New technologies ensure demand for wind generation remains high

Paul Boughton

Demand for wind generators remains high, particularly as new technologies can be optimised for lower-wind situations. Sean Ottewell reports.

In February, Alstom Renewable Power signed a memorandum of understanding with leading Brazilian wind power provider Renova Energia to supply, operate and maintain around 440 onshore wind turbines in Brazil worth in excess of EUR1billion.

Ranging from 2.7-3MW each, these turbines will represent a minimum of 1200MW new wind power generation capacity. They will equip Renova's wind farms in the state of Bahia and will be delivered from 2015 onwards, over an estimated period of three to four years.

Alstom's ECO 100 3MW onshore wind turbine range was selected as one of the most proven machines on the market, with turbines running since 2008. It offers high yield and leading efficiency across all wind classes, with its rotor diameter from 100-122 metres. This allows developers to select the best rotor for every position. The combination of two or even three models of the range (ECO 100, 110, or 122) within the same wind site optimises the capacity factor of a project while reducing the balance-of-plant cost.

Renova Energia carried out a thorough process for the selection of the manufacturer, using 'clean sheet' cost assessment model and comparative analysis.

"Alstom presented the best combination of price and technical performance, allowing for greater competitiveness in our projects, said Mathias Becker, ceo of Renova Energia. "This will allow for increased efficiency of our plants, as we will have a more adequate technology to our winds, and reduced investments, which are key for us to maintain our leadership position in the increasingly competitive wind market," he added.

The wind turbines will be manufactured at Alstom's unit at Camaçari in the state of Bahia. Opened in November 2011, the plant will see its manufacturing capacity grow from 300-600MW/y of generating plant as the project gathers pace.

Also in South America, Nordex USA has concluded an agreement with Usinas y Trasmisiones Eléctricas (UTE), Uruguay's state power company, for the sale of 28 of its N117/2400 wind turbines for the Juan Pablo Terra wind farm. Nordex, a leading global manufacturer of utility scale wind turbines, will be responsible for delivery, installation and commissioning and for ongoing maintenance for a minimum of 10 years under a premium service contract.

The site, on the border with Brazil, is located a few miles from the city of Artigas, in the north of Uruguay, about 370 miles from Montevideo, the capital city. This will be largest wind farm owned by UTE and represents the country's commitment to the growth of renewable energy. Delivery of turbines will begin next February, with project completion due the following June. [Page Break]

The newest addition to Nordex' established multi-megawatt fleet, the N117/2400 is designed specifically for light wind regimes, maximising the power produced at sites where wind resources were previously considered unsuitable for wind energy (Fig.1). The turbines, on 91metre towers, are particularly well-suited to the site. Each of the 2.4MW turbines will be capable of powering about 3500 Uruguayan homes.

"We are honoured that UTE has chosen Nordex and our technology for this important project. Uruguay's first wind turbine was a Nordex N27/250 installed in 2000 for UTE as customer and still running successfully today," noted Ralf Sigrist, president and ceo of Nordex USA. "Our company has always been recognised for its engineering expertise and leadership and this is exemplified by the changes in size, productivity and competitiveness that we have achieved over the past decade."

Nordex has also received its first contract for the delivery and installation of a wind farm complete with Generation Delta turbines - from Raahen Tuulienergia in Finland.

The two N117/3000 turbines, which will be fabricated and installed this year, each have an output of 3MW.

The site is located in the port area of the Northern Finnish town of Raahe which is characterised by wind speeds of over 8metres/s. This calls for turbines able to generate the greatest possible yield in medium wind conditions.

Nordex is assembling one turbine on a 91-metre and the other on a 120-metre steel tube tower. Thanks to the large rotor sweep of the N117/3000, its nominal output and the tall towers, the wind farm will achieve an annual yield of around 20 millionkWh of clean electricity, equivalent to a capacity factor of 38 per cent. As the site experiences periods of extremely low temperatures of down to -30°C, Nordex will be supplying cold-climate versions of the turbine. In addition, the sound power produced by the turbines will not exceed 106 dB.

"This contract underscores the great confidence which our customers have in our reliable technology and in the new higher yields which we have achieved in strong and medium-wind locations with Generation Delta," says Nordex management board member Lars Bondo Krogsgaard.

Heikki Jäälinoja, ceo of Raahen Tuulienergia and Raahen Energia said, "Nordex' global record for reliability, efficiency and service has been crucial for our decision to choose the N117/3000. This turbine is a perfect match for the wind regime at the Raahe harbour and we are very happy to be able to use newest technology to maximise the energy output at the site. Based on our experience of the professional negotiations we are looking forward to continuing to work together with Nordex also in future."

In January, Vestas announced that it had signed an agreement to supply towers for a number of non-company wind power projects over the next two years.

Vestas is implementing its plan to create a more flexible and scalable business to adapt the company to the uncertain market situation in the wind industry. Part of this plan is to more effectively use the existing production capacity. This new agreement is a step in securing this.

The agreement means the company will ramp up at its tower factory in Pueblo, Colorado, USA. Vestas soon will begin manufacturing the first part of the third-party tower supply agreement that could use up to 25 per cent of the production capacity. The agreement will create more than 100 jobs by this summer.

Also in January, the company announced a three-year extension from Alliant Energy to provide service and maintenance for 121 V82-1.65 MW wind turbines at the Whispering Willow Wind Farm East in Iowa, USA.

Under the agreement, Alliant Energy chose the active output management (AOM) 2000 service option. This consists of scheduled maintenance and VestasOnline, a surveillance system that allows Vestas to monitor and remotely control the turbines to ensure the turbines are running optimally (Fig.2).

Vestas has performed service and maintenance at Whispering Willow Wind Farm East since the site began operations in 2009. The wind power plant can produce enough electricity for about 50,000 households.

"Our company is pleased to partner with Vestas to extend our service and maintenance agreement for our 200 MW Whispering Willow Wind Farm East," said Tom Aller, senior vice president of energy resource development at Alliant Energy. "Renewable energy is a key component of our long-term energy resource supply. As a result, we need a company that can keep our wind generating facilities operating at an optimum level. Vestas is an industry leader in servicing and maintaining wind generating facilities."[Page Break]

Hydraulic drive train tests get underway

Mitsubishi Heavy Industries (MHI) has commenced test operation at its Yokohama dockyard and machinery works of a large-scale wind power generation system that adopts a hydraulic drive train in place of the earlier gear-driven system.

The test operation is a part of the project launched in September last year to develop a hydraulic drive train system for offshore wind turbines. The effort is supported by Japan's New Energy and Industrial Technology Development Organisation (NEDO).

According to MHI, the event marks a world's first operation of a large-scale hydraulic drive train type wind power generation system applying the company's Digital Displacement Transmission technology. Leveraging the test results, MHI will accelerate its development of an offshore wind power generation system in the 7MW class, with installation and operation slated to begin at Hunterston, in the UK, this year. A mass-produced commercial model will be targeted for market launch in 2015.

The system recently inaugurated in Yokohama is based on an existing MWT100 gear-driven wind power generation system that was retrofitted with the new hydraulic drive train. The retrofitting involved replacement of the step-up gear - which functioned as the power transmission system to increase the rotation speed of the rotor (10rpm) to the rotation speed of the generator (1000rpm) - by the Digital Displacement Transmission hydraulic drive train.

MHI developed the new hydraulic drive train, with support from NEDO, based on the digitally controlled hydraulic technologies of Artemis Intelligent Power, a UK-based venture company that it acquired in 2010.

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