That is especially so in the US where wind farm owners typically have larger fleets with a homogeneous installed base of workhorse turbines such as the GE 1.5, Siemens 2.3, Vestas V82 and Gamesa G90.
The trend was highlighted by the recent signing of a major contract between the Vestas-owned UpWind Solutions, and Berkshire Hathaway Energy and its MidAmerican Energy and PacifiCorp subsidiaries. Vestas will maintain 1.75GW of GE 1.5s and 1.5sle turbines across 15 sites in Iowa, Wyoming and Oregon.
This raises sensitive issues about rivals servicing each others turbines. "There's certainly a competitive intelligence piece to this (trend)," said Make Consult's Aaron Barr, adding that there is "some execution risk" to such a multi-brand service strategy.
Shermco Industries' Kevin Alewine, co-chair of the O&M working group at the American Wind Energy Association (AWEA), pointed to the inevitable issue of rival OEMs having to police their intellectual property. "That's a battle," he said.
For example, in Vestas' new contract: "Will GE tell Vestas the programming and converter keys?" he wondered, if a generator needs to be changed. "(Vestas) is going to have to have a very believable firewall" around UpWind. But he agreed it is in each company's interests to comply. "If GE doesn't play nice, (MidAmerican) could say, I'll buy Vestas next time."
Vestas' vice president of services, Peter Wells, stressed the "firewall" around UpWind. "We are very careful with information flow," he said, pointing out that even before the UpWind deal, Vestas serviced about 1GW of GE turbines in the US and Canada.
Asked if Vestas has encountered problems through servicing competitors' turbines, Wells said: "Most OEMs will gravitate towards being more commercially minded," and will comply with Vestas' servicing because it is prudent to do so commercially.
Wells is former CEO of UpWind, which Vestas bought in December. At the time, UpWind was the US's largest independent service provider (ISP) for a broad range of brands. Vestas also bought German ISP Availon in January, which services turbines including Gamesa and Enercon.
The two purchases continued Vestas' strategy of being a global leader in servicing and moving into a multi-brand model. By the end of the year, Vestas estimates that a quarter of its servicing will be multi-brand, Wells said. This includes new deals being negotiated. GE recently finalised at least one contract to service non-GE turbines, a spokesman confirmed, though details were confidential.
Should OEMs be concerned about the intelligence that rivals can gain from servicing their turbines? Art Eunson, GE Renewable Energy's general manager of onshore wind services, said: "Obviously the more you work with a machine, the more you learn about it." But he stressed that GE focuses on wind farm output as a whole, not just the turbines.
Of the possibility of added risk for GE in Vestas' contract to service the Berkshire Hathaway projects, he only said: "It's not rare for companies, including GE, to service other manufacturers' machines, either directly or indirectly through a subsidiary company."
Gamesa also services other turbines. In May it bought a 50% share in NEM Solutions, a Spanish developer of applications to manage predictive maintenance, currently used in 20.6GW of installed capacity.
In fact, all OEMs are expected to move into multi-brand servicing if they can, said analysts. One interesting question is, in multi-brand servicing will the OEM service provider or the project owner carry the risk on capital spares? That is, who would pay to replace a rival's major components? Vestas says that with a full-service contract, it will carry the risk, including on non-Vestas turbines.
According to Make, the $2-billion North American service market will grow to $2.75 billion in annual spending by 2021. That includes in-house servicing, which more of the US's typically large owners are moving towards in order to leverage economies of scale. The global market will grow from $9.7 billion in 2015 to $19.3 billion in 2024.
More mergers and acquisitions are expected in the US service sector. OEMs are seeking income that is more stable than turbine sales, and asset owners are expanding their own in-house capabilities and increasingly offering third party servicing. Few true ISPs remain in the US, except for speciality service companies such as Shermco and Gearbox Express.
E.on launched a US service industry in April 2015, which contracts with other owners. NextEra has long operated and maintained others wind projects, although it keeps a low profile in doing so. And Duke's renewable energy service company, which some time ago absorbed Outland Energy Services, also does third-party work.