The challenge and opportunity of scaling up floating offshore wind

The hype about offshore floating wind continues to grow, and its potential has already become part of the pre-election buzz in the UK. But how realistic are the ambitions for the sector? Writing for Utility Week, Jonathan Morton and Jody Anderson from Haynes and Boone explore the significant hurdles to be overcome in scaling up the industry safely and successfully.

For the world to realise the promise offered by offshore wind, the use of floating technology is essential. Fixed offshore wind systems can only be installed in water depths up to 60 metres, which rules out around 80% of potential European ocean real-estate. This inability to tap into wind resources at deep or complex seabed locations can be solved by floating structures, a fact which is particularly significant for states that lack a shallow coastline but are keen to invest.

From an energy harvesting perspective, winds blow stronger and more consistently further out to sea. These amplified conditions allow floating wind installations to increase their capacity factors, with floating wind farms potentially achieving significantly higher rates than fixed offshore turbines (for example, BW Ideol’s Flotgen pilot achieved a 61.96% capacity factor in December 2023, while the average for fixed bottom was around 45-50%).

The industry consensus is that floating wind has been proven conceptually and now needs to be scaled up. Currently, a few small-scale projects are operating successfully, with notable commercial windfarms at Hywind Scotland and Hywind Tampen in Norway.

With the next UK general election rapidly approaching, the Labour party has announced its intention to invest in building floating wind farms off the British coast, via a state-owned corporate operating with an £8.3 billion budget, in an effort to reduce reliance on foreign energy, and the current Conservative government have allocated £160 million of grant money to a floating offshore wind manufacturing investment scheme (FLOWMIS), focused on the much-needed development of UK port infrastructure.

The government is also currently consulting with the industry regarding its proposed CfD Sustainable Industry Reward (SIR) allocation framework, which would incentivise activities such as investing in Tier 1 manufacturing and/or ports in UK deprived areas, including parts of Wales and North East Scotland, and considering the social and economic benefits to proposed projects. This is all to be welcomed.

However, the gulf between prototypes and serial manufacture is enormous. The technological, logistical, and legal hurdles, specifically the lack of standardisation in the emerging technologies relating to foundation design; supply chain constraints; current port infrastructure; and uncertainty regarding operations and maintenance, are potentially overwhelming. With growing interest in new markets and new regions, these obstacles form a significant industrial challenge and need to be addressed head-on.

Lack of standardisation

There are four main types of floating structure: spars; semi-submersibles; tension-leg platforms; and pontoons/barges. Each type has multiple varieties of proposed design from a wide variety of potential suppliers. While each has its own merits and shortcomings, no single structure type will be optimal for every site and every project, and the industry is keen not to stifle innovation by restricting the pool too early.

However, should such a variety in design remain, the sector will be unable to benefit from economies of scale in its operations, as facilities will need to be adaptable with regards, for example, to wet storage and laydown areas. Portside water depth may also a problem, depending on the design used (for example, a spar requires water depth of around 90 meters, while a semi-sub would need only around 15). This can be avoided if the industry settles on a more limited range of designs or design principles, and certification from recognised bodies such as DNV and Bureau Veritas is put in place to enable standardisation to occur.

Supply chains

The industry is currently in the early part of the transitional phase moving from experiment to large-scale. The UK is a long way from having the manufacturing resources necessary to produce the structures quickly enough to meet future demand. This is not just about sourcing the necessary quantities of steel or concrete or manufacturing the large numbers of dynamic cables or other components, but also the lack of a sufficiently trained workforce. There is also a significant global shortage of vessels for transportation and installation, and the long lead time required to build them means work needs to start now.

The market needs the promise of long-term projects to risk investment to get the necessary capacity, and this requires commitment from governments and a collaborative attitude in the industry. Constraints to supply chains have been cited as the reason why so far only demonstrator projects have been successful, with Shell and Equinor both blaming supply chain restrictions for project abandonment and delays, respectively, and it is good to see this has acted as something of a wake-up call.

Port infrastructure

At present, British port infrastructure does not meet the specifications needed for full-scale production and implementation of floating offshore wind. The competitiveness of subsidy allocations and general market uncertainty means that vital upgrading to existing ports has not been forthcoming. Problems with planning delays remain an issue, and it is helpful that the Crown Estate is intending to offer discounts to developers where such delays occur.

With the Labour party’s plan to invest via a state-owned company, it can be assumed that some of the budget allocated will be for the upgrading of current port sites. However, this public funding alone may not be enough to make the improvements required, and private investment should be encouraged.

Operations and maintenance

The uncertainties regarding costs of operation and maintenance are a further potential barrier to full-scale commercialisation. Floating structures will be constantly in motion and the risk profile is hard to predict. Contracts will need to be carefully worded to ensure a fair allocation of liability and major component replacement or serial failures are particular areas of concern. While towing the structure to shore for repair seems workable, it is not ideal particularly where sites are further out and the danger of damage occurring during the journey is significant. Avoiding the need for such major repair is obviously ideal, and the use of innovative technology such as drones, AI or UAVs may help, and potentially lower costs and minimise personnel risk. With all this in mind, the industry will be watching closely when Hywind Scotland has its first major maintenance after five years of operation in the summer of 2024.

In summary, harnessing wind in previously unreachable seabed locations has the power to greatly assist with the global energy transition and the UK has the capability to be at the forefront of the industry. Although there is a great deal of excitement and evidence of growing state-support for full-scale commercialisation, it will not be achievable without the many hurdles being overcome. This will require leadership and courage from government and investors, and work needs to start now if the UK does not want to find itself left behind.