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ECN publication
RVO lifecycle and decommissioning offshore wind
Published by: Publication date:
ECN Wind Energy 21-3-2016
ECN report number: Document type:
ECN-E--16-009 ECN publication
Number of pages: Full text:
33 Download PDF  

"In this desktop study ECN explores three end-of-life options for offshore wind farms: lifetime extension, re-powering and decommissioning. Combining a literature study with input from external experts and own experience, the outlines for a roadmap on these topic are sketched. Lifetime extension and re-powering are end-of-life options that consider continuation of operation with original components and replacement components respectively. The study shows that lifetime extension requires monitoring of all components of the wind farm except the electrical infrastructure, which typically shows less wear and has a life up to 40 years. All other components of a wind farm are typically designed for 20 years of operation. To be able to decide on continuing operation, the owner requires infor-mation on the state of the farm, the permitting and safety conditions. Moreover, the business case for lifetime extension currently relies heavily on an extended subsidy programme. Existing wind farms are not designed for lifetime extension and are insuffi-ciently monitored. Re-powering typically considers installing state-of-the-art turbines on existing founda-tions and electrical infrastructure. Again the technical trade-off is based on the actual state of the components at the commercial end-of-life of the farm. This requires con-tinuous monitoring of at least the foundations and electrical infrastructure in the farm. Operational wind farms are currently insufficiently monitored and not designed for re-powering, especially when considering increasing the capacity of the farms in the “sec-ond life”. Such intentional over-dimensioning will only take place when the residual value of the farm after 15-20 years is considered high enough to justify continued oper-ation for another 15-20 years. The incentive for farm owners to design for re-powering, must be formed by a new governance model. Legislation must be in place before 2025 to grant extended permitting and a renewed subsidy scheme. Developing such govern-ance models require instant action, as they will effect operation of wind farms 40 years from now. When lifetime extension and re-powering are not considered viable, or when the wind farm has reached technical end-of-life, the wind farm must be decommissioned. De-commissioning requirements are defined in the contract and may include removal of the electrical infrastructure. Level of re-use or recycling are yet to be defined by the authorities. As the first UK wind farms are being decommissioned, we see the industry is in need for a dedicated decommissioning strategy, as the farms are currently being dismantled in reverse installation order. Special equipment is being developed and innovation within this sector has not yet reached its peak. Being very strong in the in-stallation of wind farms, the Dutch industry can play an important role in the (interna-tional) decommissioning of the wind farms. The opportunities are significant and very relevant. We suggest to prioritize research into this field of wind energy. The road map provided, shows that developments both on a technical level and on a governance level, must be finalized and implemented by 2025. The 9 years give us the possibility to prepare for making choices for the currently operational wind farms (which requires monitoring) and the wind farms that are to be designed after the Energy Agreement. These developments start with a stakeholder dialogue with all nationally parties involved. "

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