Extending the operational life of your assets – thinking about it early

Introduction

Wind turbines are designed for a specific lifetime of 20 years. Extension of the operating life can be highly interesting for operators, investors and manufacturers in order to maximize the profitability of their wind farm. What needs to be done to extend the operational life of a turbine or a wind farm ?

Approach

In March 2016 DNVGL has released its new standard for lifetime extension offering different methods to extend the lifetime of wind turbines. The DNVGL standard provides guidance on the technical assessment for lifetime extension. Thinking about lifetime extension already at an early stage and developing adequate concepts is useful, as financial planning becomes more reliable when technical questions have been solved.

Main body of abstract

Operation of a wind farm beyond its design lifetime presents both opportunities and risks for a project. Assessing a wind farm with regard to a possible extension of lifetime from a technical point of view helps to reduce uncertainties for the operation beyond the original design lifetime.
Extending the lifetime of a turbine is a complex engineering task, as wind turbines are subject to high dynamic stresses. The assessment for lifetime extension primarily focusses on all fatigue related issues - all load transferring components need to be evaluated in this regard. Today’s design practice needs to be taken into account for the assessment, as knowledge has significantly increased over the years.
Experience shows that the database for the evaluation of a turbine’s potential to extend its lifetime can be very different. Site-specific information, turbine-type related experience, accessibility of design documentation are important aspects affecting the quality and quantity of information and are influencing the approach.
Taking into account the experiences from lifetime extension projects gained in the past years, DNV GL has further developed its approach that has been introduced into the market already in 2009. Different methods can be applied within the lifetime extension assessment – guidance is provided in the new Standard DNVGL-ST-0262 ‘Lifetime extension of wind turbines’.
The methods described help to optimize operation costs, as measures like specific lifetime extension inspections, monitoring or component exchange can be tailored to fit to the needs of the specific wind farm.
A realistic assessment of a wind farm’s potential for lifetime extension is important information not only at the end of the design lifetime. Operators should start thinking about lifetime extension already at an early stage. Relevant data can be collected and – depending on the concept – specific monitoring may need to be performed in order to have a sufficient data base delivering the input for the lifetime extension assessment.


Conclusion

How to extend the lifetime of a wind turbine is a question extensively discussed in wind energy branch.
The new standard for lifetime extension published by DNVGL provides guidance on how to extend the lifetime – considering the needs of operators as well as manufacturers.



Learning objectives
Delegates will get an overview about different pathways to extend turbine’s lifetime. They will get to know tailored solutions for extending the lifetime of their assets. Operators of single wind turbines and of big wind farms as well as manufacturers and energy suppliers are addressed by the new DNVGL Standard.