of seabed images, description: Images from some camera stations and a collection of the typical habitats surveyed during the June 2024 ECOWind-ACCELERATE Prince Madog cruise. Station C4 and E4 gives a typical depiction of natural rocky substrata in the study area, where preliminary analyses show epifaunal diversity to be greatest. Also depicted at Station E4 are substantial quantities of Modiolus modiolus mussel shells that can have a big influence on physical habitat complexity. Typical pebble/cobble habitats are shown for stations G6 and H9, which in general have been found to support the higher densities of epifauna, but that are not as diverse as those found in rocky habitats. Stations H5 and I1B were typical of mixed sediment habitats with varying quantities of small rocks, pebbles and gravel and characterised by mix of hard- and soft substrata fauna such as bryozoans, starfish, anemones and hermit crabs.