Vestas also said that warranty provisions were down to a record low 1.6% of total revenue in 2012, compared with 3.1% in 2011 and as high as 4.4% in 2008. This positive turnaround in Vestas' upkeep could explain why 77% of all in-house wind turbine service contracts were renewed in 2012. A key performance indicator is minimising the lost production factor. This is a variable defined as the electricity production — and thus revenue — that could have been generated had the turbine been operating when the wind was blowing.
However, it is no secret that during the past decade Vestas has faced a prolonged and difficult period, with several difficult-to-resolve technical issues affecting its main volume models. "Victims" included the popular older-generation V66-1.65MW and V66-1.75MW sister model series, the V80-2MW successor model introduced in 2000, and the lightweight V90-3MW turbine. The latter groundbreaking design for onshore and offshore application was introduced in 2003 with high hopes that it would become the leading wind technology not only for Vestas but for the entire wind industry. The V90-3MW is characterised by a compact drivetrain, incorporating an innovative flanged gearbox with an integrated single rotor bearing solution and new-generation slender, lightweight rotor blades.
Despite two different technology platforms, multiple project developers and technical consultants familiar with the products and specific operating periods have reported common failures, especially with gearboxes and generators. Additional pinpointed typical failure areas include hydraulic pitch-control systems and software-related issues, problems reinforced by inadequate service organisation capacity and performance. Vestas senior technical officials talked about several of these issues during my previous visit to the company's Aarhus R&D centre in 2009. They also highlighted that the occurrence of multiple product quality and service/upkeep-related issues coincided with an unprecedented high growth period for the company.
Recalling past issues, Vestas chief technical officer Anders Vedel explained that in 2005 the company made a concentrated effort to improve quality. "This focus is perhaps best described as a continuous product and process improvement programme, which took off in 2006 and incorporated a number of distinct measures," he said.
"One key measure was the introduction of Six Sigma [a set of tools and strategies aimed at process improvement and optimisation] for both Vestas' internal organisation and our suppliers. We further invested heavily in the improving of staff capabilities, introducing new equipment and advanced testing facilities. The latter are by definition required for new products aimed at building of high-level in-house capabilities for scientifically sound validation of main results."
Vedel added that service performance is largely dependent upon the availability of well-trained technicians, specialised service teams and a technical support organisation capable of an immediate response. Vedel said: "Another key area is maintaining adequate spare parts supply at geographically well-positioned centres, with a main focus on minimal response time and speedy delivery to minimise turbine and wind farm downtime."
Defending Vestas' product portfolio without going into specifics, Vedel said: "The V90-3.0MW remains a good offering for demanding IEC class I high wind speed sites and others with height constraints. Our V112-3.0MW is showing its worth after a tough ramp-up period in late 2011, and the V164-8.0 project is on schedule for prototype installation next year."