Turbines of the year 2019: Offshore turbines

The sector moves into the double-digit MW zone for the first time.

GE’s Haliade-X pushes offshore technology into new realms
GE’s Haliade-X pushes offshore technology into new realms


GOLD GE Haliade-X 12MW

GE’s 12MW Haliade-X direct-drive prototype was installed in the second half of 2019 in the Dutch port of Rotterdam.

This groundbreaking new offshore turbine sets several new wind industry standards.

First is the huge permanent ring generator, with a diameter of around 11 metres.

Second is the rating of 12MW, although the prototype permitting documents refer to 12-14MW, and well-informed sources claim the turbine is already being offered at the 14MW level.

Third is the 220-metre rotor — 218.2 metres according to the permitting documents — a world record in either case.

The 107-metre blades weigh 55 tonnes each, which, with the 600-tonne nacelle mass quoted in the permitting documents, adds up to a total head mass of 850-875 tonnes.

The Haliade-X features a state-of-the- art rotor and generator-rotor support solution that comprises a main bearing unit with a hollow shaft for easy hub service access, and two pre-stressed taper-roller bearings.

The latter is a departure from the "pure torque" solution deployed in the 6MW Haliade, but provides a similar air gap stability levels, according to GE.

The rated rotor speed is 7.81rpm, which for a 218.2-metre rotor diameter corresponds to an 89.2m/s rated tip speed, and represents a good compromise between aerodynamic performance and curbing blade leading-edge erosion risk.


SILVER Siemens Gamesa SG 11.0-193 DD Flex

The latest variation of SGRE’s offshore platform builds on a 1,000 direct-drive track record, with the recently announced upgrade to 11MW already winning a 140-unit contract.

The upgrade narrows the gap to GE’s 12MW Haliade-X, and commercial production is due to start in 2022.

The turbine’s compact "box-type" nacelle enables easier manufacture and transport. Other features include an enlarged generator and 94-metre rotor blades made from C&GFRE.

A key overall objective was creating an optimal setup for utilising the existing mature supply chain, with additional cost savings through reuse of SGRE’s blade and nacelle factories.

The 11MW turbine has a specific power rating of 376W/m2, against 365W/m2 for the current SG 8.0-167 volume product, both designed for high-wind North Sea applications.


BRONZE Dongfang D10000-185

The typhoon-resistant direct-drive D10000-185 for high wind and IEC I/S has a 185-metre rotor diameter and was the first 10MW Chinese turbine to be announced.

The fully enclosed outer-rotor generator operates at 3.15kV medium-voltage level, against the wind industry’s semi-standard of around 1kV.

Together with IGCT-based power electronics , this offers an efficiency improvement of 1-3% compared to low voltage, claims Dongfang.

The 10MW design builds on a 1,200-turbine onshore direct-drive track record, encompassing 3.XMW and the latest 4.XMW platforms.

The in-house manufactured blade features carbon in the structural main beam for a favourable 34-35-tonne mass for a 90-metre unit designed for IEC I (S) loads. Eight pre-series turbines are planned for 2020, with the next envisaged scaling step taking the machine to 12-15MW with a 230-metre rotor.

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