23 February 2017

Small wind turbines: navigating the ‘jungle’

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While large scale wind turbines gather momentum, the installation of smaller ones in Europe is progressing very slowly. One of the major problems is the lack of certified machines. Turbine producers are put off by the high costs of the certification procedures

Most EU countries enforce a legal obligation to only use wind turbines certified by an accredited organisation. But there are differences between those turbines connected and those not connected to the electricity grid and, in reality, what is required by law and what is actually happening are at odds in some cases. Furthermore, the actual pieces of legislation only involve turbines with a horizontal axis.

"The basis of this legislation is the international standard IEC 61400-2. Several countries also apply additional national guidelines," says Koen Broess, innovation consultant at DNV GL in the Netherlands. His company is one of the consortium partners in the European research project SWIP, which aims to promote the development of small scale wind turbines. "But as long as the market for small wind turbines remains small, it is unprofitable for producers to take on the expenses for the certification procedure. Currently, most small wind turbines aren't certified."

Broess is convinced that certification, independent of the legal obligation, is a favourable factor in a competitive market, because "it creates trustworthiness”.

"To make small wind turbines profitable, location is another factor to consider carefully. The local circumstances have a high influence on the performance of a wind turbine and on the loads it has to endure,” he adds.

"The route towards certification is a disastrous one," says Sander Mertens, founder of small wind turbine producer Windchallenge (Rotterdam, Netherlands). He estimates it will cost his company about 50,000 to 100,000 euro. "It is important to wait until the last possible moment when your final turbine design is complete. Once certified you can't change any component anymore, otherwise the complete certification procedure has to be redone."

Test results from real operational situations are important for finalising the design. "The number of demo and research sites where several turbines can be compared in equal circumstances is limited. Fortunately, the Dutch laws allow us to install uncertified turbines in some specific areas," explains Mertens. "Without this permission, it wouldn't be possible to obtain enough operational measurements."

Despite his objections, Mertens is determined to certify his turbines. "It can provide you with a competitive advantage, especially on the international market. The large production companies already have their machines certified, as for them the costs are negligible. We need the certification to show buyers a path through the jungle and to distinguish us from the many cowboys on the market. However, those cowboys are very cunning. They can always show one certificate or another, attached to individual components. Lots of buyers don't see that there is no certificate for the complete turbine."

Mertens is thinking about alternatives for certification. "In the Netherlands, our branch organisation NWEA is thinking about a kind of sector label. But for young and small producers even this would be too expensive to obtain." Mertens proposes a CE-based system. "This way, producers indicate that they follow the legal standards. Anyone can investigate whether they really do so. Because this way no paid efforts by certification organisations are needed, the producers have no costs for the mark, but malicious producers risk high penalties when discovered."

"There are other ways to avoid peak certification costs," explains Joannes Laveyne, energy researcher at Ghent University in Belgium and spokesman for Windkracht 13, a test and demonstration project for small and middle scale wind turbines in Ostend. "Organisations such as ours are commissioned by private companies to test their turbines in real life situations and to compare their performance with publicly available data from existing operational turbines. Our work prevents them from having to execute expensive, unsuccessful certification procedures."

"Of course it is necessary to certify all wind turbines," states Peter Flower, who is in charge of wind turbine certifications at DNV GL in Denmark. "Besides European and national laws, some local authorities also require it. Banks want to see certificates before they give a loan to wind energy investors and insurance companies ask them to be informed about safety risks. Buyers are eager to see information about a turbine’s performance in the certificate, as they experience the information provided by the producers is often far too optimistic."

"I don't think the lack of certification is the main problem for small wind turbines," Laveyne argues. "The introduction of a new type of small wind turbine is a very rare event. Older types still are being sold. The main problem in urbanized areas is to obtain permission to install them. Whatever safety guarantees are embedded in the certificate, neighbours and even local authorities maintain their distrust and make objections against the applications to install wind turbines."

These challenges are also faced by the SWIP project. The consortium is redesigning small wind turbines to reduce noise, turbulence and vibration in a bid to increase their use in cities.

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