Project ReNEW - Tools for supporting decisions on lifetime extension and repowering of wind turbines

19/07/2024

• Challenge
• Objectives
• Methods
• Partners

In order to ensure that the ambitious targets for deploying wind energy are achieved, a significant number of new wind farms has to be built. On the other hand, existing wind farms reaching the end of their planned life need to be reused efficiently. The ReNEW project develops concepts, models and methods to identify the most sustainable, most economical and technically acceptable end-of-life option for wind farms.

The ReNEW project develops a quantitative framework that enables utility-informed wind farm end-of-life decision-making. A key component of the decision-making process are lifetime analyses of the wind turbine support structures, which are subject to fatigue and corrosion. To this end, models and methods are developed that can be used to (a) analyze the remaining lifetime based on the data and information available from the previous service life and (b) identify optimal inspection and monitoring strategies for the additional lifetime. In addition, global and local repair and strengthening concepts are developed as a basis for the decision-making and technical implementation.

The decision-making tool is (a) designed based on decision-theoretical approaches as a modular system taking into account industry and approval constraints and (b) implemented based on a reference wind farm. It integrates the relevant data, models, analyses, assessments, and actions for analyzing and evaluating the expected revenues, costs and risks associated with each feasible end-of-life option, which are estimated based on stochastic simulations of the additional service life. The influence of the weld fabrication on the fatigue strength of steel structures is analyzed using fracture mechanics and experiments considering local weld repair and strengthening measures. Prototype type component tests are derived and conducted based on the global structural strengthening schemes developed to enable an implementation of repowering options.

Partner
Jörss-Blunck-Ordemann GmbH
RWE Offshore Wind GmbH

Funding
Bundesministerium für Wirtschaft und Klimaschutz (BMWK)
Projektträger Jülich (PtJ)

Wind energy plays a central role in achieving the energy transition and the climate-neutrality objective by 2045. Accordingly, the German government has set out ambitious long-term goals for deploying wind energy. The offshore wind energy capacity is to be expanded from approx. 7.8 GW in 2022 to at least 70 GW in 2045 and the onshore wind energy capacity from approx. 57 GW in 2022 to over 100 GW in 2030. To meet these ambitious goals, efficient end-of-life concepts are currently required for existing wind farms that will reach the end of their planning life soon.

The goal of the ReNEW project is to develop solutions in the form of a modular system that enable (a) the required assessments and upgrades of the wind turbine support structures and (b) a utility-informed wind farm end-of-life decision-making. As a prototype application, the solutions will be implemented for a reference wind farm. In this way, the project contributes towards achieving the ambitious goals for deploying wind energy, as the end-of-life decision-making often disregards the fact that commissioning new wind farms entails a significant portion of structural dismantling and replacement. These works are generally not necessary, and, in addition, they require extra - currently unavailable - capacities of manufactures and contractors. Considering alternative end-of-life options for existing wind farms such as lifetime extension, refurbishment and repowering in the decision-making process ensures that the existing structures are not regarded as scrap metal but as foundations for further utilization of a wind farm site. Quantitative analyses performed to identify the most sustainable, most economical and technically acceptable end-of-life option lead to sustainable and economical solutions.

Data-based lifetime and decision analysis for the reuse of wind turbines

The main goals and objectives of BAM’s sub-project “Data-based lifetime and decision analysis for the reuse of wind turbines” are as follows:

• Development of an integral concept for analyzing and quantifying the utility of technically feasible wind farm end-of-life options.
• Development of a tool to support decisions on wind farm end-of-life options.
• Development of a digital data management that facilitates the data flow from the weld fabrication to the operating phase.
• Development of suitable deterioration models of welded joints subject to fatigue in function of weld fabrication parameters.
• Consider measured and extrapolated loads, load effects and other types of monitoring results in the fatigue life assessment and prediction.
• Development, testing and modelling of suitable mechanical strengthening measures of highly stress fatigue hotspots (e.g., grinding and peening
• Development and prototype testing of concepts for strengthening tubular steel sections.
• Extension of the concepts developed for existing structures to new structures to enable an integrated structural analysis and assessment considering all available data and information such fabrication and monitoring data.
• Demonstration of the economic benefit of the developed concepts.
• Standardization of the developed concepts in the form of a modular system.

Partners

JBO Jörss-Blunck-Ordemann GmbH
RWE Offshore Wind GmbH

Funding

Bundesministerium für Wirtschaft und Klimaschutz (BMWK)
Projektträger Jülich (PtJ)