In 2022 the Crown Estate identified potential Areas of Search for Floating Offshore WindFarms (FLOW) in the Celtic Sea with the goal of unlocking 4GW within this region by 2035, enough to power 4 million homes.
Whilst the Celtic Sea offers good wind resource opportunities, favourable seabed, water depths and proximity to population centres, there are a multitude of environmental and human use constraints on where FLOW can be successfully developed.
A key constraint is that of shipping and navigation, our analysis identifies the following attributes of key commercial vessel activity:·
- vessels into Bristol Channel: More than 2,500 per year
- vessels using the Traffic Separation Scheme North and South: More than 9,000 per year
- vessels entering Milford Haven: More than 1,000 per year
Having worked on numerous floating projects in and around the region, (including Erebus, Gwynt Glas and White Cross), and through our recent work with the ORE Catapult Floating Offshore Wind Centre of Excellence, we have identified 6 challenges that developers will need to consider and overcome in the Celtic Sea.
Challenge 1. The need for wet storage areas
The construction and maintenance of fixed foundation offshore wind farms hasn’t typically significantly impacted inshore vessel traffic, ship anchorages or port approaches.
However, being such large structures, there’s limited space in ports and harbours to meet all the requirements of large scale commercial floating offshore wind farms.
It may also prove inefficient to fully assemble each floating offshore wind turbine and tow them to site individually. Similarly, there may be a need to conduct O&M activities in more sheltered locations than within the array area offshore.
There’s therefore a likely need to marshal and temporarily moor floating structures during construction and O&M phases.
Challenge
Wet storage areas are likely to be in locations favoured by other activities, sheltered waters, near to ports with depths suitable for anchorages and in areas transited by recreational or fishing vessels. Just like the array area, they will need to be clear of shipping routes and other activities.
The multitude of Celtic Sea projects will drive greater demand potentially resulting in greater congestion and conflicts in these sensitive locations.
Without wet storage locations being adequately defined at an early project stage, the consideration of these impacts may be omitted from assessment in EIAs and their supporting Navigation Risk Assessments.
Solution
Ensuring wet storage sites are properly planned, risk assessed and managed at an early stage will be crucial to the success of commercial scale FLOW projects.
Sites should be planned clear of key maritime constraints, all hazards appropriately identified, assessed, and suitable risk control mitigations implemented.
This will likely necessitate new guidance and additional studies.
Challenge 2. Impacts on nationally important ports
The number and scale of proposed floating projects introduces new risks both around project sites and within ports and harbour areas and approaches.
Towage of floating structures through these areas and other project traffic during construction and O&M is likely to increase interactions with other vessels which may not only increase risk but also impact port capacities and operations.
Challenge
Floating offshore wind places greater demand for ports during construction and O&M. These might include impacts on port capacity, infrastructure and safety which need to properly assessed.
As there are nationally critical ports in the region such as Milford Haven, Port Talbot and Bristol amongst others, developers will need to be mindful to safeguard significant routes and activities.
Solution
Ports and harbours need to prepare for these activities, working with developers to ensure that the appropriate infrastructure, risk assessments and controls are in place to manage these activities safely.
Challenge 3. FLOW Towage
FLOW platforms are inherently mobile assets and the greater movement of them will increase the range of impacts that a project has.
Platforms will be towed to/from the array area, construction base or wet storage sites and may encounter other traffic or activities whilst on route.
A 2021 study determined that no ports in Wales have the capability to deliver all required functions for FLOW construction (Catapult, 2021). Within the study, an example strategy consisted of:
• Substructure Assembly: Port Talbot and Pembroke Port.
• Mooring Line and Anchor Assembly: Port Talbot.
• Wet Storage: Milford Haven.
• Turbine Assembly: Pembroke Port.
This would involve increased movements backwards and forwards between different ports/harbours and array areas. The density of vessel traffic in the Celtic Sea and limited number of suitable ports could exacerbate these issues.
Challenge
Towage operations have safety and logistical challenges. Towing platforms at slow speeds in ports and harbour areas can be disruptive, creation of collision risks with other traffic, disruption of fishing activities and the need for seeking shelter on long distance tows are all new impacts.
Solution
For demonstrator projects, this has been managed on a case-by-case basis, with bespoke passage plans and risk assessments. However, for commercial scale projects, a more systematic approach to managing towage might be required, such as defined towage corridors and practices.
Challenge 4. Maintaining UK energy security
Tankers frequently loiter off the British coast sometimes awaiting berth availability and for other commercial and operational reasons.
Such practices are regular in the port approaches to Milford Haven and vessels greater than 300m in length, including LNG carriers, regularly slow steam around the Celtic Sea.
Challenge
The sensitivity of UK energy security and the safety of hazardous cargoes could be compromised by the presence of FLOW sites.
There is an increased collision risk potential through the reduction of available sea space, increased risk of grounding by offsetting these vessels towards the coast and potential contact/allision risks with floating platforms.
Solution
Planning of FLOW sites should take account of the need to maintain existing practices in a safe and effective manner.
Developers should engage with ports and harbours need an early stage to ensure UK energy security it not impacted.
Challenge 5. Spatial squeeze of fishing and recreational activities
The Celtic Sea contains a diverse range of mobile and static fishing gear activities across the region as well as recreational routes crossing between the Cornish, Welsh and Irish coasts. These activities could be displaced from the array areas, increasing interaction and risks with other traffic, so called spatial squeeze (NFFO, 2022).
Challenge
During construction there will be periods where unmarked subsurface infrastructure, including subsea cables and mooring equipment, could pose a risk to other vessels and snagging from fishing gear and ship anchors.
If, as is predicted, there’s routine towage of FLOW platforms between the array area and a port or wet storage areas there could be impact on fisheries with loss of gear or need for relocation.
Solution
Engagement with fishing and recreational users throughout the development process to minimise disruption including the location of wet storage areas.
Collection of good supporting evidence base, such as vessel traffic surveys, to identify where these activities occur.
Challenge 6. Cumulative impacts
The significant pipeline of FLOW projects is likely to result in greater prominence of cumulative effects. Potential exists for 4GW in a limited sea space and as of October 2022, developers had declared 3.7GW of planned development (RenewableUK Energy Pulse October 2022).
Challenge
Project-specific, piecemeal assessments may no longer be fit for purpose.
Interactions between adjacent projects, such as forming narrow corridors, could pose safety risks whilst concentration of activities in the relatively few suitable ports greatly increases impact on navigation.
Alongside safety, there are potential issues with planning and assessment methodologies being able to assess multiple and fast evolving projects in a co-ordinated manner.
Several projects all happening concurrently in the same region puts a significant burden on consultees’ time and resources, increasing frustration amongst stakeholders with the planning process.
Solution
Alongside project specific Navigation Risk Assessments (NRA), cumulative regional NRA’s are likely to also be required.
Finding mechanisms to engender a more co-ordinated and collaborative approach would be beneficial. Creating a regional stakeholder engagement forum, like the Maritime Navigation Engagement Forum set up for The Crown Estate Round 4 OWF projects Morgan, Mona and Morecambe in the Eastern Irish Sea, could help address concerns of stakeholders and reduce stakeholder fatigue.
Summary
Floating offshore wind developments bring different potential shipping and navigation risk and impacts when compared to fixed foundation projects.
None of the challenges associated with FLOW are insurmountable, although it is crucial to get ahead of these impacts and come up with solutions before the first commercial project.
NASH Maritime's risk management specialists not only know the region and stakeholders but also how each of these challenges can be managed so that the ambitions for the Celtic Sea region and floating wind can be realised.
To discuss the issues outlined in this blog post get in touch with Jamie Holmes Offshore Energy Lead.
