New wave: wet storage, floating offshore wind and consenting new technology

What is wet storage?

As part of our series on Celtic Sea offshore wind, this article explores the concept of wet storage, as well as wider conversations about handling new challenges that arise from brand-new technologies from an environmental impact/consenting perspective.

So what is wet storage? While fixed turbines can be assembled at their final location, installing floating turbines – usually at greater water depth than fixed foundations – is more challenging from an engineering perspective. Instead, floating turbines may need to be assembled and temporarily stored in wet storage areas prior to being towed out to their intended position. This could happen in the water at portside or at another location close to shore.

The concept of wet storage for offshore wind could become more prevalent in floating projects than it has been for fixed foundation offshore wind.

The "shock of the new"

Any discussion of floating offshore wind will tell you that from an engineering perspective, this technology is still at a relatively early stage of development. No commercial-scale floating wind projects have yet been constructed, although there are several currently in the consenting process as part of the ScotWind and INTOG leasing rounds. Wet storage technology is still being developed, so both capability and associated consenting guidelines will be subject to change.

This hasn’t held back UK leasing rounds solely or largely devoted to floating wind projects, with around two thirds of ScotWind projects proposed as floating wind. ScotWind and Celtic Sea Round 5 floating projects can also expect to share similar environmental  and consenting challenges; the two regions should aim to benefit from each other’s learnings as projects progress. 

Related news: supporting the 3.6 GW Ossian floating wind project and the 1 GW Ayre floating wind project.

Wet storage and environmental impacts

A range of potential social/human and ecology impacts will need to be assessed during consenting for wet storage projects. Broadly speaking, these might encompass visual, cultural/heritage, birds (likely focussed on displacement), underwater noise as a result of installation techniques, marine mammal (for example, potential impacts on seal haul-outs or disturbance in the marine environment), and seabed habitats to name a few. There is also potential for impacts on existing offshore industries such as commercial fisheries and shipping and navigation that will require assessment.

The importance of stakeholder engagement

Understanding potential impacts and how the project infrastructure might affect human and ecological receptors is key for floating offshore wind projects. That is why, when it comes to new technologies like floating offshore wind and wet storage in particular, stakeholder engagement will be critical. Here are some ideas to consider: 

• Some of the potential impacts might be unfamiliar to both statutory and non-statutory stakeholders, as well as to developers and their consultants.
  
  
• Stakeholders may need to find a balance between ‘living with’ data gaps associated with a new technology and putting plans in place for monitoring and mitigation of potential impacts post-consent. 
  
  
• At Tetra Tech RPS Energy, we believe that, as part of the stakeholder engagement process, the industry needs to understand current levels of ‘uncertainty’ associated with potential activities and resulting impacts – this is more likely to enable quality conversations on the issues raised during stakeholder engagement. 
  
  
• Working collaboratively with statutory and non-statutory stakeholders, academics and consultants will help developers find solutions to some of the new issues associated with consenting of wet storage projects, and thereby support the growth of the floating offshore wind industry. 

Related read: Engaging with commercial fisheries and other sea users during Celtic Sea offshore wind projects