Do Offshore Wind Farms Need a New Maintenance Model?

Operations and Maintenance (O&M) – it’s a crucial aspect of any renewables project and represents a sizeable proportion of the overall cost of a typical installation. What’s more, the topic of maintaining renewables assets, especially in the offshore environment, is something that is only going to grow in importance. With more and more new schemes coming on stream, and a continued global push – driven in part by governments such as that in Germany – for electricity generation schemes to be located in our seas, the techniques used to complete maintenance effectively and minimise downtime will doubtless be developed and refined in the coming years.

But what if the very model used by many operators today to decide maintenance requirements in the first place is flawed? What if a lack of guidance or knowledge is leading operators to turn a blind eye to necessary routine maintenance, and rather rely on expensive reactive maintenance? And what if not enough is being done to assure the integrity of an offshore installation in its entirety as a complete asset, and with it sustained and reliable electricity generation into the future? The current means of maintaining offshore wind farms — which in the case of every project is an extremely valuable set of equipment combining as one asset — is at best in need of radical improvement, and at worst threatening the safe and reliable operation of renewable projects, particularly those located offshore.

So how are things done at the moment? Let’s look at a typical offshore wind farm installation. For a wind turbine, maintenance will be driven principally by the recommendations made within the original equipment manufacturer’s (OEM’s) manual. Some will need to be carried out in order to ensure the equipment is covered by the OEM’s warranty, while some may be necessary to achieve certification. It’s a similar case when you look below the water line and consider the maintenance of the turbine foundations, although warranty periods tend to be much lower making the drive to complete proactive maintenance lower. When it comes to legislative or certification guidance in relation to inspecting sub-sea components meanwhile, the answer is not yet clear or united and therefore, to date, demands placed on operators are minimal. Beyond requirements laid down in the consenting process which may compel the installation operator to complete certain maintenance requirements in a scheme’s early years, plus some draft guidance, there appears to be very little advice or support for a thorough process of maintenance definition.

Such an approach might at first appear attractive to renewables operators. After all, by meeting purely the limited demands of OEMs and consenters, costs for operating and maintaining plants are low, initially at least. But crucially this is a maintenance regime that lacks any long-term inspection of the critical subsea elements of an installation which could and perhaps should be seen as the highest risk areas of a project — whether that risk is financial, commercial or health and safety related. It also, critically, does not reflect the fact that the entire offshore installation should be seen as one entity – the success of an offshore wind farm and its ability to generate cost-effective electricity long into the future does not rely on the individual wind turbines, but on the complete wind farm as a system.

The upshot of taking such a simplistic approach to O&M is it means that it is impossible for an operator to truly understand all the risks that its installations might be subject to. It therefore brings with it enormous risks — to the plant’s integrity, to the safety of personnel and to the operator’s costs and ultimately reputation if things go wrong. Furthermore, by adopting a reactive attitude the through-life costs of the plant cannot be quantified, meaning that the plant’s overall commercial value might reduce should refinancing be necessary or when insurance is being placed. However, these are all significant risks that can ultimately be effectively minimised if the very concept of maintenance is rethought.

Welcoming the awkward neighbor?

There needs to be a sea change within the industry when it comes to maintenance. Renewables operators should be seeking a better, fuller understanding of the risks of their plants and a greater understanding and confidence in the costs associated with managing these risks. This can be easily done without a defined code or guidance and should be the minimum requirement for any project.

Things must start with operators elevating the priority of maintenance of installations, and at the same time taking a more proactive attitude to managing assets throughout their lifecycle. The tendency to be satisfied with repairing assets only when something goes wrong needs to stop.

If we look at the maintenance regimes that are currently commonplace we can start to identify what would be an optimum solution for operators. Classic Asset Management is one method, where assets are managed so that the greatest return is achieved. However, this overly focuses on asset value from a real time commercial view point, rather than considering factors such as value or risk throughout the project’s life.

Classification and Certification of a scheme to meet legal or design standards requirements is another option and will, in time, be how the industry moves forward. However, presently there are few comprehensive requirements yet in existence for renewables operators. These are currently being drafted, although potentially without consideration for the wind farms that are in our waters already. Yet a lack of guidance should not get in the way.

Renewable operations should be seeking a better, fuller understanding of the risks their plants face (Source: OMM)

An approach based on Verification, where quality control and an assessment of risk are jointly considered, points to a way forward. It can also ensure the critical elements of an installation — an underwater cable for instance — remain in good repair and condition. To begin to define maintenance needs from such a risk assessment perspective is, it may be argued, what renewables operators should be considering as standard practice. It is an area that has been the subject of increasing focus of late in order to develop the tools operators need to define requirements independently and cost effectively.

The renewables industry, which in the grand scheme of electricity generation is of course still in its infancy, has done much to pioneer new generation techniques and establish itself as an important and independent part of the energy mix. At the same time, there is much to be learned from other industries. When it comes to maintenance, the oil and gas industry offers a perspective on how things could be done differently – with a verification mechanism properly integrated.

Of course, despite both being involved in the business of generating power there are enormous differences between the two industries and many of the technical challenges faced vary significantly. Yet there are a number of important similarities that underpin the assertion that a new maintenance model — one based on the principles developed by the oil and gas industry — is precisely right for offshore renewables operators. For example, plant integrity and cost are of paramount importance regardless of what industry the operator is in. Further, the physical location of installations — by its nature the marine environment is often hostile and rather difficult to access — is similar in many cases.


Inspection, Repair and Maintenance (often abbreviated to simply “IRM”) is widely accepted as the de facto maintenance model used by oil and gas operators. It is an approach that has been developed and refined for many decades and one that helps ensure the integrity of platforms and the safety of its personnel. At the same time, it is one that reflects the comparatively high degree of regulation within the oil and gas industry — the fact that platforms are manned structures means that the health and safety of personnel drives the need for inspection and maintenance routines. This is something that, up until now at least, is generally of less a concern to offshore renewables.

However, while the oil and gas attitude may appear overbearing and overly risk-based, what it does result in are maintenance plans that are systematic and thorough, while also adaptable and flexible enough to be easily updated through the lifecycle of the asset — something that is not typical in the renewables industry at present.

The result of adopting an IRM approach is that it is common in the oil and gas world for repair work to be driven by the inspection of assets, rather than the other way around. The plans for maintenance of assets are then a product of these inspections. In short, it provides a sensible means of maintaining a plant that can be translated well to an offshore renewables environment — although for the wind industry’s purposes such a methodology may perhaps be renamed Inspection, Maintenance and Repair (or just “IMR”) to reflect the fundamental importance of maintenance in the first place.

IMR in practice

So how could an Inspection, Maintenance and Repair (IMR, rather than IRM) verification-based inspection and maintenance model be developed and what should renewables operators be doing?

The first stage is to identify all of the inputs to the maintenance plan — all the data sources that exist that could inform how and when maintenance needs to be completed. This would include, but not necessarily be limited to, a thorough review of existing OEM maintenance manuals for each asset, along with data from the pre-build stage (such as that included in original consent and construction documentation, or what might already have been commissioned by the operator separately). At a higher level, it is also important to follow the operator’s own quality standards if appropriate, as well as gain an understanding of what industry-wide certification and best practice exists from sources including national governments and trade bodies.

Next is to return to the installation itself and ascertain which elements of it could be considered safety critical — which parts of the entire system, be they physical components, power circuits or software, could lead to (or in some smaller way contribute to) a major incident occurring if they were to fail? This allows the scope for an inspection and maintenance plan to be produced.

Risk assessment tools can then be used to map the safety critical elements of the installation with the data source inputs that were identified at the first stage, developing an assessment tool that is tailored to offshore wind farms and carefully takes account of the environment within which the Safety Critical Elements of a scheme exist, be that higher than average seabed mobility or specific tidal patterns, for example.

With a full understanding of the safety critical risks, a set of performance standards can then be drawn up which precisely determine the performance that is required of each of the safety critical elements of an installation — essentially assessing each element in relation to its survivability, reliability and availability. These standards therefore act as the basis for managing each element on an ongoing basis.

The performance standards then give way to the ultimate output that operators will be looking for — a Written Scheme of Examination, the maintenance plan itself. This is where the criteria and tactical arrangements are produced for verifying that each safety critical element meets the performance standards already identified.

The crucial final step of implementing IMR is something that has been directly borrowed from the oil and gas industry — independent verification. With an inspection and maintenance plan carefully produced, an organisation such as the Inspection Verification Bureau may be used to confirm its suitability and, in the absence of any current obligatory certification, certify the plan for use on the renewables scheme. This final check, which can be completed via a mixture of physical examinations, technical reviews or desktop audits, is what qualifies the plan and also means a full cost assessment of maintaining each critical aspect of an installation is produced. This is something that can also be repeated as often as the Written Scheme of Examination demands; to ensure that maintenance requirements are adequately updated throughout the installation’s lifecycle.

A clearer future?

IMR represents a flexible approach to maintenance that has the potential to offer significant benefits to operators. It gives these organisations, and in turn their funders and insurers, confidence in a scheme’s integrity. And it helps ensure that only the most appropriate and necessary maintenance is taking place, while at the same time placing operators in a better position to avoid the need for costly and time-consuming repairs if things do go wrong. Surely, for any renewables scheme, there can be nothing more critical than that?

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