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United States

Lean times require smooth running

US: These are sober days in the US wind market. The industry is patting itself on the back for bringing 9.5GW of wind online last year despite the downturn. But the deployment is based largely on momentum carried over from when developers were ordering hundreds of megawatts at a time. The building will continue, but what is most pressing now for wind plant owners facing leaner times is keeping the existing fleet running smoothly with high quality operations and maintenance (O&M) regimes.

Times are changing in O&M too. Two or three years ago, service contracts from the original equipment manufacturer (OEM) attached to a turbine sale were short, often between two and four years. Now, because those same OEMs are pulling in less cash from turbine sales, they are stepping up their sales pitches for O&M because profit margins on service are good and they need to offset lower turbine sales.

"Three years ago, when we bought turbines, a lot of suppliers said: 'We'll provide the parts but that's all we'll do.' Now there are ten-year service contracts on the table," said Scott McBride, regional operations manager for Padoma Wind Power, at a recent conference on O&M.
It is true that no one knows the machine better than the engineers who designed it and, in a good relationship, the interests of OEM and owner would be aligned during the warranty and service stages. But it is not always so, which is one reason why conducting an exhaustive end-of-warranty inspection is essential.

This year, as Merritt Brown of Rev1 Wind explains (page 12), is the long-foreseen tipping point where more operational wind turbines will be coming off OEM warranties than are currently covered. Component failures will be the plant owner's responsibility. Thorough inspection before this shift in responsibility - with the OEM watching on - can minimise the surprises and service charges down the road.

It's no surprise now that few turbines will reach their 20-year service life cycles without major repairs. The trick for operators is to anticipate problems and minimise and manage the costs. And this is where condition monitoring systems (CMS) help. There are various systems available, pre-installed or retro-fitted, which monitor components and warn of incipient failure. Operators can then schedule repairs, source parts and often consolidate a few repairs with one costly crane hire.

But there, too, there is nuance. US wind plant operators are debating how much to invest in the systems, and appear to be looking for new turbines to be pre-installed with CMS, with some of the cost being absorbed by the O&Ms. In this buyers' market, that just may come to pass.
The value, however, of adding a monitoring system as an after-market upgrade is not shared by all operators (page 6). While CMS on new machines is standard in Europe, required by most insurance policies, only around 10% of operating wind turbines in the US employ it, with vibration monitoring being the most common. Iberdrola, for example, is using CMS on 100 of its 2,500 North American turbines to measure its value and cost-effectiveness.

With data flooding in, the difficulty now is how to interpret it and see the overall picture. A CMS system may detect increased vibration throughout the drive train, but is it a gearbox concern or did a wind gust tax the rotor plane? Robert Poore of DNV Global Energy Concepts says: "We need to use multiple sources. You don't know what you'll need or want in the future." By aligning CMS information with data from the turbine's supervisory control and data acquisition (Scada) system, questions can be answered more clearly, eliminating error and maximising repair expenses, such as sharing crane hire across a number of repairs. By combining gearbox oil analysis results with those of a borescope camera run through the gearbox, precise problems can be established.

Good maintenance saves money

The US turbine fleet has historically been performing around 10% less than pre-construction estimates. Financial investors in wind projects have been among the first to notice because, if 10% fewer dollars are flowing in, their investment will be tied up in a wind plant for longer. Many factors can contribute to underperforming wind plants, but a good O&M constantly evaluates and investigates if a turbine performs against expectations.

A significant amount of downtime is often just the time it takes for technicians to get to a project, says Marty Crotty, president of AES Wind Generation. Often, he adds, operators are too satisfied to simply react and resolve problems and don't spend enough time doing forensic analysis into the root cause of downtime or sub-optimal performance.

The charge for O&M providers is a noble and difficult one. If identifying, understanding, and resolving underperforming wind projects was easy, "we would have already figured it out by now", says Poore.

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