When it comes to running offshore wind farms, operations are tightly constrained by wave heights, weather windows, installation and maintenance methods, and fleet vessel limits. The constant interplay between these factors dictates when assets can be built, accessed, or sometimes even operational.
Last year, NeuWave completed its first full pilot in the Celtic Sea while partnered with the Vekta Group. And we’ve finally got our hands on the results!
By applying NeuWave’s high-precision data models, Vekta were able to more accurately predict seasonal weather windows and significantly reduce weather-related downtime.
Want to find out how we achieved this?
Let’s dive in!
NeuWave Celtic Sea pilot methodology
The NeuWave–Vekta pilot programme was launched in Feb, 2025, and covered the entire operational season. NeuWave hindcast wave height (Hs) data, spanning 13 years, was used to plan and execute the installation (laying and burial) of 50 array cables by the Vekta Group in the Celtic Sea.
This data was compared directly against ERA5 model outputs (the current industry standard, and Vekta Group chosen tool), to determine weather window availability across the project timespan and site range and predict wave-driven downtime.
Throughout our industry research, we’ve found that ERA5 data is too coarse for many site requirements, operating at a 30km resolution (compared to NeuWave’s 500m operability).
Before we dive into the pilot programme results, let’s take a look at the region and environmental reality that affected the specific project requirements.
Understanding the Celtic Sea context
From an operations perspective, the Celtic Sea is one of the most environmentally demanding in the country. Compared to more sheltered basins, the Celtic Sea is characterised by longer-period Atlantic swell, complex seabed conditions, and rapidly shifting weather systems that regularly undermine long-term planning that is reliant on legacy models.
These factors combine to make offshore construction and O&M planning significantly more sensitive to accurate metocean data (particularly wave conditions).
So what does that mean for cable laying projects in the Celtic Sea?
Wave height and wave period directly influence vessel motion, deck workability, and the safe operation of burial and trenching equipment. In marginal sea states, small differences in modelled wave conditions can determine whether a task proceeds or a vessel stands by.
Key environmental and operational characteristics of the Celtic Sea include:
- Exposure to Atlantic swell, producing persistent wave energy even during low local wind conditions
- Highly variable sea states with short weather windows that can open and close quickly
- Greater distance from shore, increasing transit times and amplifying the cost of missed weather windows
- Operational reliance on smaller support vessels which often have stricter Hs limits than primary installation vessels
Traditional regional reanalysis datasets such as ERA5 provide useful large-scale trends, but their spatial resolution can smooth out the localised wave behaviour that ultimately governs day-to-day offshore operability.
For cable installation activities specifically, wave conditions frequently represent a stronger operational constraint than wind. Whilst wind limits are often well understood and consistently applied, many cable lay and burial tasks are constrained by wave-induced vessel motion.
Application of precision data for Celtic Sea subcable lays – the results
Across the pilot programme, NeuWave data was able to indicate marked improvements in predicted site accessibility. The Vekta Group reported weather-driven downtime to be reduced by approximately 50% when compared with ERA5 results.
That’s a considerable optimisation, and could save larger offshore wind farm projects millions of pounds or weeks of operations. This improvement reflects the ability of high-resolution modelling to capture local wave behaviour that is smoothed or misrepresented in coarse regional datasets.
The trial was a resounding success, and offered solid proof of concept – NeuWave’s hindcast precision wave data enables more accurate costing and planning for operations and installation projects. And the tool has proven that it can accommodate the changeable complexity of the Celtic Sea, analysing dozens of cable runs while accounting for multiple vessels and installation methods simultaneously. NeuWave data cut installation timelines by 22% (or approximately 1 month in the project cycle).
Value Point 1: Shorter workable weather windows
The improved resolution of NeuWave’s wave data allowed the Vekta team to identify short, workable weather windows that were not visible in ERA5-based planning. In a region like the Celtic Sea where sea states can shift quickly, these marginal gains accumulate across a full campaign, translating into more productive vessel days and fewer extended standby periods.
Value Point 2: Method-specific operability assessments
The modelling enabled method-specific operability assessments. Different stages of cable installation (lay, burial, and post-lay intervention) have distinct wave sensitivity thresholds. By applying high-resolution Hs data to each activity type, the project team could more accurately sequence operations and allocate vessels according to realistic environmental constraints, rather than broad seasonal assumptions.
Value Point 3: More confident commercial forecasting
The data supported more confident commercial forecasting. Weather downtime is one of the largest uncertainties in offshore installation budgets. By narrowing the gap between predicted and likely on-site conditions, the NeuWave–Vekta workflow reduced contingency inflation and improved transparency in schedule risk discussions with project stakeholders.
In short, in high-energy, weather-sensitive regions like the Celtic Sea, better environmental intelligence directly translates into safer planning and stronger schedules. These results don’t reflect the relaxation of safety thresholds or operational limits; the reduction in predicted downtime arises from improved alignment between modelled and observed site conditions.
With the Vekta Group reporting NeuWave data to perform “significantly better” than legacy methods, the partnership are looking to further prove the concept during live construction works, rather than solely at the planning stage.
This case study shows how precision wave data translates directly into day-to-day operational value. More accurate weather windows, better vessel utilisation, and clearer schedule expectations all reduce friction offshore.
In challenging regions like the Celtic Sea, small improvements in environmental understanding can unlock significant gains across an installation campaign. The result is not only greater efficiency, but more predictable, lower-risk offshore operations.
Precision data that pays for itself…
NeuWave delivers high-resolution wave intelligence designed for offshore construction and O&M, enabling teams to understand site-specific conditions, refine weather window analysis, and reduce unnecessary conservatism in marine operations.
