The local head of global wind O&M company ONYX InSight sheds light on the forces that can degrade performance of these massive and complex assets.

With about 2,700 turbines working around the country to generate nearly 9GW of electricity, the wind industry is a major contributor in Australia’s efforts to transition away from its reliance on coal. Wind technology is enormous and expensive, however, and owners rely on stringent operations and maintenance regimes to ensure predictable revenue.

With a team in Australia monitoring almost 300 machines and about 15% market share of software monitoring across the sector, ONYX InSight regional manager Australia and New Zealand Hiren Limbachiya talks to EcoGeneration about the importance of keeping a close eye on what’s happening inside those big propellers.

Hiren Limbachiya says there is more to O&M than preventive maintenance.

What are some common things that can go wrong with wind turbines?

There are three key issues. Firstly, there are blade-related problems, which tend to be the most challenging. Common issues could be blade bearing cracking, damage on the blades due to lightning, erosion and corrosion of key bolts and structures. Secondly, damage to generator bearings, planetary gearboxes and planetary bearings, which are costly to rectify. Finally, main bearing failure is another significant problem related to rotating components.

Other common issues could be structural or electrical, affecting the whole turbine outside of the blades and drivetrain.

What does turbine operations and maintenance involve in practice?

Wind turbine O&M is usually broken down into a few broad categories. Preventive maintenance concerns scheduled work where expenditure is budgeted for, in an effort to identify problems early to mitigate their severity. Corrective maintenance – also known as repair or capital replacement – is typically unplanned and/or condition-based. It must be timely and effective to avoid penalties. Finally, there is monitoring, which includes condition-based monitoring, diagnostics, alarms and other information-gathering activity.

Beyond that, O&M can incorporate billing, accounting, subcontractor management, enforcement of warranties, insurance, site maintenance and leasing.

How does ONYX InSight’s technology work?

Our condition-monitoring hardware, ecoCMS, is a smart condition monitoring solution for wind turbines and industrial machinery which uses mobile computing technology combined with micro electro-mechanical systems (MEMS) sensors.

Our cloud-based software platform, fleetMONITOR, is used to analyse ecoCMS data and provides dashboard views for alarms and trends, through to detailed vibration analysis tools for the analyst.

Condition monitoring using ONYX InSight’s technology provides extremely long lead times before component failure, offering significant savings in downtime and repair cost.

How can monitoring cut opex costs?

Micro electro-mechanical systems have radically enhanced the return on investment for turbine condition monitoring, helping wind farm owners make significant opex savings. By cutting the cost of condition-monitoring systems (CMS), low-cost MEMS sensors have helped wind farm owners to refine their repair and maintenance strategies, improve operational planning, cut unscheduled maintenance and make opex savings of up to 8% a year. MEMS sensors are used in CMS hardware to measure and report on vibration, temperature and oil condition in the drive train. Using the right technology for condition monitoring means longer lead times for component failures can be predicted, which can result in significant savings.

What’s the difference in monitoring onshore and offshore wind?

Fundamentally there’s no difference in monitoring onshore and offshore wind. However, offshore wind turbine monitoring is critical as inspection is not always possible due to the logistical costs involved.

The cost of downtime for offshore assets is a lot higher compared to onshore turbines, due to vessel hire and limited maintenance windows throughout the year. Offshore wind turbines are usually larger in size, increasing the cost of parts, so setting up appropriate alarm rules is incredibly important. FleetMONITOR is used for monitoring offshore wind farms in Europe, the US and Asia.

Is it hard to monitor across different manufacturers?

It can be hard as they are fitted with different systems. Some don’t have factory fitted CMS systems. However, fleetMONITOR was developed to allow migration of data captured by other CMS. For example, across Australia and New Zealand we have migrated data onto fleetMONITOR from manufacturers such as Vestas, Siemens and GE, enabling integrated predictive maintenance.

What are some differences between maintenance of key turbine brands?

The key differences occur depending on whether turbines are direct drive or gearbox driven. With gearbox-driven turbines, there are more rotating parts, cooling systems, oil and the gearbox itself, which means more parts to maintain. With direct-drive turbines, the generator is larger and the main bearing is relatively larger, increasing the difficulty of repairs. There are also very large power electronics to consider for direct drive wind turbines.

Any comments on the Australian wind sector more widely?

Australia’s fast growing wind energy sector is the largest renewable source of energy in the country. By March 2020, wind energy was at a total installed capacity of 6,279MW, with more than 2,700 operational wind turbines in Australia. There are 30 projects under construction or committed, expecting to add another 5,635MW. Eight wind farms were commissioned between 1999-2005 with a total of 271 turbines and in the coming decades we will see the proportion of ageing assets rise as the sector matures.