The wind sector continues to grow steadily along with an increasing demand for clean energy. By the end of 2017, more than 500 GW are expected to be in operation worldwide. The industry’s expansion started with the development of smaller farms in Europe and was followed by larger farms in North America, China, and emerging markets. New farms are being constructed offshore, first in Europe and most recently off the US coast. It’s an exciting time for wind power.
TIP #1 EMBRACE ASSET PERFORMANCE MANAGEMENT
Asset Performance Management (APM) can be described in many ways, but one compelling and useful definition is simple: Don’t try and fix something that is not broken. Why perform unnecessary maintenance, incur costs and introduce risk? APM seeks to apply the most optimized maintenance to achieve overall LCOE goals.
Most wind farms operate under a “preventative” or “time-based” maintenance approach as recommended by original equipment manufacturers (OEMs), while some operators choose the higher risk “run to failure” approach. None of this is acceptable if O&M optimization is the goal. Going forward, owner-operators need a non-invasive way to determine if action is needed.
OEMs suggest regular maintenance at specific intervals. For example, the tower should be climbed once a year for a change of oil, to tighten bolts, to change brushes, and so forth. But time-based maintenance is not the best way to maintain wind turbines. Wind speed, velocity, turbulence, and other weather conditions may be vastly different on one side of the array than on the other. Terrain elevation and geography also cause wind turbines to operate in very different and unpredictable ways. Every wind farm is unique. There is really no way to supply a common approach to maintenance with something that is so variable.
TIP #2—CONSTANTLY MONITOR YOUR WIND FARM
Advanced condition monitoring techniques and the experience gained by those techniques are critical to reliably manage wind farm assets. For example, planetary/helical gearbox failure is a primary concern for manufacturers and operators. As much as 25% to 30% of wind farm operating and maintenance costs are associated with the gearbox alone. Converting to a digitized wind farm enables operators to keep a constant eye on gearboxes and all other components.
When a defect is not significant, the dependable knowledge gathered via continuous monitoring can enable reduced, but constant operation and revenue generation while the repair is conducted. Most importantly, it mitigates the risk of secondary damage, run-to-failure, an unplanned outage, or a catastrophic event.
Beyond gearboxes, other major components can incur heavy usage as well as extreme loads that are susceptible to both wear and fatigue. These include generators, main bearings, the tower itself and its base, and blades. Employing asset performance condition monitoring across the fleet helps operators plan efficiently for and coordinate maintenance outages.
TIP #3—DETECT ISSUES EARLY
Being able to predict, assess, plan, and optimize turbine conditions helps drive more efficient operations and maintenance working practices lowers costs and reduces risks. Because turbine aging diminishes reliability and increases the risk of failure, it is important to consider contributing factors:
• Load and usage that has been extracted from the asset
• Variability of the usage, and how hard it’s been driven over time
• Quality of the original turbine design, manufacturing, and construction
TIP #4—CONTROL YOUR RISKS AND WARRANTIES
Reliability engineers understand the “bathtub” graph. It defines the key phases of a turbine’s life cycle, allowing operators to adapt to changes during the life of an asset. Notably, the graph illustrates the transition from OEM warranty-covered risk to risk that must be covered by the owner-operator going forward.
This shift in responsibility increases the importance of understanding new risks that must be addressed to maintain the asset throughout its anticipated life cycle. Risks that must be mitigated, include unplanned maintenance for component failures, issues related to fulfilling power-supply contracts, trouble meeting safety targets, and issues relating to achieving business/shareholder objectives. Managing risk is essential to achieving availability and reliability targets.
Risk factors are constantly changing; a component that used to come with a five-year warranty now might offer only two-year warranty coverage. Risk can become harder to predict and potentially more time consuming and onerous to mitigate. Despite vendor testing and modeling, wind farm operators cannot truly know what issues lie ahead during a turbine’s life cycle in a variety of locales and hostile environments.
A digitized wind farm can determine and document areas of risk well ahead of warranty expiration, thus mitigating the owner operator’s exposure. In addition, end-of-warranty assessments, informed by digital analysis, can transfer additional negotiating power to the owner when determining warranty responsibility.
TIP #5—GAIN INSIGHT ABOUT REMOTE LOCATIONS
Wind turbines are unlike many other fixed-power generation assets. Most often they operate in remote and difficult-to-access locations, which makes it challenging, extremely costly, and labor-intensive to manually observe and qualify turbine conditions. In addition, wind turbines operate at variable speeds, under continual adjustment, and are influenced by such factors as wind patterns, turbulence, wind speed, direction, and velocity.
The Industrial Internet of Things (IIoT) today is more than a buzz word about some imagined future. It is key to an increasingly digitized world, and can immensely impact wind farm efficiencies and cost savings. Among its greatest advantages is giving owner-operators the ability to monitor wind farms located in remote locations, perhaps days away from a central office.
The challenge is particularly acute in the case of offshore wind farms. It’s not uncommon in Europe to see wind farms 30 miles off the coast, and the trend should accelerate as floating bases and foundations eventually allow for wind farms in deeper waters. As for the US, as of mid-2017, there are 28 projects totaling 23,735 MW of potential installed capacity in the works off US coastlines.
It’s clear that the need to monitor wind farms remotely—often very remotely—will be the order of the day. Whether located on land or on water, a digitized wind farm gives a control center the ability to monitor a great deal of a turbine’s operation regardless of the distances involved, and on a real-time basis. This allows the owner-operator to develop best-of-breed maintenance strategies, and give greater priority to underperforming turbines.