Conference programme

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Friday, 20 November 2015
12:00 - 13:30 The O&M impact on LCOE – How to get costs down?
O&M & logistics  
Onshore      Offshore    

Room: Montparnasse

This session shall focus on the challenge of reducing the Cost of Energy from wind parks through intelligent O&M.
What can be done from a Life Cycle perspective to ensure the O&M costs are minimised in respect to the highest possible RoI for investors?

The session will be devided in two parts: the first part will feature five presentations about opportunities and practical solutions for O&M cost reductions; in the second part four leading wind turbine manufacturers will share their experiences and outline their strategy to achieve cost reductions in O&M .

Please note that the session will be extended by 15 minutes and will therefore finish at 13:45 instead of 13:30.

Learning objectives

  • Be able to identify the Total Cost of Ownership for a Windfarm
  • Enable the attendees to suggest cost improvements at different project stages
  • Enable Attendees to verify and measure the impact of suggested improvements
  • Create understanding of a common industry reporting tool for failure rates
  • Learn about O&M challenges from leading wind turbine manufacturers
Lead Session Chair:
Wei He, Statoil, Norway
Simon Watson, Loughborough University, United Kingdom
Christensen Niels Kaas KK Wind Solutions, Denmark
Rasmus Nielsen (1) F
(1) KK Wind Solutions, Ikast, Denmark

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Presenter's biography

Biographies are supplied directly by presenters at EWEA 2015 and are published here unedited

Niels K. Christensen holds a Master Degree in Mechanical Engineering and Energy Conversion. He has been working in sales for 30 years in different industries. The past 8 years he has been with KK Wind Solutions A/S and has been responsible for sales of wind turbine control systems in Europe and Americas. The last 2 - 3 years he has been focusing on Control Retrofit and Upgrades to lower O&M costs and increase energy production for wind turbines.


Improving performance and lowering operational cost through control system upgrade


Rapid development in electronics and control systems provides new opportunities for operation of wind turbines. Retrofitting older turbines – which make up a considerable share of the world’s installed capacity – with a modern control system provides significant improvements in relation to remote monitoring, control and root cause analysis for the turbine owner.


This abstract describes the development and subsequent field installation of control system retrofit solutions on Vestas V47 and Bonus 1.3 MW turbines on site as well as the performance improvement documented after the commissioning.

Main body of abstract

With a considerable part of the world’s installed capacity consisting of turbines older than 10 years - 25 percent in EMEA, for example - there is a great potential for improving output and lowering cost of energy on the existing fleet of wind turbines.

The majority of the cost during a turbine’s lifetime is related to operation and maintenance – and owners of earlier generation turbines face a number of particular challenges. These include:
• limited access to spare parts
• limited remote monitoring and control
• low availability compared to newer turbines.

With 25 percent of turbine failures related to the electrical system, the arguments for retrofitting a turbine’s control system are clear: Lower O&M cost and optimised turbine performance both in regards of availability and energy production without compromising safety and quality.

With rapid evolution within electronics and control systems, vast new opportunities for controlling machines are available today. Introducing modern control platforms for older turbines can make operation and maintenance more effective and less resource-demanding, while extending the lifetime of the turbine. A modern control system also provides owners and maintenance with the data needed to perform root cause analyses of recurring problems, rather than ineffective work-arounds.

Working with a customer to retrofit turbines on site in the USA, KK Wind Solutions has carried out a root cause analysis into why the number of yaw motor errors was high on the Bonus 1.3 MW turbine. This resulted in a software change which halved the yaw activity from 165,000 starts per year in the original control system without any penalty of additional yaw misalignment. This means less wear and tear and hence longer lifetime of the components.

Another frequent fault on the Bonus 1.3 MW turbines was related to pitching. The original pitch control electronics was first generation technology which have tendency to drift, so that the pitch angle does not follow the set point. This results in pitch tracking errors and consequently reduced availability. It also leads to the optimal pitch angle not being used, causing suboptimal power production. By upgrading to 3rd generation pitch control electronics, more than 90% of the pitch tracking errors have been eliminated.

Field data from the project show how the power curve, too, can be improved with a control system retrofit. A wind turbine’s control system can influence the power curve through the control of pitch and yaw. Vast technology improvements have been made over the past decades in both areas and an upgrade can make the most of these advancements. This includes applying modern sensors and control algorithms. Upgrading the turbine’s service interface can also lead to a power curve improvement by making the calibration procedures of both pitch and yaw more simple and intuitive, providing a higher probability of a optimal calibration.


Although retrofitting a control system is a technical challenge, the benefits are clear: Improved turbine performance both in terms of availability and power production by upgrading to modern, wind-specific technology. Typically, this will lead to a business case with payback in less than three years.

Learning objectives
The project’s aim has been to develop and field test control system retrofit solutions that ensure higher yield from existing turbines which make up a considerable share of the world’s wind power capacity.