One notable exception was the release of fresh details on Enercon’s 7.0MW E-175 EP5 E2 flagship model, which “uåX˜äŠÊ˜·³Ç unveiled last month.
Offshore, while Vestas and Siemens Gamesa are both ramping up their 14-15MW flagship models with identical (maximum) 236-metre rotor diameters, the latter has so far remained tight-lipped about its ‘minimum’ 20MW next-generation giant and 2024 prototype.
Exhibition revelations
A Bilbao exhibitor told me that he had been tipped off to go and see the blades for Siemens Gamesa’s latest prototype while they awaited shipment to Denmark’s Østerild prototype test site.
He quoted a blade length of 135 metres, producing a rotor diameter of up to 276 metres based on a 6-metre hub diameter – common for such turbine sizes.
The source further quoted a nacelle mass (back end plus generator) of 1,000 tonnes, exactly double the 500 tonnes of Siemens Gamesa’s 14MW SG 14-222, which suggests he actually meant head mass instead.
The head mass (nacelle plus rotor) of Mingyang’s 18MW MySE 18-292 medium-speed prototype, with a 292-metre rotor, is by comparison less than 800 tonnes, according to official company product documentation.
Assuming that the rotor diameter is indeed 276 metres, it is possible to deduce a realistic matching power rating by evaluating past Siemens Gamesa product launches and the company’s power trend development over time.
Three significant model announcements in the past few years include the SG 8.0-167 DD, with a specific power rating of 365W/m2, the SG 11-200 DD with 350W/m2, and the SG 14-236 DD with 320W/m2 in nominal mode and 343W/m2 with a maximum 15MW ‘power boost’.
Choosing 350W/m2 – and taking into account that a larger rotor benefits from better energy-rich wind energy that is swept in and distributed down the rotor from higher atmospheric layers – the calculated outcome is 21MW.
Both rating and rotor size were independently rumoured long before and confirmed at WindEurope by another wind industry source who claimed that “it is widely shared public wind industry knowledge by now”.
Naturally, I spoke to Siemens Gamesa to ask the company if it was prepared to verify the claims, but it remained tight-lipped.
Possible nameplate
The scaling step from 14MW/236m2 to 21MW/276m2 itself represents a 50% rating increase and 37% in rotor swept area. These variables together offer an estimated increment in annual energy production (AEP) of 30-35% or more for the upcoming offshore giant, under comparable high-wind IEC I conditions.
Our working assumption is that the new turbine’s possible nameplate will be nominal SG 21-276 DD, and without eventual Power Boost functionality engaged.
The leaking of early-stage information on new product developments is a phenomenon that fits seamlessly in a long-honoured wind industry tradition whereby OEMs try to protect their crucial data while others – despite a plethora of signed non-disclosure agreements (NDAs) – don’t seem to care.
This applies to internal and external parties alike. Direct competitors, in my experience, are often the first to know of new product developments and are privy to the best information.
OEMs are always at a disadvantage in these complex processes for several reasons. One crucial hurdle they regularly face in protecting secrecy is that installing a prototype requires permitting, and this public administrative process comes with official documentation and announcements and is thus, by definition, hard to fully control.
A second major difficulty facing OEMs is that they must share essential product specifications and details – including on component/sub-assembly sizes and masses – ahead of time with developers, as well as transport and installation contractors.
Crane owners/operators must be made aware of the maximum hoisting mass and lifting height, for example, while transport experts have to assess in advance what equipment to deploy and whether, for onshore, any bridges along the way are capable of carrying the required component masses.
Construction of the ‘SG 21-276 DD’ prototype is hinted to commence this April at the Østerild test site in Denmark. It is likely to use the current location of the SG 14-222 DD prototype, which according to sources is being dismantled.
While a huge installation crane was already installed at the test site last year, the new giant will inevitably fuel the ongoing controversy about offshore turbine sizes, in the context of pledges to ‘end the arms race’ and pause upscaling.
Business as usual
Hardly anybody I met in Bilbao mentioned the ongoing scaling or its pace as a personal or wider worry – similar to concerns about wind exhaustion, but which is now a threat to future offshore wind expansion targets.
It is hard, therefore, to judge whether the wind industry has perhaps decided to ignore both, and at least for the time being concentrate on business as usual and ‘let the market decide’ – as one exhibition visitor put it.
The upcoming ‘SG 21-276 DD’ likely comes with substantially higher specific power compared with most large-scale Chinese competitor offerings equally developed for high-wind IEC I/S offshore conditions.
Mingyang MySE 18-292 (269W/m2) is the first model of the company’s new 18-22MW platform, and even in the highest 22MW mode still has a specific power of only 329W/m2.
At this early product implementation stage, some open questions remain for the as yet unofficial ‘SG 21-276 DD’.
First, when could it become commercially available? Second, how will it align with the current 14MW flagship offering in the ramp-up phase? Third, will the new flagship be a standalone product or the first model of a new turbine platform?
Finally, what is Siemens Gamesa’s long-term strategy for remaining competitive and aligned with growing international competition, including with parties that are not interested in a scaling pause?
Onshore workhorse
Long before GE Vernova began trading as an independent power-engineering company on 2 April, GE introduced without much publicity a 3.X onshore platform expansion with the new 3.6MW 3.6-154 ‘workhorse’ model.
In January the company announced it would deploy 674 units of this new turbine in the SunZia wind project located in a ‘high-desert’ area of central New Mexico state. Once completed in 2026, the electricity generated by the project’s 3.5GW of installed capacity will be transported via a high-voltage direct current (HVDC) cable to Phoenix, Arizona, and from there on to California too.
The 3.6-154 model is apparently so new that as of 3 April it was not yet listed in GE Vernova’s 3.X platform brochure, which incorporates instead a 3.3MW 3.3-154 predecessor or sister product with a specific power rating of only 177W/m2, against a specific power rating of 193W/m2 for the 3.6-154.
The 3.X Platform uses a high-speed drivetrain incorporating an unspecified ‘main shaft with double bearings’ and DFIG. The electrical system is located in the tower base, whereas for instance Nordex and Enercon switched these systems inside the nacelle (up tower), which has also been the long-time standard fitting for Vestas.
Nacelle-based electrical systems offer two key advantages: they enable full nacelle factory pre-commissioning and they reduce electric power transport losses down tower. This benefits especially big turbines with large rotors and high towers because the transport takes place at transformer high-voltage output level.
Electrical systems in the tower base, conversely, enable more compact nacelles with perhaps easier transport and installation logistics.
MW-constrained sites
The new 3.6-154 – similar to Vestas’ V163-4.5 MW (216W/m2) – targets MW-constrained medium- and lower-wind sites with ample land available for wind power development, offering high capacity factors. The main limiting factor under these circumstances is typically the cumulative production capacity that can be absorbed by local grid interconnection points.
On a side note, someone with a fascination for big numbers wrote recently that a western supplier will likely install an 8MW onshore prototype before the end of the year.
No details such as rotor sizes or operating environments were mentioned, which makes the announcement rather meaningless under the persistent widespread practice of expressing wind targets in MWs or GWs instead of productivity per unit in MWhs or GWhs.
Several European suppliers have already announced 175-metre rotors for their latest flagships. An often-quoted limiting factor is the lifting height of available installation cranes.
The 7.0MW Enercon E-175-EP5 E2 (above) for IEC IIA has 291W/m2 specific power, which would increase to 333W/m2 for a (fictive) 8MW. In both cases, any real added benefits depend primarily on the wind climate.
If an 8MW turbine operates in wind conditions of up to 8.5m/s (IEC IIA), there will likely be a substantial number of hours the turbine can produce at this maximum output level, making it perhaps worthwhile depending on the combined numbers.
However, on such a high-wind site, a 7MW variant could achieve more full load hours, thus giving a positive contribution to alleviating the grid congestion constraints increasingly experienced as a result of the ongoing energy transition.
Additional benefits include more stable power production and – through higher capacity factors – a boost in the sustainable use of critical material resources.
Derating option
An interesting discussion is starting in the wind industry on derating given turbine configurations instead of uprating them with unchanged rotor sizes.
Engineering wisdom dictates that derating and/or downscaling existing wind turbine models typically leads to sub-optimised outcomes. By contrast, upscaling leads to a focus on addressing only those components that have become critical and strengthening them.
Another option for boosting onshore wind farm revenues for all types of wind sites is to place turbines on higher towers to raise wind speeds at hub height.
One of several interesting tower developments is a Nordex in-house designed concrete-steel hybrid solution (above) with a current maximum hub height of 179 metres.
The concrete bottom part consists of up to 20-metre long convex segments assembled on-site into full circles and then post-tensioned to a transition piece before mounting the tubular-steel sections.
In November 2023, Nordex installed the first N163/5.X turbines on such hybrid towers but with 168-metre hub height. The technologically similar 179-metre tower variant, with an N175/6.X turbine atop, is planned in Germany for later this year.
The hybrid tower builds on proven concrete tower technology with up to 120-metre hub height that Nordex has used for more than 15 years. The company has a track record of more than 2,500 such towers to date.
.png)
.png)
