More green energy from the same amount of resources

28 June 2018
The lifespan of wind turbines can be extended cost-efficiently – especially on offshore farms, where turbine lifespan can potentially surpass the usual 20-25 years.

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Wind Energy

Planning and constructing offshore and onshore wind farms is a complex task. It requires technical excellence and a multi-disciplinary approach. Read more about our services within wind energy. 

Smarter calculations can cut offshore wind costs further

To optimise the design of wind foundations and turbines, engineers need a platform for fast, robust and cloud-based data storage and execution. Ramboll has teamed up with Google Cloud to improve its in-house wind software in this area. Read the article here.

By Michael Rothenborg

Offshore wind farms have to be much more robust than onshore ones, especially because wind, waves and salt corrosion have such a heavy impact. Conditions like these put stress on the constructions and cause fatigue – and the structural materials eventually wear out. 

Consequently, the world’s first offshore wind farm, Vindeby, built near Lolland in Denmark in 1991, has just retired its turbines. And all around the world similar decommissioning projects are approaching, as offshore wind turbines typically have a service life of just 20-25 years. But it does not have to be this way, emphasises Lisa Ziegler
from Ramboll (pictured). She has won three prestigious international awards for her PhD study “Assessment of monopiles for lifetime extension of offshore wind turbines”, including Best Paper at the International Conference on Ocean, Offshore and Arctic Engineering 2017. She will be submitting her PhD to the Norwegian University of Science and Technology later in 2018. 

A minimum number of sensors 

Around 2010 the industry started installing larger wind farms with turbines from the multi-MW class – these are the turbines whose lifetime could be cost-effectively extended.“The service life of wind turbines is 20-25 years, but very often the assets have structural reserves left. Extending the lifetime of wind turbines can increase wind farm profits – and enable more green energy to be generated from the same amount of resources. This lowers the cost of wind energy as well as the environmental impact of generating it. Our research paves the way for lifetime extension to become common practice just as in other industries,” Lisa Ziegler points out. 

A crucial part of her PhD is to analyse methods that can be used in lifetime extension assessments – and to investigate how they can decrease the risk involved in making lifetime extension decisions. Her work resulted in a novel concept for monitoring fatigue loads on the support structures of offshore wind turbines – a monitoring system that only requires a minimum number of sensors. 

Dismantling onshore wind turbines 

The lifespan of onshore wind farms can be made more sustainable too. The German Federal Environment Agency (Umweltbundesamt) has launched a 19-month project to develop a circular economy approach for dismantling end-of-life onshore wind turbines. 

The agency has commissioned Ramboll to gather and assess data for creating policy approaches concerning the management and reuse of waste materials generated during the end-of-life dismantling process as well as to provide feedback to manufacturers. The team will, for instance, conduct a survey to establish the current status of onshore wind turbines and the practices used to dismantle them, and will evaluate the associated waste streams (which contain carbon fibre components, gearboxes, lubricants and permanent magnets, etc.).

This will help inform the future design of more suitable wind turbine components.

Ramboll Group A/S

Ramboll Group A/S
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