Maximizing offshore wind lifespan with operations and maintenance

Thanks to major advances in both the technological methods used and the richness of the datasets available on the condition of wind farms, it is becoming easier for developers and operators to look beyond daily operations and take steps to ensure the long-term structural health of their assets. This supports the scaling up of overall energy production from offshore wind, which – alongside planning and constructing new capacity – will require the uptime and lifespan of the existing infrastructure to be maximized and extended.

The offshore wind industry continues to make steady progress to become a larger part of the global energy mix. While it is still an industry finding its feet and maturing in terms of its processes and structures, capacity is scaling up. The latest data from the Global Wind Energy Council (GWEC) found 2024 to be a record year for offshore wind construction, with 8GW of grid-connected capacity added worldwide. It also forecasts a compound average growth rate of 21% for the industry, equating to 350GW of capacity to be added over the next decade.

As offshore wind portfolios expand, developers and operators – along with the broader supply chain – face mounting pressure to reduce the levelized cost of energy (LCOE) and deliver financially viable alternatives to fossil fuels. Achieving this is critical for meeting government-set net-zero targets and will require meaningful support through government-backed incentives. As the ratio between total discounted lifetime cost and total discounted lifetime production, LCOE is the ‘holy grail’ in the offshore industry. It is relied upon by wind farm operators to demonstrate that they can provide the most cost-efficient solution in a highly competitive arena.

A changing O&M mindset

In offshore wind, operations and maintenance (O&M) has historically been seen as a reactive function, with remedial work carried out only after damage to infrastructure. The market focus was primarily on reducing upfront capital expenditure, with operational expenditure (OPEX) receiving less attention. But in the face of new expectations placed on the industry, and with a more detailed understanding of the causes and impacts of offshore wind failures, mindsets are changing. The downtime and delays of the past are no longer acceptable, and O&M is now increasingly seen as offering real preventative value by identifying potential issues before they escalate. Asset monitoring, as part of a wider, more robust O&M strategy, is a prime example. This enables operators to maximize uptime and extend the overall lifespan of wind farms, while positively contributing to project OPEX.

Offshore conditions are notoriously unforgiving, and even more so in the case of floating wind farms located further out at sea. Wind farm operators must not only contend with continually shifting environments, but also ageing structures. They therefore need assurances that the benefits of wind farm developments will not be overshadowed by high O&M costs during an asset’s lifetime. To that end, a robust inspection and monitoring programme to identify and correct issues such as fatigue, corrosion and marine scour is vital to help ensure remediation work takes place before the asset’s integrity and – eventually – uptime is adversely impacted.

Inspection and monitoring technology

Technology plays a pivotal role in monitoring the condition of wind farms to keep them operational. Thanks to major advances in both the methods used and the richness of the datasets available on the condition of wind farms, it has been possible to reduce the frequency of subsea inspections. Automated data delivery, alongside visualization capabilities, now provides real-time access to data and supports continuous remote monitoring of assets.

To further enhance O&M insights, operators should also consider the long-term benefit of creating a digital twin of their offshore asset. This would integrate all the available geospatial data gathered from site investigations, asset inspections and monitoring.

More informed decision-making

With a rich dataset of this kind in place, decisions can be made much more quickly, and condition-based and preventative maintenance can be decided on a per-turbine basis. Rather than selecting turbines at random to meet an acceptable inspection quota, operators can connect insights from geodata and inspection data to optimize the inspection regime.

In an area of high seabed movement, for example, operators may decide to increase the inspection frequency to every two years. Conversely, for turbines in areas where seabed movement is minimal, they may reduce it to every four years. By utilizing the data from structural monitoring sensors embedded within infrastructure, targeted inspections can take place, checking for damage and deformation, or tracking marine growth and corrosion. If unusual vibration levels are detected, for example, the asset can be prioritized in the inspection programme.

The benefits of USVs

Alongside continuous asset monitoring, advances in marine vessel design, connectivity and remote operations have led to options like uncrewed surface vessels (USVs) emerging. These reduce the risk exposure for human crews, as well as transforming how inspection work is carried out, because they make continuous, 24/7 operations possible for extended periods.

USVs also allow for data collection from particularly hard-to-reach areas, whilst also providing contractors the option to carry out multiple scopes of work in one deployment, helping manage costs. Furthermore, by reducing fuel consumption and eliminating the need for large support vessels, USVs support significant reductions in carbon emissions.

Goal: 25 years of operation

Alongside planning and constructing new capacity, scaling up overall energy production from offshore wind will require the uptime and lifespan of the existing infrastructure to be maximized and extended. The goal should be for wind turbines to stay operational beyond 25 years.

The most progress towards this will come from the asset owners that continually push the boundaries. Forward-thinking developers will be those able to look beyond daily operations and take steps to ensure the long-term structural health of their assets. These organizations will see O&M as the source of competitive advantage and a way to maximize capacity factors, control LCOE, and extend asset life. They will gear their O&M strategies more towards risk-based inspection rather than scrambling to respond to emergencies. And extending the lifetime and value of their assets can really pay off for society too. With each additional year existing offshore wind farm capacity stays in operation in the UK alone, approximately 20GWh in renewable energy is generated – the equivalent of powering 14 million homes.

Further reading

Data from the Global Wind Energy Council (GWEC): https://www.gwec.net/news/offshore-wind-installed-capacity-reaches-83-gw-as-new-report-finds-2024-a-record-year-for-construction-and-auctions

Challenges when designing and locating wind farms

The design and location of wind farms can significantly influence the types of vulnerabilities that can emerge. Some examples include:

Marine scour: Water movement strips away sediment, leading to structural fatigue over time. Monopile foundations in shallow, high-current zones are particularly susceptible to scour.

Subsea cabling: Geographic factors such as continuous seabed mobility – the gradual shifting of sediment caused by wave and current action – can result in cable burial, exposure or displacement, potentially pushing systems beyond their operational limits. A cable may have been adequately buried at installation, but sections can become exposed months or years later, leaving them vulnerable to environmental degradation and external interference. Activities such as fishing and anchoring can inadvertently damage exposed cables. Frequent inspection and monitoring, along with close coordination with other seabed users, is essential to ensure adequate protection of affected sections.

Proximity-related challenges: When wind farms are built close to one another or near infrastructure from other sectors such as oil & gas or telecommunications, a range of O&M-related risks can emerge, including interference, vessel congestion and cable strikes. For example, the ‘wake effect’ reduces the wind speed behind turbines, directly impacting the energy output of nearby installations. Disputes over asset positioning are already becoming more common globally, and proximity-related challenges are expected to intensify in the coming years as the industry continues to grow. This underscores the importance of accurate measurement and modelling to support effective planning and mitigation.