Turbines of the Year 2020: Offshore turbines

Strong showing from Chinese manufacturers as established players focus on 10MW+

Nezzy2 scaled prototype… Radical concept on the way to becoming reality (pic: Jan Oelker/aerodyn)
Nezzy2 scaled prototype… Radical concept on the way to becoming reality (pic: Jan Oelker/aerodyn)


GOLD Scaled 1:10 aerodyn-engineering Nezzy2

Clever out-of-the-box thinking, skill and determination led to the 1:10-scale fully integrated Nezzy2 floating concept — featuring two closely interspaced counter-rotating downwind rotors — to successfully complete testing and validation, Windpower Monthly reported in June 2020.

When aerodyn-engineering founder Sönke Siegfriedsen presented his radical 15MW concept in 2017, he hoped “to realise a market-ready floating power plant by 2025 or earlier”.

The scaled Nezzy2 project timeline from November 2019 until October 2020 involved prototype design and manufacture, bench tests, and inland-lake and Baltic Sea testing with two- and three-bladed rotors.

Nezzy2 is fitted with 180 sensors for system behaviour verification. The validation of the measuring data was aligned with the calculation results, says Siegfriedsen. Nezzy2 further showed what he calls “calm swimming stability” under scaled hurricane conditions with 3-metre wave heights — equivalent to 30-metre waves at full scale, together with a favourable maximum inclination of six degrees.

In August 2020, certification body DNV GL awarded Nezzy2 a statement of feasibility, involving evaluation of all technical systems and solutions. This gave the company the confidence to proceed with full-scale installation.

EnBW is co-financing this development. The German utility has secured the licensing rights for Europe and the US, and will work with aerodyn on the further development. EnBW earlier carried out a comprehensive scan focused on five areas: technology readiness; risk and requirements; Capex with structural mass a key indicator; Opex; and port capability including (de-)installation and cable connection. Nezzy2 is at technology readiness level 5.

SILVER GE Haliade-X 13MW

GE’s 12MW–14MW Haliade-X direct-drive prototype became operational in November 2019 at the port of Rotterdam’s Tweede Maasvlakte industrial area. In October 2020, the US supplier announced the prototype had been optimised to a 13MW power output.

This makes it the world’s most powerful operating turbine. The uprating with unchanged 220-metre rotor diameter should generate 4% more energy compared with its 12MW predecessor, assuming near-maximum 10m/s mean wind speeds for IEC IB.

GE said in October 2020 that the release of a type certificate was due “in the coming months”. Serial production is scheduled to start in the second half of 2021 in Saint-Nazaire, France. An uprated 14MW version was announced in December.

BRONZE Siemens Gamesa SG 11.0-200 DD Flex

The 11MW SG 11-200 DD (350W/m2) represents a further step forward for SGRE’s direct-drive offshore models since the launch of the SG 8.0-167 in late 2017.

The first major evolutionary scaling step was the 10MW SG 10-193 DD (1/2019). The SG 11-193 upgrade with 10-11MW flexible ratings followed ten months later, with the SG 11-200 DD and SG 14-222 DD announced in March and May 2020, respectively.

The SG 11.0-200 DD upgrade with ramp-up scheduled for 2022 is an important intermediate model that further narrows the gap with GE’s Haliade-X. Firm orders and preferred supplier agreements for 2.6GW have been made. SGRE has an impressive total of more than 1,000 direct-drive turbines, with a next-generation SG 14-222 announced.

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