Feature

New turbines' boost to energy yields


Gail Rajgor

As ever, this year’s European Wind Energy Association (EWEA) exhibition played host to the launch and/or presentation of new turbines, components and ancillary services by key players in the market. In terms of turbine design, arguably the highlights came from Nordex, GE, NGentech and Siemens, although not necessarily in that order.

This article is taken from the forthcoming issue of Renewable Energy Focus magazine (March/April 2013 issue). To register to receive a digital copy click here. (Note - free of charge to qualifying individuals).

A new generation of onshore machines

Germany’s Nordex took the wraps off its fourth generation turbine, which it says achieves an additional yield of up to 31% at locations with medium (IEC2) and strong (IEC1) wind speeds.

With this in mind, the company will particularly be targeting wind markets in the UK and Ireland, Scandinavia, France, Turkey and Northern Germany, broadening its existing Generation Gamma range with the addition of highly efficient systems for windy locations, it said.

“We have reached a new stage of evolution based on our proven multi-megawatt technology,” said Dr. Jürgen Zeschky, CEO of Nordex SE. “Our foremost goal was to lower the electricity production costs.” Significantly, just a day into the EWEA show, the company received its first order for the new Generation Delta turbines from Raahen Tuulienergia Oy in Finland.

There are two turbines in the range so far. For medium wind speed sites, the 3MW N117/3000 provides a 20% increase in nominal output over its predecessor. Designed for high wind speed locations, there’s the 3.3MW N100/3300 unit, which Nordex says gives an increase in nominal output of more than 30%.

The higher nominal output of these turbines has a positive effect on energy yields. “Yet, despite this substantial increase in output, sound power levels have remained stable in both wind classes.”

At the same time, substantially larger rotors are being used in both wind classes. The rotor diameter of the N117/3000 has grown by 17m, resulting in an increase of around 37% in the rotor sweep and significantly higher efficiency with around 10% higher number of full load hours, the company added. The N100/3300 meantime has a rotor diameter ten metres larger than its predecessor, driving the swept area of the rotor up by 23% and contributing to even higher energy yields.

The Generation Delta’s turbines come with taller hub heights per wind class, enabling “additional gains in annual energy production and opening up complex forested sites for wind turbine installations”.

In fact, Nordex is offering a steel tube tower with a hub height of 120m for medium wind-speed locations for the first time - the N100/3300 is available on a steel tube tower with a hub height of 100m. With its larger rotors, increased nominal output and optimised technical systems, the new Generation Delta turbine range is, the company claimed, “setting new standards in terms of economic efficiency, reliability, serviceability and safety”.

The range also means Nordex “has improved its product offering substantially” for cold regions. Both new turbines classes feature the firm's anti-icing system for 58.5m rotor blades. “This is a first for strong-wind locations,” the company stressed. “As a result, Nordex customers are able to rely on secure yields from their wind turbines and maximum availability in low-temperature regions.”

Serial production and delivery of the Generation Delta turbines will begin from 2014, although initial projects involving both turbine designs are expected to being installed from mid 2013 – Nordex estimates eight turbines will go up by June.

At the EWEA show, Nordex signed its first contract involving the range – for the supply and installation of two cold climate versions of its N117/3000 turbines in Finland. The units will be installed in the port area of the Northern Finnish town of Raahe, characterised by wind speeds of over 8m/s and periods of extremely low temperatures of down to minus 30 degrees Celsius. One turbine will be assembled on a 91m tower and the other on a 120m tower. An annual yield of around 20 million kWh of electricity is expected, equivalent to a capacity factor of 38%.

A “Brilliant” machine

Sure to get the eye amongst headline writers, GE's star of the show in Vienna was its new 2.5–120 Brilliant Wind Turbine, announced to the market just days before the EWEA event kicked off. “Our 2.5–120 is the first wind turbine that utilises the industrial Internet to help manage the intermittency of wind, providing smooth, predictable power to the world regardless of what Mother Nature throws its way,” said Vic Abate, (former) vice president of GE's renewable energy business in a statement on 31 January 2013. “Analysing tens of thousands of data points every second, the 2.5–120 integrates energy storage and advanced forecasting algorithms while communicating seamlessly with neighboring turbines, service technicians and customers.”

While the latest designs in Nordex's range are for medium and high wind speed sites, the GE machine is specifically designed for the other end of the spectrum. “The 2.5–120 is the first wind turbine to bring together world-class efficiency and power output at low wind speed sites, capturing a 25 percent increase in efficiency and a 15 percent increase in power output compared to GE's current model.” The rotor is 120m enables greater output in low wind speed sites while a taller tower, which has a maximum hub height of 139m, makes it suitable for heavily forested regions in places like Europe and Canada.

Peek into the future

Amongst the other exhibitors, NGenTec Ltd showcased its hybrid and direct drive permanent magnet generator designs (PMG) for MW-scale wind turbines (featured on page 20of the July/August 2012 issue of Renewable Energy Focus).

The strength of NGenTec”s generator is in its “unique modular design that leads to high operational flexibility and simplicity of in-situ maintenance on the PMG”. The generator”s compact, lightweight and standardised component structure will offer its customers greater availability, lower O&M cost and ease of manufacture and transport, which overall result in a quantifiable lower cost of energy, the firm said.

Following on from the successful build of the full scale 1MW prototype by NGenTec during 2012, the generator was tested extensively over a seven month period, with the results meeting or exceeding all design expectations. Garrad Hassan (GL-GH) conducted a comprehensive simulation of the NGenTec hybrid in a large offshore wind farm comparing it with the state of the art, and confirmed that the benefits of the technology are “substantial”.

Dr Makhlouf Benatmane, Chief Executive Officer at NGenTec said: “For NGenTec, 2013 will provide the key milestone of signing our first agreement with Original Equipment Manufacturers (OEMs). The deal is likely to be focused around our differentiating hybrid technology where we have already experienced substantial interest from multiple potential customers.”

4MW offshore design

For the offshore wind market, visitors to the EWEA show had Siemens Energy to satisfy any cravings for new machines. The company launched its new 4MW offshore turbine which has a rotor diameter of 130m.

“The advancements designed into the SWT 4.0–130 increase energy capture by up to 15 percent over our best-selling SWT 3.6–120 type”, said Henrik Stiesdal, Chief Technology Officer at Siemens' Energy Sector's Wind Power Division.

The nacelle and tower are advanced variants of the 3.6MW wind turbine design. The rotor blades are manufactured using its proven IntegralBlade process, cast in a single piece without use of adhesive bonding. “The new B63 rotor blade, measuring 63m in length, is the longest and technologically most advanced blade in the 4 megawatt class.” In fact, the B63 sweeps an area equivalent almost to the size of two football fields, the company said.

“Thanks to optimised coupling of blade bending and twisting, these aeroelastic blades react more flexibly to high wind loads, absorbing forces similarly to the cushioning effect of shock absorbers on cars. This technology allows use of longer rotor blades, which boosts wind power capture and thus increases unit performance.”

A prototype of the SWT 4.0–130 is operating at the Osterild Test Center in Denmark. Serial production is expected to start in 2015.

About: Gail Rajgor is Managing Editor of Renewable Energy Focus.

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