Kim Jonny Karlsen was at home last month when a 20-tonne turbine blade the length of a Boeing 747 broke off its tower at the nearby Odal wind farm and crashed into the fir trees below.
“I jumped up from the sofa and called a friend who works there,” said the former mechanic. “I wanted to check if anyone was hurt.”
No one was harmed. But the 163-megawatt development in remote eastern Norway, whose turbines are made by German group Siemens Gamesa, has remained offline since the incident, its second major technical fault this year.
Component failures have occurred at wind farms all over the world as the sector grapples with quality challenges following rapid growth of both the global fleet and turbine sizes amid a drive to cut use of fossil fuels to meet net zero emissions targets.
While many of the problems affect the inner workings of the turbines, the Odal accident is not unique, with blade losses reported this year at another wind farm in Norway as well as sites in the US and Scotland.
The industry does not publish precise failure rates, making it hard to ascertain how widespread defects are. However, high provisions for payouts on warranties — guarantees a manufacturer offers to repair or replace faulty products — have helped push turbine makers to steep losses in recent years.
Big wind turbine manufacturers’ warranty provisions accounted for an average 5.4 per cent of revenues in 2023, according to analysis by Wood Mackenzie. That compares to 2.8 per cent in 2018, although it is slightly down on a high of 5.7 per cent in 2022. The figure covers Chinese companies Goldwind and Mingyang and European companies Vestas and Nordex.
It does not include Siemens Gamesa, whose parent company Siemens Energy set aside nearly €2bn last year in provisions for warranties and onerous contracts mostly connected to problems with two of Gamesa’s onshore turbine platforms. The figure amounts to 22 per cent of Siemens Gamesa’s annual revenue or 6.3 per cent of Siemens Energy’s revenues.
“There is no option here; they need to sort it out,” said Endri Lico, supply chain expert at Wood Mackenzie, who warned that warranty provisions risked dragging on manufacturers’ recovery. “It’s not sustainable.”
Some manufacturers are trying to slow down the rapid introduction of new models, and focus on quality and standardisation. Yet insurance experts say supply chain strains are adding to the disruption of individual failures. Meanwhile, rising competition from Chinese manufacturers risks putting pressure on turbine makers to rush out new models again.
It comes as the surge in interest rates over the past few years has created difficulties in the capital-intensive wind sector, particularly among developers of offshore projects in the US and the UK, several of which were stalled or abandoned last year.
The wind industry added a record 117-gigawatt of new capacity last year despite the challenges, according to industry group the Global Wind Energy Council, taking the total installed globally to more than 1 terawatt from less than 200GW in 2010. Almost 500,000 turbines are now in place worldwide.
The expansion has been matched by sharp increases in size, with average turbine capacity rising from 2.5MW to 4.8MW for onshore models and from 5MW to 9.6MW offshore, according to GWEC figures.
Yet the growth has come at a cost, with industry executives and analysts saying rapid development and undeveloped supply chains have created strains.
“There’s no time to optimise the new turbines,” said Feng Zhao, head of strategy and market intelligence at GWEC. “The launch of larger models to win the market has generated concern about reliability.”
“We seem to have had a bit of an immature way of constantly launching new products in this industry,” said Morten Dyrholm, senior vice-president at Vestas. “There has really been an extreme race.”
Turbines coming on to the market are not “as mature” as previously, according to Espen Hagstrom, head of wind technology and quality at Norwegian renewables developer Statkraft, Europe’s biggest renewable energy producer, noting they were now commonly installed while still going through certification. “Things should have been identified earlier than what we have seen.”
Vestas, one of the world’s largest manufacturers, booked warranty provisions in 2022 of €930mn, or 6.4 per cent of its revenue, while US company General Electric’s renewable energy business also cited high provisions as its slumped to an annual loss of $2.2bn the same year.
In an attempt to boost quality, the latter — now GE Vernova — said last year it would streamline new products, while Vestas and…
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