According to Renewable UK, there are currently 40 operational offshore wind projects in UK waters. This means that more than 2,250 turbines are being continually battered by the waves and wind in often remote and hostile environments. Such structures clearly require regular monitoring and maintenance to ensure optimum operational integrity and longevity if they are to play their part in carbon neutrality goals over the next three decades.
In 2009, the average nameplate capacity of a now “teenage” European offshore wind turbine, such as Vattenfall’s Horns Rev 1 boasting 80 turbines, was about 3 MW. This is expected to increase to 15 MW over the next decade. While larger turbines will generate more electricity, ensuring the commercial viability and efficiency of smaller, first and second-generation turbines is critical to keep up with the growing demand for electricity while installation of their bigger siblings is underway.
Innovative technology to understand the health status of last generation turbines, and to know when to administer preventative or protective measures, is the cornerstone of reducing operational costs, thought to be in the region of 60-80%, of O&M activity.
Treating turbine troubles
There are two key cost components for the O&M of wind turbines that need to be minimised: those for scheduled maintenance and unscheduled maintenance. If component failures lead to unscheduled stoppages, then the additional cost of lost electricity sales is incurred. Considerable efforts are clearly being made to control and forecast such failures.
Using advanced digital tools, data collation and evaluation can influence and balance the need for both scheduled and unscheduled maintenance costs using trusted information from many parameters and variables such as the sea state or weather conditions. However, while the amount of data is plentiful, analysing and validating its relevance to widen operational windows, reduce risk to the maintenance crew, and support improved cost-efficiency and ultimately decision-making, is challenging.
Miros, a provider of proven high-performance Internet-of-Things (IoT) sensors measuring real-time sea state data, uses bathymetrical studies during the planning and development phase of wind farms, as well as existing operational offshore wind farms to retrofit the technology, to identify the most suitable sensor locations. Placing RangeFinder sensors for example, at specified turbine and offshore substation (OSS) locations across the wind farm site not only allows for a more accurate weather forecast but will also provide a more precise holistic overview of the varying sea state conditions, unique to every individual wind farm. This enables operators to make safer, more informed decisions especially in relation to O&M activities.
Strategically placed sensors will support safer and more efficient O&M planning, execution and life extension activities. As well as providing significant cost and operations benefits to new offshore wind farms, the Miros IoT solution can also retrofit smart technology into existing first or second-generation infrastructure where the access and sharing of data can be difficult.
Offshore wind opex modelling undertaken by the University of Strathclyde has shown on a typical modern offshore wind site (~ 500 MW to 1 GW scale) with multiple Miros sensors could provide an opex saving of between GBP 300,000 and 1 million and a reduction of 5% CO2 emissions per annum. 
Smart, safe and secure sensor solution
In 2019, Miros began working with Vattenfall on Horns Rev 1, one of the Swedish developers’ first-generation projects, offshore Denmark.
The Horns Rev 1 operations team had experienced difficulties with its wave buoy and was becoming disillusioned with the traditional wave and weather forecasting provided by metocean vendors. Data accessibility and the means to share real-time, accurate data with many stakeholders, including vendors and employees, within a safe and secure system, was also an issue and was hampering critical decision-making on necessary O&M, as well as planned life extension activity.
As a solution, Miros installed five wave radars plus one weather sensor across the project site as part of plans to extend operations to the end of this decade. Vattenfall was also keen to allow third-party access to real-time sea state data to support relevant suppliers and stakeholders to analyse and improve daily operations.
Data is only one click away
The entire project team has quickly realised the operational benefits and cost savings of using the self-calibrating sensor technology. By adopting the Miros Cloud platform, the Vattenfall team is seeing a positive impact on the reduction of employee time and resources across several internal stakeholders (Site Operations, SCADA, IT, Metocean, Asset Integrity, etc.).
For example, a project manager based remotely and the operations manager at the marine operations base can simultaneously view the actual sea state conditions on-site on real-time dashboards, accessible anytime on any device. This directly impacts the decision as to when it is safe for personnel to be transported via crew transfer vessel (CTV) for conducting maintenance activities.
With the help of IoT-enabled Miros RangeFinder sensors, distributed across the wind farm, the team can easily see the variation in sea state across the entire site at any time. In certain scenarios, it is possible to perform maintenance in one part of the wind farm where the sea is calmer while weather conditions in another area may be more unfavourable to work in. Previously due to sole reliance on weather forecasts, there would be a high probability of waiting on weather. However, now having quick and easy access to real-time data also contributes to avoiding wasted or aborted vessel trips and therefore also contributes to the overall reduction of CO2 emissions.
The benefits of improved communication of the sea state and weather parameters are also extended to the project’s external stakeholders (i.e., Weather forecast providers, vessels, engineering consultancies, research programs, universities, etc.) which could be up to 50 or more simultaneously. Meaning that whether they are working part or full time on the wind farm, being able to always have direct access to exactly the same data as their client, supports more collaborative, solid, and true working conditions. Public, live data from Horns Rev 1 can be seen at Miros.app.
Enhancing knowledge and extending operations
The Vattenfall project has proven that the combination of appropriately chosen locations to source data from and full IoT capability is vital to facilitate:
- Easy access and sharing of data to all internal and external project stakeholders simultaneously.
- Real-time decision support.
- Post-operation analyses.
- Future planning.
- Long-term asset integrity calculations.
For wind farm operators, this dynamic approach gives more influence and control on operations, while for service providers, it gives credibility and assurance that contract expectations can be delivered on schedule and importantly, on budget. This “plug and play” technology will also contribute to lowering carbon footprint, an essential step forward for the energy industry in its drive to lower emissions. From an operational perspective, rather than decommissioning wind farms and turbines, they can be refreshed and renewed.
Green energy remains the biggest opportunity to tackle climate change. Securing significant improvement in this vital area is viewed as the most important lever for the energy transition.
With more than a decade spent working within the supply chain in the ever-evolving energy sector, Miros’ Maggie McMillan has been riding the renewable wave since 2014. As a staunch advocate – and catalyst – for the continued rise of offshore wind, Maggie embodies Miros’ commitment to enhancing the safety, sustainability and performance of offshore operations.