Turbines of the year -- Onshore turbines 3MW-plus

WORLDWIDE: Fast-growing market sector as manufacturers concentrate their efforts on low wind solutions

Shhh… Nordex N131/3000 ofers low noise and a large rotor for high yields and reduced cost of energy


GOLD Nordex N131/3000

With a 131-metre rotor diameter that represents a new 3MW class benchmark, the N131/3000 low-wind IEC IIIA turbine completes Nordex's new Delta platform.

The turbine's specific power rating of 223W/m2 is similar to that of the successful N117/2400, and is again aimed at offering high yields and the lowest possible cost of energy at low and medium wind (inland) sites. Another major benefit to this model is its low sound power performance of 104.5dB(A), which compares with a more usual 108dB, and which will allow for enhanced permitting and site integration.

Technologically, it builds on the N117/3000 and N100/3300 Delta sister models in sharing a high-speed modular drivetrain layout with three-point gearbox support, double-fed induction generator (DFIG) and partial converter. The key component is the slender new in-house developed 64.4-metre rotor blade, which builds structurally on the lightweight blades fitted to Nordex's N117/2400, similarly incorporating carbon in the blade's load-carrying structure. One difference is the very slender shape towards the blade tip, and a maximum width with "flat-back" airfoil now extending further towards the root to maximise energy and curb blade loading.

For Scandinavian markets offering easy boat access, Nordex develops towers with 210-metre total installation heights.

Nordex has already taken its first order, for a community project of 24MW, and as the magazine went to press, the prototype was being installed in Northern Germany.

SILVER Enercon E-101

The 3MW class is a main pillar under Enercon's future growth strategy, boosting the E-101 track record to almost 800 units by the end of November 2014. The E-101 incorporates a new-developed water-cooled electrically excited synchronous generator.

Blade manufacture takes place at a new advanced multi-storey facility. It contains in-house developed mobile production platforms that work in seven predetermined process steps of ten hours each, transporting two matching blade halves in parallel over a 500-metre rail system. Enercon claims cycle time reductions of 20% and more compared with conventional blade manufacturing.

It is available with record hub heights up to 149 metres, matched with in-house prefab concrete-steel hybrid tower technology. An E-101 high-wind IEC class I model version will be available from 2016.

BRONZE Acciona AW116/3000

The first prototype of Acciona's 3MW turbine family was installed in 2008 and the company has continued to evolve the platform since then, adding the AW116/3000 model in 2011 with the AW132/3000 expected on the market in 2016.

The series comprises a non-integrated high-speed geared drivetrain with the main shaft supported by two bearings, and a 12kV double-fed induction generator. This voltage level might eliminate a medium-voltage step-up transformer for wind projects near the project substation.

An interesting innovation is that the AW116/3000, AW125/3000 and AW132/3000 models all have structural inner blade segments that are of similar size and design and with interchangeable tip sections which allows for varied length.