September 21 (Renewables Now) - To scale up renewable energy capacity and ensure a successful global energy transition, developers will need to install high-capacity farms in deeper offshore sites. Houlder’s Chief Operating Officer, Mark Goalen, shares his specialist insight on the key considerations around the floating foundation type that must be evaluated to achieve this.
Solid (floating) foundations…
Selecting the most suitable floating foundation type for a given location is a key technical barrier to floating wind commercialisation. Every development is unique; water depth, seabed type, environmental conditions are just some of the factors that must be accounted for. There are many floating foundations to choose from, but they can essentially be categorised into four main structure types: spar buoy, tension leg platform, semi-submersible platform, and barge.
They all have fundamental differences in their characteristics that affect how the turbine responds to environmental conditions, so a primary factor that should heavily influence foundation selection is its motionn response to environmental conditions. Understanding the effect of motion characteristics on the whole system is essential. It directly impacts all components from nacelle, tower, to the dynamic cable, and the mooring system.
No single, definitive structure type or floating foundation will be optimal for every site. There are many variables that will impact the decision, including a technologies’ operability, reliability, practicality, readiness, CAPEX, OPEX and potential longevity to name a few. A developer must choose a foundation that is most suitable for the wind farm they are developing, and that will vary from site to site.
Effectively selecting a floating foundation involves collaborating with the right partners to analyse a combination of technical and operational factors. Importantly, it should be recognised that operational factors may have a bigger impact than technical ones over the asset’s lifecycle.
Supply chain challenges
One vital operational factor that will determine floating foundation choice is the project’s supply chain. Indeed, constructing the required infrastructure and putting in place the appropriate supply chain is one of the largest barriers to quick and effective floating offshore wind commercialisation.
Turbines, foundations, mooring system components, cables, and port infrastructure, are all critical elements of the supply chain that must be considered. Transport routes, logistics, infrastructure as well as installation and O&M (operations and maintenance) needs make matters complex. To attain a clear understanding of all supply chain requirements and optimise their floating wind projects, it is key that developers and other stakeholders have a holistic understanding of the development and how it varies from fixed wind which many are more accustomed to.
In addition to this, until the foundation type is known, the supply chain cannot form, and investment cannot be made in port infrastructure. Infrastructure, location, water depth, available space for fabrication, and storage are all important for ports that will support new floating wind development.
Operating and maintaining assets
Taking a deeper look at O&M, cost and resource-efficient O&M is a key element that developers must consider from the outset of a project. If not properly considered, O&M can become a major barrier to the commerciality and day-to-day running of a floating wind farm.
Floating foundations are currently towed back to port for maintenance and repairs. However, this will not remain feasible or economical as wind turbines are located further offshore and the distance to O&M ports increases. The ability to conduct O&M on-location must be developed, because the risk and costs associated with connection, disconnection, and transportation of the wind turbines will prove too high over time. A combination of modifying the turbine, as well as developing the tools and offshore support vessels required to support this O&M phase, will be crucial to the success of floating wind projects.
Taking full advantage of available solutions
To summarise, floating offshore wind is a truly exciting global opportunity that will play a key role in the energy transition. However, there are barriers to full commercialisation that must be addressed and overcome. Choosing the right structure type and floating foundation for each site is a key step in the right direction but this is not an easy decision to make. Technical challenges, such as a floating foundation’s motion response to environmental conditions, must be considered. Plus, there are several operational factors to analyse, including supply chains, port infrastructure, and O&M.
The bottom line is that to effectively commercialise floating wind, developers can benefit from independent consultancy. Involving marine and offshore design and engineering specialists from the start of a project can ensure that costs and risks are minimised, timeframes are realistic, and efficiency is maximised. With the right collaboration, and investment supported by technical analysis, the barriers to floating wind can and will be overcome. Ultimately, this will allow floating offshore wind to fulfil its potential in supporting the global energy transition.