BEST IN CLASS
The Chinese manufacturer's low and ultra-low wind speed flagship comes with a large rotor diameter of 140 metres and flexible power rating of 3.0-3.4MW. The turbine is an evolution of the 2.5MW Vensys 90/100 series, introduced in 2007-08, and its 3MW successors. Goldwind is Vensys' main shareholder and technology licensee.
Technology features include an in-house outer-rotor PMG with integrated cooling system, a single rotor bearing and an ingenious patented "maintenance-free" pitch control system with toothed belt drive.
The original drivetrain design on the Vensys 90/100 was aimed at substantially reducing head mass (nacelle and rotor), and bringing that mass in line with its new geared multi-megawatt competitors. This was achieved through a series of technology measures including the use of a single rotor bearing and a relatively lightweight generator. Two 3.4MW prototypes are reportedly operating in China, and the company claims 1.6GW in orders.
2 Senvion 3.6M140 EBC
Introduced at Husum WindEnergy 2015 as a 3.4MW turbine with a then-record-setting rotor diameter of 140 metres, Senvion is now testing a 3.6MW prototype in Germany.
The 3.6M140 builds on the proven principles and experiences Senvion pioneered with the 3.4M104 in late 2008.
The 3.6MW model features a non-integrated three-point gearbox support and induction generator plus full converter. The Eco Blade Control (EBC) utilises advanced load-based individual pitch control technology, and the in-house developed 68.5-metre blades come without carbon. The next upgrade — a 3.7MW turbine with a 144-metre rotor diameter — is being developed, with a prototype planned for mid-2018 and a firm 116-turbine order in Australia already in the book.
3 Lagerwey L136-4.0-4.5MW
The direct-drive L136 is a genuine lightweight with a head mass of under 300 tonnes, including "standard" LM blades without carbon. The structural design could accommodate a 150-metre-plus rotor for IEC IIIA operations, but a prototype to this specification is not expected before 2019.
The compact drivetrain comprises an in-house main bearing solution, semi-integrated with a passive air-cooled inner-rotor PMG with an outer diameter of 5.0 metres. Elimination of a separate stator housing allows effective generator heat dissipation to the exposed stator directly facing outside wind-flow.
The L136 will be available in a "quiet" 4MW form, and in 4.5MW-plus specification for sites without noise restraints. Lagerwey also offers in-house modular steel towers for hub heights up to 166 metres.