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The irresistible allure of gargantuan Chinese wind turbines

Supersized rotors promise to be a game-changer for North Sea project economics, but are the touted benefits too good to be true?

Chinese wind turbine manufacturers are pushing the boat out when it comes to blade lengths, and positioning themselves to make an alluring value proposition to North Sea project developers. But they face an uphill task to earn their technical stripes and overcome geopolitical headwinds to break into European markets.

Goldwind and MingYang are deploying in their home market 16MW-rated platforms with blades spanning up to 130 metres long. MingYang is going even further, developing an 18MW-plus platform with 140-metre blades. The larger swept areas of these machines offer significantly higher yields and lower cost of energy compared to the latest models being rolled out by incumbent Western turbine suppliers to the North Sea market.

Analysis by efwd reveals that Chinese turbines, if proven reliable and financeable in UK waters, could make a material difference to the economic viability of North Sea wind projects being built over the coming years.

For projects that have already secured a Contract for Difference (CfD), opting for the largest possible swept area could generate hundreds of millions of pounds of additional revenue for the same strike price over the 15-year lifetime of the CfD. For those hoping to compete in future CfD rounds, the larger swept area would allow projects to bid well below others, potentially giving Chinese machines the edge over Western rivals.

Cautious growth

Western OEMs have taken a cautious approach to turbine scaling by restricting the rate of blade length increases relative to turbine power output. Turbines rated in the double-digit-MW capacities have, for the large part, retained rotor diameters at or below 200 metres.

For example, Vestas stuck with a maximum rotor diameter of 164 metres when moving from its 8MW to 10MW platform. Siemens increased rated power by 38% when it moved from an 8MW to 11MW platform but increased maximum rotor diameter by less than 20% (167 metres compared to 200 metres).

The latest iterations of offshore platforms are seeking to address this shortfall by expanding rotor diameters beyond 200 metres. Vestas’ 15MW machine features rotors up to 236 metres, GE’s 14MW Haliade-X uses rotors up to 220 metres and Siemens’ 14MW platform rotors span 236 metres. These blades lengths represent a step-change in technical ambition, and yet they already pale in comparison to the latest Chinese turbine platforms.

The cautious approach to blade length increases is attributable to two main factors. Firstly, the Western OEMs are treading carefully to deliver higher rated powers without running the risk of compromising structural integrity. 

Second, development of turbine power trains occurs semi-independently from innovation in blade designs. This is what allows OEMs to offer several blade length options for each MW-class turbine: Vestas’ 4.2MW turbine has rotors ranging from 117 to 150 metres. But even when looking only at the top end of rotor diameters available in the market, a non-linear trend in rated power and blade length correlation is clear.

Throwing caution to the wind

The truly humungous Chinese turbines are threatening to eat Western OEMs’ lunch. Goldwind’s GHW252-16MW platform has 252-metre rotors and blades measuring 123 metres, implying a radius of 130 metres. CSSC Haizhuang is bringing forwards an 18MW model with 260-metre rotors, while MingYang has a 16MW platform with 260-metre rotors and this year unveiled plans for an 18MW-plus machine with rotors spanning a whopping 280 metres – currently the biggest turbine known to be under commercial development anywhere in the world.

Rotor scaling has an oversized impact on turbine power yield, and the latest Chinese turbines are in a class of their own on this metric. For example, GE’s 220-metre rotor would theoretically generate roughly 4.4MW at a constant wind speed of 8.5 metres per second (m/s). Vestas and Siemens models with 236-metre rotors would generate about 5MW in the same conditions.

The step up to the 252- and 260-metre rotor being trialled by Goldwind, MingYang and CSSC Haizhuang boosts output to 5.8MW and 6.2MW, respectively, at the same at 8.5m/s wind speed. And MingYang’s gargantuan 18MW platform with a 280-metre rotor would theoretically yield 7.1MW – an increase of 61% on the GE model.

If these outputs prove to be achievable and reliable over the 15-year lifetime of a CfD – a big ‘if’ – the revenue achievable from each turbine leaps by the same proportion, as illustrated below.

Economies of scale

This uplift revolutionises project economics. By using publicly available wind data from the NAREC met mast offshore Blyth in Northumberland, efwd calculated the theoretical output from turbines with varying rotor diameters at a real offshore wind site in the North Sea.

Take for example the Hornsea 3 project, which won a CfD in the fourth CfD allocation round (AR4) at a strike price of £37.50 per MWh in 2012 money (equivalent to £50.42/MWh adjusting for inflation). This site can accommodate up to 231 turbines for a maximum nameplate generating capacity of 2.85GW.

Assuming Hornsea 3 wind speeds are comparable to the Blyth met mast, and the project were to use GE’s 14MW platform, it would require 203 turbines to make maximum use of the seabed acreage without breaching the rated capacity limit. Those units would generate in total 42GWh per year across the full range of wind speeds, cutting in at 3m/s and topping out at 25m/s.

A Hornsea-sized array of 231 GE units would generate 8.5TWh per year. At the inflation-adjusted AR4 strike price of £50.42/MWh, this output implies gross revenue of £427 million per year, or £6.4 billion over 15 years.

But if Hornsea were to deploy MingYang’s 16MW model, it would require only 178 units to achieve a similar rated capacity, which would reduce fixed costs. Moreover, each turbine would produce 55GWh/year and the entire project would generate 9.8TWh – an increase of 15% over the GE configuration.

Revenue would increase by the same proportion to £492 million per year, or £7.4 billion over 15 years. That’s a difference of £967 million in total gross revenue over the lifetime of the CfD.

Sharpening the bid

Chinese turbines are most likely to be deployed at future North Sea projects that are yet to secure a CfD. efwd analysis shows how larger rotors improve a project’s auction competitiveness.

Let’s imagine a hypothetical future 4GW offshore wind megaproject in pre-development and aiming to compete for a CfD in the year 2029. If that project was designed around Vestas’ 15MW platform, it would require 266 turbines to hit nameplate capacity. If designed around MingYang’s 18MW prototype, which might be commercially available in time for the CfD auction, it would require 44 fewer turbines for the same capacity.

And even with an additional 44 Vestas machines, the project would generate 1.4TWh less electricity than if using the MingYang model. If the auction cleared at the same AR4 strike price of £50.42/MWh (adjusted for inflation), this reduced output translates into £1.1 billion less revenue (-11%) over 15 years using Vestas machines compared to using MingYang.

However, the AR4 clearing price might not be competitive in 2029. Using the larger MingYang turbines would allow the project to lower its bid by 10% to £45.27/MWh and still generate the same amount of revenue as a similar project using the smaller Vestas turbines, but with lower costs from using fewer turbines to do so.

This analysis illustrates why the race for scale in the so-called turbine ‘arms race’ is proving so irresistible to developers. Compared to the next generation of flagship offshore wind turbines being developed by Western OEMs, Chinese giants definitely have the edge – on paper, at least.

Still much to prove

The caveat is that the calculations above are purely theoretical until Goldwind, MingYang and CSSC Haizhuang can break into the European market in a big way. Key to doing so is proving their operational reliability at this monumental scale to the satisfaction of Western investors, lenders and insurance underwriters.

This is easier said than done. MingYang installed a 7.25MW turbine on a floating platform earlier this year to power a CNOOC oil and gas field in the South China Sea, but there is a dearth of available operational data from deployments inside China. The inability of Western developers to audit wind turbine performance poses a barrier to placing firm orders.

For this reason, Chinese turbine OEMs are seeking to secure small orders for single units or small batches at floating wind demonstrator projects in European waters.

Industry sources tell efwd that MingYang is bidding aggressively to supply turbines to Hexicon’s 32MW TwinHub floating wind project in the Celtic Sea, which won a CfD in AR4 at a strike price of £87.30/MWh (in 2012 prices). Installing a pair of 16MW turbines atop one of Hexicon’s TwinWind floating foundations in UK waters would give MingYang’s utility-developer customers confidence in the reliability of its technology.

Supply chain weaponisation

MingYang established a business and engineering centre in Hamburg, Germany, in 2020 from which to launch its expansion into European markets. But there is an open question over how much of the turbine supply chain will be relocated to the markets that the company intends to serve.

While many of the components used by Western OEMs are already sourced in China, there is an expectation – or perhaps a belief – that turbine companies listed on exchanges in London, Frankfurt and New York would audit their supply chains within China.

GE, Vestas and Siemens are already under immense pressure from shareholders to improve financial performance. They can ill afford to be marked down on ESG factors such as heavy embedded emissions from carbon-intensive manufacturing processes or human rights abuses.

The offshore wind industry will also be wary of exposing itself to geopolitical trade risks. Accusations of slave labour in Xinjiang were cited by US politicians to justify the imposition of trade quotas and import barriers against solar panels produced from certain Chinese polysilicon factories in 2021.

Supply chain weaponisation recently took on a new twist, with China imposing export curbs on critical minerals essential to the production of semiconductors and solar panels. This was a tit-for-tat response to measures introduced by the US, the Netherlands and Japan to restrict the sale of high-end chipmaking equipment abroad.

Unstoppable momentum

Chinese turbine suppliers are pushing the envelope on rotor size and using compelling economic arguments to break into the North Sea and other European wind markets. Developers are under immense price pressure to secure a route to market, so will find the value proposition of 18MW-plus turbines hard to resist – particularly as they move into floating wind, which will by definition be more expensive than fixed foundation projects.

“When Western OEMs start talking about halting or pausing the turbine arms race, it is the easiest play in the world for Chinese companies to come in and say, ‘OK, I’ll build you a 20MW machine’,” a senior executive at a global energy infrastructure company told efwd.

Judging by recent bidding behaviour, there is a widespread assumption that bigger turbines are coming. The winning bids at California’s first federal offshore wind lease sale in the Pacific indicate that all developers designed their floating wind sites on the assumption that 20MW machines will be available by 2030, “which is scary”, the infrastructure source said. “You’re talking about nacelles that weigh three of four hundred tonnes. The cranes to lift those don’t exist today.”

The relentless policy focus on cost of energy, combined with the parlous state of Western OEM corporate finances, is providing a golden opportunity for new entrants to shake up the turbine supply market. Competition and innovation cannot be stopped, so as long as the cheapest projects are given priority access to market there will always be an incentive to push the boat out a little further in the quest for scale. Whether the next wave of mammoth machines can overcome reliability and supply chain challenges remains to be seen, but there is a strong incentive to try.

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