RecycleWind – Conception and application simulation of a self-learning recycling network for the resource-saving control of material flows for high-quality and especially long-lasting products using the example of wind turbines.

Project duration: August 2020 – January 2022

Brief description

With the approach of RecycleWind and the foundations created there for a resilient and self-learning recycling network, a completely new path is being embarked on terms of manufacturer responsibility in waste legislation, in order to ensure high-quality recycling also for long-lasting products with useful lives of 20 and more years, such as wind turbines.

The focus of the project is on research and development of scientifically proven methods of self-control in material flow systems, the simulation of possible applications and concept development of suitable services for this new approach of such a network.

Project duration RecycleWind 1.0: 23.02.2018 – 31.10.2019

Project duration RecycleWind 2.0: 01.08.2020 – 31.01.2022 (internal continuation as project RecycleWind 3.0)


Activities & aims

Wind turbines are high-quality complex products made from a variety of materials. A significant market has only existed for about two decades. The first plants today reach the end of their product life cycle or will be replaced by more powerful types in the course of repowering. There are currently several options available for further use respectively disposal of these End-of-life plants (Eol-WEA):

a) reuse as “second-life” equipment,
b) use of components as spare parts,
c) material or raw materials or
d) disposal.

The recyclability has not been considered at construction of old systems and is playing only a subordinate role in new systems to date. The functionality and the achievable power output are the main drivers. In addition, a disposal is usually only scheduled for 20 to 30 years after the installation of the facilities.

The existing regulatory instruments in the waste management sector, such as government regulations with fixed quotas or voluntary commitments by the industry involved, have generally failed to prove themselves in the sense of an increasing recycling rate for high-quality recycling with closed cycles. The new German Packaging Act therefore, for the first time, attempted to downgrade poorly recyclable packaging by means of a malus system compared to recyclable packaging, thereby creating incentives for “good” products.

In addition, product responsibility regulations are becoming increasingly focussed. The revised European Waste Framework Directive introduces an “extended producer responsibility regime” that obliges producers of products to assume financial responsibility or financial and organisational responsibility for management, including separate collection and sorting and treatment processes, during the waste phase of the product lifecycle. This obligation may also cover organisational responsibility and responsibility for preventing waste, as well as contributing to the reusability and recyclability of products. Producers of products may fulfil the obligations under the extended producer responsibility regime individually or collectively. Legal regulations have been put in place for old cars, batteries and electrical appliances as well as for packaging.

So far, there are no specific requirements with regard to disposal for the product system “wind energy plant” apart from the generally applicable requirements of the circular economy law [KrWG 2012]. In particular, the provisions of §23 (Product Responsibility) have not been implemented so far. The Federal Council’s approaches to the future possibility of authorising mandatory “Environmental Product Declarations (EPD)” were not adopted by the responsible Federal Ministry as part of the current amendment to the Circular Economy Act (as of Sept.2020).

Recycling of steel and concrete as main components of a wind turbine is already more or less well-established, the situation for the rotor blades, mainly made of fibre composite plastics, was different at the beginning of the project in 2018.

In the years after 2020, with the phasing out of EEG funding for the plants of the first generation, the material masses from dismantled or repowered plants from the onshore sector will increase significantly. According to forecasts by [Albers et al. 2016] using the example of GRP from rotor blades, from the year 2020, approximately 10,000 Mg/a to approx. a maximum of 22,000 Mg/a of rotor blades can be expected; for the period up to 2030 in total approx. 190,000 Mg. The German WindEnergie Association (BWE) in 2018 assumed a possible accumulation of disused rotor blades by 2025 of approx. 140,000 Mg [BWE 2018].

At the same time, it was and can be seen that the masses will fluctuate strongly over the first few years after EEG funding expires depending on the expansion and dismantling scenarios (including second-life) and repowering concepts.

In this aforementioned context, the joint project RecycleWind 1.0 was launched in February 2018 via Bremer Aufbaubank GmbH with EFRE funds and funds from the Applied Environmental Research (AUF) programme of the Bremen Senator for Environment, Construction and Transport. The aim was to develop criteria for the creation of a self-learning and resilient recycling network for wind turbines.

For the development of the RecycleWind concept as a self-learning and resilient recycling network, the focus was placed on the rotor blades which were still difficult to recycle or dispose of. In this context, existing barriers should be clearly visible on the basis of the current structures of utilisation technologies and stakeholders, and solutions should be developed from them.

On the basis of recorded basic data (database wind turbines and process descriptions regarding deconstruction, dismantling and recycling of rotor blades) and visualisation by material flow models a self-organisation supported by the relevant actors should generate appropriately adapted recycling solutions. Instead of rigid recycling quotas by the legislator, this model is intended to ensure high-quality recycling that can react flexibly to changes in external conditions.

For this, the following questions had to be answered at the beginning of the work, which should be regarded as the basis for decision-making:

  1. What are the objectives, tasks and responsibilities of the actors in the process chain?
  2. Which “second-life” products and wastes from which components are produced at what times in which mass streams and qualities at the end of the life cycle?
  3. Which recycling routes with which technologies must be available?
  4. Which markets and applications are available for the reused products and recyclates?
  5. How does an adapted recycling network look like?
  6. Which framework conditions and requirements must be set?
  7. How can be react flexibly to changes in framework conditions without having to abandon overarching efficiency targets?

In Fig. 1, the working levels planned for this at that time are shown. Through a tragic personal event, the agent-based modelling by the University of Bremen could not be realised. The university therefore had to withdraw from the joint project.

Fig. 1: Processing Layers RecycleWind 1.0

The following results have to be recorded from the Recycle Wind 1.0 project with expiry of 31.10.2019:

  1. The process chains are shown for the example rotor blade over the entire life cycle. The business and technical processes that are influencing the material flows ar identified. The responsible actors are characterised and described by their possible options for action (in particular, the disposal of carbon fibre plastics, e.g. the possible formation of WHO fibres in waste treatment, is a problem).
  2. The approximately 28,000 wind turbines onshore available in Germany are recorded in a database (Excel) with their characteristics and material quantities for the rotor blade types installed.
  3. Material flow models along the life cycle of a rotor blade, including analysis of environmental impacts in the form of LCA analyses, are exemplary elaborated.
  4. Initial approaches for standardisation of dismantling processes are the focus of the stakeholders concerned; with the participation of employees from the project RecycleWind 1.0, the DIN Spec 4866 “Sustainable deconstruction, dismantling, recycling and reutilization of wind turbines” was developed (publisched in August 2020 by Beuth-Verlag).
  5. Initial conceptions for a recycling network include the establishment of a quality association RecycleWind. In this quality association the actors along the life cycle of a WEA, i.e. manufacturers, operators and waste management companies together with science and government representatives under the direction of a “neutral body” shall develop standards for the design and specifications for dismantling as well as the reutilisation of individual material flows. To control the material flows, definitions relating to recyclability and recycling quota have been developed and in this context a “secondary stock quota” is newly introduced.
  6. Transparent product declarations for the main components are considered necessary for working in the quality association. The environmental product declaration (EPDs) already established in the field of “Sustainable Building” as an eco-label class III according to DIN ISO 14025 is regarded as a good basis for this. A blueprint for a future EPD-plus was developed for rotor blades. The “plus” stands for a transparent presentation of dismantling instructions and the future assessment of recyclability within the EPD with a distinction in the information on recycling in “high quality recycling” and “other” recycling.

There are more detailed explanations In the section “Previous project results RecycleWind incl. Update“.

Further information on this project, the goals and the possible solutions at that time can be found via link to “RecycleWind 1.0“.

Within this joint research project “RecycleWind 2.0”, a powerful flexible reutilisation network as a pilot application for durable products is to be developed in a previously unregulated but currently important “green” product market for wind turbines based on the state of the art and the previous work from the previous project RecycleWind 1.0. Figure 2 shows the working approach based on the previous project. Due to the complexity of the network, the¬ project will continue to focus on the most problematic components of the rotor blades made of GRP or CFRP composite materials. However, it should be designed in such a way that an extension to the entire wind turbine is possible and the results could be transfered to other product systems (example: Shipbuilding and aircraft construction).

Fig. 2: Procedure and results of the RecycleWind 2.0 project with interfaces to the previous project RecycleWind 1.0

Since essential framework conditions, such as market developments, can change in the course of product life, this network cannot work with rigid specifications. It must be able to react to the changes of the requirements robust, adaptable, innovative and capable of improvisation, i.e. self-learning and resilient, and be able to meet the legal framework requirements. The main idea here is that, based on the residual value of a product at the end of its product life and the new value after passing the recycling system, only a certain efforts for dismantling and recycling (technologies, organisation) can be made. Nevertheless, the requirements regarding efficiency parameters (material, energy, climate protection, costs, etc.) must be met. Depending on the market situation, the recycling strategies and the actual recycling routes will therefore have to be adapted without leaving the legal requirements. In order to work, the specifications for this system must also be -flexible in a guiding framework. The guiding framework results substantially from the policy guidelines (energy, environmental policy, general framework such as sustainability).

The main methodological elements are:

  1. Comprehensive product declarations by means of adapted EPDs regarding recyclability
  2. Material flow models for the description and evaluation of process chains and material flows throughout the life cycle on the basis of a central product database
  3. Agent-based modelling to map options for action and their impact, taking into account the interests of stakeholders in relation to the target formulation of the reutilization network
  4. Approaches for establishing an “association of quality RecycleWind” with the participation of all relevant actors to ensure the highest possible recycling for wind turbines with the help of monitoring models in comparison to the framework conditions including suitable control elements

For the first time, the project will transfer design elements of resilient socio-technical systems to the wind energy reutilization system. Resilience in this context means that the recovery system must be able to adapt flexibly to changing conditions. Technical-organizational elements such as buffers, memory, modularity, redundancies and an intelligent networking of supply and demand are generally considered for this purpose [Gößling-Reisemann et al.2016].

In order to verify the performance of the resilient design elements, they will be transferred to a dynamic model of the wind energy reutilization system. Based on the status quo of reutilization practice, innovative elements are then introduced into the system in order to verify their impact on the system’s ability to deal with uncertainty and fluctuations. As modelling tools particularly “agent-based models (ABM)” are suitable. On the one hand disseminate dynamics of technical and organisational innovations and on the other hand their impact on material flows can be mapped with these tools. Since an ABM is based on the mapping of stakeholder actions that typically work together in networks, workshops and/or interviews with all relevant actors in the wind energy reutilization network are conducted to specify the model. The actors provide knowledge about their decision-making practices and thus help to map the impact of technical or organizational innovations in a fluctuating environment in a realistic way.

Fig. 3: Schematic definition of an agent-based model from [Arnaud Gridnard 2017], Agent-Based Visualisation, with customised layout design (

As main results fo the RecycleWind 2.0 project are expected:

  1. Creation of an EPD format using the example of rotor blades that takes into account the recyclability of the products
  2. Updating data collection on rotor blades from potential EoL-WEA (Excel) and creating a concept for a central modular expandable database for the other main components
  3. Definition of recyclability and integration into material flow models/life-cycle analyses
  4. Agent-based (modularly expandable by other main components) modelling using the example of rotor blade
  5. Adaptation of the rough structure elaborated in the project RecycleWind 1.0 – resilient and self-learning” for the planned recycling network in the context of the results obtained in this project, in particular with regard to the use of the service modules central database, material flow model and ABM

Previous project results RecycleWind incl. update, Status 08/2023

In addition to the development of sufficient basic data, such as the inclusion of all onshore wind turbines in a higher-level database and the inclusion of processes between all relevant actors for the dismantling and reutilisation of rotor bladestwo fundamental aspects have been identified for the future establishment of an effective recycling network::

  1. Due to the frequent lack of data on the material composition of the main components in already completed decommissioning projects of onshore wind turbines, the establishment of a standardised product declaration is considered as necessary. The use of so-called Environment Product Declarations (EPDs) is proposed, which have already been introduced as eco-labels in Europe. They are currently mainly used in the construction sector.
  2. In addition to the establishment of EPDs, the establishment of a quality association “RecycleWind” was also proposed in order to ensure a high-quality recycling of wind turbines within the framework of this self-organisation.

Defined key figures or terms relating to recycling and recovery are necessary for control in a recycling network. In the context of the RecycleWind project, corresponding definitions of terms have been defined in the context of a future recycling network to serve as control variables in the context of the RecycleWind project, based on long-term discussions on recycling quotas and their definitions and recent definitions in European and German waste legislation.


In order to estimate the masses and expected source streams, an Excel database “RecycleWind” with all wind turbines installed until spring 2018 was created in RecycleWind on the basis of the installed systems onshore in Germany.

The database contains all data from the wind turbines on land of the Federal Network Agency’s register of installations (status: Spring 2018) as well as the data sets of the installations that were installed until 08.2014 from the registers of network operators (TransnetBW GmbH, TenneT TSO GmbH, Amprion GmbH and 50hertz Transmission GmbH).

The system type with the respective electrical outputs and rotor diameters (if available) as well as information on location (postal code) and allocation to the federal states were recorded, so that analyses can be presented separately for each Land.  Each wind turbine was assigned one of the four wind zones via the given ZIP. For all systems in the database which do not have information on the rotor diameter, the rotor diameter had to be estimated using a trend function. For this purpose, the trend from the real rotor diameters was determined for each wind zone in the register sheet “Windzone Rotor Diameter”.

This database has been adapted in RecycleWind 2.0 based on the market master data register released since April 2019 and will be continuosly updated (current status 12/31/2022).

In cooperation with the rotor blade manufacturer Euros GmbH, based in Berlin; today, TPI Composites, and literature searches are used in the database to assign rotor blades with carbon belts “CFK” on the basis of the plant types of the WEAs. All other installations were classified as “CSFs”. Also, initial estimates of the material composition for CFRP and GRP rotor blades were made and trend statements on rotor blade masses depending on the rotor diameter were made. These approaches are condensed with continuous input data and then taken into account in the updates of the database.

Table 1 shows the percentage material composition currently assumed for “CFRP” and “GRP” rotor blades WEA type onshore (status 09/2022).

Tab. 1: Estimation of the percentage material composition for “CFRP” and “CSF”—Rotor blades, staggered according to power classes in MW el

In addition to the prognosis of total masses (see Figures 4a and 4b), this procedure enables a material-specific evaluation of end-of-life rotor blades. The different material compositions in the GFRP or CFRP blades are taken into account in relation to the individual power classes of the WEAs considered.

Fig.4a: Estimation of the mass volume of end-of-life (EoL) rotor blades of the GFRP type for onshore WEA in Germany based on installed turbines, status: 12/31/2022

Abb.4b: Estimation of the mass volume of end-of-life (EoL) rotor blades of the CFRP type for onshore WEA in Germany based on installed turbines, status: 12/31/2022

In addition to the total masses of EOL rotor sheets, regional evaluations are also possible via the allocation of WEAs to the federal state and postal code.

Offshore WEA

The database described above was also created analogously for offshore wind turbines on the basis of the data in the market master data register (as at 31.12.2021). In addition to the allocation to hub height, plant type and foundation structure as well as the allocation of CFRP or GRP rotor blades and resulting rotor blade masses, masses adapted to the respective performance classes for the other main components hub, gondola, tower, TP and foundation are also shown as trend data.

This allows first trend analyses of EoL masses to be carried out in the case of offshore wind turbines to be dismantled. This information is particularly important in the planning of necessary technical facilities, aggregates and intermediate storage capacities for the reception and initial treatment of the main decommissioned components at a port site.

Figure 5 shows the estimated EoL masses for offshore wind farms approved in Germany up to 2041.

Fig. 5: Estimation of EoL masses from WEA Offshore Germany; Acceptance 20 years of operation, Date: 31.12.2021

Especially in connection with long-lasting products, such as the rotor blades of wind turbines, information on installed materials and constructions is enormously important for later recycling efforts, because it may no longer be possible to rely on the manufacturers themselves.

In today’s expert discussion on the transformation towards the circular economy, sufficient product information is regarded as a fundamental key element. Demands for so-called product passports are increasingly resonant in waste management.

One way to provide environmentally relevant product information is the EPD.

The abbreviation EPD derives from the English name Environmental Product Declaration and is usually translated in German with environmental product declaration. An EPD is a Type III Ecolabel (according to ISO 14025), i.e. a comprehensive and externally verified description of environmental performance without rating.

An EPD is a document that depicts the environmental properties of a given product in the form of neutral and objective data. This data covers, as far as possible, all the effects that the product can have on its environment. Ideally, the entire life cycle of the product is taken into account, including end-of-life.

EPDs are based on life cycle assessments according to ISO 14040 and ISO 14044, in which the environmental impacts of a given product are summed up and analysed over its life cycle. DIN EN 15804 describes the standard for the creation of EPDs of construction products. A particularly important feature of life cycle assessments is that they not only provide individual key figures or assessments, but can also map a variety of different environmental influences individually. For example, in addition to greenhouse gas emissions, DIN EN 15804 also takes into account other influences such as acid rain, the formation of smog, the consumption of fossil resources and water or the proportion of recycling.

Manufacturers of products or co-balancers commissioned by them have so far been confronted with the task of collecting and evaluating data for the production phase and the use phase (EPD modules A and B), as well as data for EPD modules C (construction, re-use, recovery, disposal) and D (recycling potential). As a general rule, there is much less data available for these processes. These are therefore usually mapped with generic data relating to waste disposal and recovery operations. Since there are no narrow guidelines for the selection of end-of-life scenarios, assumptions made for this may vary greatly, which makes comparability very difficult. These structural deficits have also been identified in the UBA opinion on the further development of EPDs in the construction sector (Texts 128/2021 and Texts 129/2021) and recommendations for adapting them.

In the RecycleWind 1.0 and 2.0 project, the existing approaches of EPDs from the construction sector were developed in parallel. In addition to information on the material composition, statements have also been made about their recyclability. This requires information on the installation location of relevant materials, including in the form of a design sketch and information on their dismantling possibilities. In addition, standardisation is required for the assessment of the recyclability of materials in the End of Life.

In the RecycleWind project, recommendations have therefore been drawn up on the basis of the existing standards for the content of such a product declaration supporting the recycling and closed-loop concept using the example “rotor blade”. The expanded “EPD rotor blade 2.0” with integrated recycling assessments can thus serve in the future as a basic document for recycling for the main components WEA and includes:

  • Information from the manufacturer about a product and its components, for dismantling, so that waste disposal and recycling companies can facilitate the execution of optimised end-of-life workflows
  • a statement/assessment on recyclability, including the presence of circulatory systems
  • an evaluation of the product using LCA analyses (including carbon footprint) and presentation of credits through material flows in recycling and/or recovery processes

The evaluation of a whole wind turbine requires several EPDs, each for the main components.

In the Download & Publications section you will find the latest version of the EPD Rotor Blade 2.0.

Specifications for the assessment of recycling and recyclability using the example of rotor blades

The classical EPD according to EN 15804 provides the following indicators for waste and output flows:

  • landfilled hazardous waste
  • landfilled non-hazardous waste
  • radioactive waste disposed of
  • Components for recycling
  • Materials for recycling
  • Substances for energy recovery
  • Exported energy (electric)
  • Exported energy (thermal)

This is not sufficient to assess a product in terms of recyclability. The following chapters describe the approaches developed in the RecycleWind project.


When considering the recyclability of a product, apart from the assessment of recycling rates for the total product, here the rotor blade, separate material-specific considerations for the relevant material are considered. Use the most relevant materials and substances for the protection of resources and climate protection. This concerns the “critical raw materials” according to the EU definition and the particularly CO2or energy-intensive substances, insofar as the latter are used in quantitatively relevant mass fractions. In the case of ‘critical raw materials’, separate consideration is carried out independently of the w/w/% of these substances.

In addition to these two separate material-specific considerations on recycling, a presentation is also carried out for possible hazardous substances incorporated in EoL material and their recycling or elimination possibilities in the decommissioning and disposal process to strengthen the recyclability and prevent ubiquitous distribution.

To assess recyclability, used (raw) materials, semi-finished products and products are listed with regard to their classification as “critical raw materials” and with their GWP values or their data on primary energy demand (PED) (see Table 2).

In the allocation as a critical raw material, attention must also be paid to indirect allocation, e.g. aluminium wg. Classification of bauxite as a critical raw material or in the case of semi-finished products, products also on their compositions and in proportion of critical raw materials, e.g. E-glass fibre wg. 5-10 % of boron oxide (i.e. borate classified as a critical raw material). However, not all electric glasses contain boron, the more important it is to be declared by the manufacturers in the context of the EPD.

In the case of ‘critical raw materials’, it is proposed that this separate consideration be carried out independently of the w/w/% of these substances. This approach also applies to installed hazardous substances, insofar as they are still contained in the materials used in their original state/effect mechanisms.

In the case of energy-intensive substances, it is proposed that a PED value higher than twice the calorific value for crude oil of 42 MJ/kg be considered separately. 2 times the calorific value for crude oil, the aim is to take into account energy-intensive finishing into plastics, which goes beyond the energy content of the substance, and only then to be drawn up as a highly energy-intensive substance in relation to the recyclability of a product. In order to estimate the quantitative relevance of the latter materials for a real product, the PED values are multiplied by the percentages of weight in the product. If this sum, which describes the PED proportion in the finished product, exceeds a value of 20% of the sum of all specific PED values of the product, this is classified as proportionally relevant and an additional separate analysis is carried out for these energy-intensive substances.

Tab. 2 summarizes such an evaluation or allocation using the example of the CF-type rotor blade from the EPD Rotor blade 2.0.

Tab. 2: Characteristic data on GWP/PED of materials used Rotor blade CF type from the EPD Rotor blade 2.0

*) = COMMUNICATION FROM THE EUROPEAN COMMISSION: EU resilience to critical raw materials: Set a path towards greater safety and sustainability; Brussels 03/09/2020
**) = sum of PED MJ/kg * weight share of built-in material;
red = relevant energy-intensive (starting) materials or energy-intensive product components

As a result of the evaluation of the materials to be given special consideration, the following materials are most important for the rotor blade type shown here

  • with regard to the classification as “energy-intensive materials”, the carbon fibers and the epoxy resin as well as
  • with regard to the classification as “critical raw materials” the carbon fibers, aluminum and glass fibers

then to be considered in detail.

Hazardous substances that are still relevant for action are not present in EoL materials.

With regard to the assessment of recyclability, for the climate- and resource-relevant materials, it will be examined whether for these incorporated substances:

a) disassembly instructions for separation and
b) existing recycling processes, pathways are in place and
c) assess their effectiveness in terms of real circulation or cascading use.

In the case of ‘dangerous substances’, it is examined whether for these substances or materials contaminated with them:

  • Disassembly instructions or instructions for separating the existing dangerous   Substances are present and/or
  • whether these are efficiently discarded in subsequent recycling processes it’s possible.

Circulatory capacity

In addition to recyclability, the associated ability to support circularity is described in a circular economy. For this purpose, the following definition of circulatory capacity is used:

circular output streams; from recycling processes that

a) Generate recycled qualities that can replace material-like new products, i.e. as “substitute secondary raw material or recyclate” are included in the new product (e.g. aluminium or rCF in textile fabrics) or completely replace them (forming thermoplastics) and/or
b) Generate raw materials (components of pyrolysis oils or gases) which are used for production of material-like new products can be reused again.

This is equivalent to output streams or recyclates, which do not replace material-like new products but are used for production in other products, and at the end of which they can be recovered again as recyclates of the raw material (usability of the original properties) (including the production of public furniture from GRP segments, the use of CFRP casts into new semi-finished products or rCF from rotor blades in new textile fabrics), or raw materials used for other products (non-material new products) and which can also be re-generated from them.

For the purposes of this definition, ground fibre composites, glass or carbon fibres with length of e.g. < 0.5 to 1 mm and their subsequent use in new plastic products shall be considered as non-circular for the purposes of this definition.

The output indicators defined in the existing DIN EN 15804 + A2 are used to support an evaluation of recyclability and circularity, of materials incorporated in the product

  • „Material for Recycling (MFR)“: material recycling (in the case of rotor blade: Glass fibres as material materials for new production cement, MPC plates, paving stones; Use of rCF*) in injection molding/nonwoven, metal recycling),
  • „Material for Energy Recovery (MER)“: energy recovery as a qualified fuel with defined quality requirements (in the case of rotor blade: Plastic content (epoxy matrix, hard foam), balsa wood in cement plant)

are complemented or differentiated by the following indicators:

  • Material for Circularity (MFC) = Material is kept in circulation (in case of rotor blade: GRP/sandwich matrix as (new) furniture, new fabric of rCF, metals)
  • Material for energetic utilisation (MEU) = energy recovery as a non-qualified fuel without specified quality requirements (in the case of rotor blade: Combustion of balsa wood in waste wood power plants at recycling path paving stones)

The recommendations on the content extension of the previously mandatory information in an EPD on recycling and disposal, in particular the higher level of detail in the section Disassembly and the new approaches to describing recycling and circularity, can be considered in view of the shortcomings mentioned in the above-mentioned UBA opinions on EPD’s from the construction sector (Texts 128/2020 and Texts 129/2020). Dismantling, disposal and recycling potential are considered effective.

Similarly, these implementations of an extended EPD or their contents can also serve as a good example of the recycling passports currently under discussion in politics (see, inter alia, the EU Commission proposal for the amendment to the Eco-Design Directive of March 2022), which also reflect an assessment of the recyclability of rotor blades in accordance with the amendment to the German wind on the lake law.

LCA evaluation in the EPD

In the LCA evaluation underlying the EPD, dismantling and recycling processes shall be considered in detail and corresponding credits for use as secondary materials shall also be included. For this purpose, process data sheets with the mass and energy flows must be available for all recycling steps or processes, which are largely based on real data or estimates based on it. These evaluations for EoL treatment must include the entire recycling chain, from dismantling to the various processing processes to the possible final cleaning step in the use of the secondary raw material in new production.

Our work has enabled data to be determined in detail for the dismantling of onshore wind turbines, including the further processing of material flows. These are presented in process-related data sheets. The following data sheets are currently available:Durch unsere Arbeiten konnten für den Bereich des Rückbaus von onshore-Windenergieanlagen inkl. der weiteren Aufbereitung der Stoffströme hierfür nun Daten im Detail ermittelt werden. Diese werden prozessbezogen in Datenblätter dargestellt. Es liegen derzeit folgende Datenblätter vor:

  • Dismantling WEA-onshore
  • Cement path GRP
  • MPC plate path GRP
  • Paved stone path GRP
  • Pyrolysis path CFK

The data sheet Disassembly WEA also includes the preparation of the steel components up to the steel plant quality, i.e. shredding to dimensions of 150 cm x 50 cm.

After disassembly of the foundations and any concrete tower segments for further processing into recycled building materials or recycled concrete concrete, detailed analyses are already available for concrete from the decommissioning of WEA’s. Mass and energy flows that can be used [Lit. 9].

The disposal routes for medium-voltage cables, batteries and e-waste including transformers, as well as for generators for which established recycling routes are available and the basic characteristics for these respective treatment and recovery paths are described in a variety of ways in the literature were not considered.

A separate consideration is required for the disassembly and recycling of permanently installed magnets in the transmissions and partly in the towers. An established disassembly method for the recovery of permanent magnets does not yet exist, especially for the permanent magnets, which are sometimes very heavy in the case of the WEAs, with their strong magnetic forces. There is also a high need for development and research for the recycling of these components (currently a research project of the German Federal Environment Foundation is taking place: WindLoop — Efficient return of rare earth and non-iron metals from wind turbines into the material cycle; DBU-AZ: 37114/01; Period 16.4.2021-16.4.2023). Therefore, there are no data for these materials at this time. Dismantling, dismantling, reprocessing and recycling available that would allow an assessment.

The data collected in the developed process data sheets form the basis for material flow modelling and for life cycle analyses. Only processes that are available on the market according to the state of the art are taken into account. For example, for the glass fibre reinforced plastics (GRP path), the recycling and recycling routes shown in Figure 6 are considered and assessed in terms of the CO2 footprint or the Global Warming Potential (GWP) (see as an example LCA comparison for some GRP recycling processes in Figure 7).

Fig. 6: Forecast material stream recycling, recycling of GRP materials from EoL rotor blades for the year 2036 based on state of the art and market in 2021

With our approach of detailing process data sheets and substitution effects, these environmental aspects could be visualised very well based on the global warming potential by means of the LCA evaluation. In addition, the results of these life cycle analyses provide important information on the evaluation or control of recycling towards circularity. It always requires an overall consideration of energy expenditure and achievable circularity. The more energy-intensive the steps towards the recovery of individual substances in the sense of circularity are, the more crucial it is to accompany this path critically with regard to a real implementation.

Fig. 7: Global warming potential comparison for the recycling paths of cement path and MPC path of GRP materials from the dismantling of rotor blades; including credits by substitution of sand, clay and limestone as well as primary energy at the cement plant and substitution of limestone and polypropylene in MPC as well as limestone and polyester in the paving stone

At the beginning of the first project in 2017/18 and as an interim result of the work in RecycleWind 1.0, the focus was on the following points: 

  • Lack of communication between actors, no joint action strategies
  • The information situation on material composition and mass flows was/is not sufficient
    • Intellectual Property Rights versus Transparency
  • Unsatisfactory legal framework, no responsibility of the manufacturer for the design of recyclable rotor blades or product declarations
  • no uniform requirements of authorities for dismantling
  • Economic interests versus life cycle thinking and acting
    • Market potential for recycled glass fibres is low
    • Recycling and disposal of carbon fibres is not yet established

Based on these interim results, an approach in RecycleWind was taken to build the recycling network as a quality community.

Model approach of a quality association “RecycleWind”

The basic element of such a quality group, which already exists in the field of waste management for (mineral) recycling materials, compost or for secondary fuels, but is also known for products such as the RAL quality-resistant mineral wool, is the establishment of a quality committee which ensures compliance with the requirements for quality assurance.

All key stakeholder groups should be represented in the Quality Committee by appropriate members; in addition, representatives of licensing authorities and R & D. Since the players can also act as competitors among themselves on the market, the organisation and coordination as well as the moderation of the quality committee can be managed by a “neutral body”, such as an institute of the Bremen University of Applied Sciences.

The Quality Committee awards quality labels to member companies that comply with the established standards. This must be demonstrated by successfully participating in defined certifications/reviews.

The work of such a quality group is based on sufficient product declarations from manufacturers; in the case of WEAs, the main components must be considered separately. The developed EPD-plus or the data required therein should be considered as standard for members of the Quality Association, unless they will be required by the legislator in the future, in particular for long-lived products.

Through an ongoing update of the evaluations, the Quality Community is thus also creating a permanent reassessment of the “old” EPDs. This recurring (re)assessment alone meets the recycling of durable products and thus also producer responsibility.

In addition, an overview of the overall stock of all wind turbines and their characteristics is of great importance for the work in the quality community. Only through this can material flows of the current and future stock be mapped or projected and thus necessary processing and recovery capacities can be estimated or identified. In the event of a lack of capacity, appropriate solutions should be discussed within the scope of extended producer responsibility.

Several consultations were held on existing associations from the wind energy industry and manufacturers of wind turbines. For example, VDMA, BWO, Vestas, Siemens-Gamesa, WindEurope, Deutsche WindGuard, RDR-Wind e.V: informs about our presentation and determines its point of view.

Recycling network / Quality Association 3/2022

In this context, it should be noted that today the picture is different compared to the starting situation:

  • DIN SPEC 4866 for dismantling, dismantling, recycling and recycling has been published since 8/2020, currently in the evaluation phase
  • Legal requirements for the dismantling of approval authorities are largely orderly and two reports commissioned by the UBA are expected to make further recommendations by the end of 2022; among other things
    • for work and immission protection when cutting and shredding the FVK with glass and carbon fibers
    • to deal with pile foundations during dismantling onshore WEA
    • Recommendations on organisational responsibility issues related to dismantling, recycling
  • Bringing relevant aspects of WindEurope to dismantle and recycling [Lit 13] into the European legal framework at the International Electrotechnical Commission TC88 for wind turbines to obtain an amendment to the IEC 61400-28 CD “Technical Specification Wind energy generation systems — ThroughLife management and life extension of wind power assets”. The amendment aims to add content for the end of life in the regulation.
  • The business runs for the relevant manufacturers and operators throughout Europe, i.e. a solution for a recycling network must be established throughout Europe.
  • Due to the high price level so far, the recycling of fibre composites from the claddings and the rotor blades is more and more players across Europe who offer solutions. Rotor blades from Germany and Austria are transported as 5 to 12 m long segments to Portugal. Some of them are recycling approaches with currently only small capacities of 1,500-5.000 mg/a.

In addition, the most important manufacturers and operators in their respective company-owned sustainability policy or corporate strategy have agreed on climate-neutral production and circular material flow models (see also comments on AP 3).

To this end, the leading manufacturers GE, Vestas, and Siemens-Gamesa have come together in joint projects; including DecomBlade; Start Jan. 2021 (with a focus on new recycling approaches) and ZEBRA (Zero Waste Blade ReseArch); Start Sept. 2020) (with focus. new designs of rotor blades).

This broadly uniform target formulation in the sector therefore does not focus on different waste strategies with different market participants, but rather on providing evidence of the self-selected achievement of targets and their transparent communication to the public. For this purpose, a cooperation with representatives of all the value chains involved in a European approach to a recycling network, usefully within the WindEurope industry association, is appropriate. As a result, the target achievement levels are to be published here. In addition, this platform should be used to forecast dismantling masses in advance on the basis of specific planning by operators in order to demonstrate the necessary capacity of necessary facilities and machinery (including heavy-duty cranes for dismantling onshore, transport units offshore, initial treatment capacities at relevant port sites).

A deepening of the discussion is to be conducted at the level of the associations VDMA, WindEurope, BWO, BWE, RDR-Wind regarding a European approach to such a network. The results of the previous work in the RecycleWind project should, if possible, be included in the current activities at “Windeurope”:

  • WindEurope Decommissioning and Dismantling with the aim of bringing dismantling and recycling relevant aspects into the European legal framework at the International Electrotechnical Commission TC88 for wind turbines (see above).
  • Provide an overview of existing treatment capacities for EoL-WEAs in Europe

to be brought in.

The tools developed here in this project RecycleWind

  • the extended environmental product declaration,
  • the WEA Database
  • the process data sheets
  • Substance flow analyses incl. LCA evaluations

provide a good basis for working in such a recycling network and could be provided as services here.

In contrast to the previous approach of setting up a quality association under German law as a complete organisation (and the associated possible establishment of a service as a “neutral” operator), a focus on the aforementioned services appears to be useful among the given reactions from the market or relevant actors. A recycling network for the recycling of wind turbines should be established throughout Europe, if possible in an existing industry association such as WindEurope.

Project partners

Logo IEKrW

Institut für Energie und Kreislaufwirtschaft an der Hochschule Bremen GmbH, Germany
(Institute for Energy, Recycling and Environmental Protection at Bremen University of Applied Sciences)

The Institute for Energy, Recycling and Environmental Protection at Bremen University of Applied Sciences (IEKrW) was founded in 2000 and is an example of public-private partnership in the field of applied research and development. As an SME, it serves as a transfer point between science and business.

Prof. Dr. rer.nat. Martin Wittmaier
Neustadtswall 30
28199 Bremen
Phone: +49 (0) 421 5905-2326
Fax: +49 (0) 421 5905-2380

Dr. Detlef Spuziak-Salzenberg
Neustadtswall 30
28199 Bremen
Phone: +49 (0) 421 5905-3566
Fax: +49 (0) 421 5905-2380

Universität Bremen, Germany

The department Resilient Energy Systems at the University of Bremen is particularly concerned with the resilient design of energy systems, taking technical, social and economic aspects into account. In terms of method, modeling and simulation, vulnerability and risk analysis, methods of social science empiricism and stakeholder-based assessment approaches are used. In addition, methods of classic technology assessment (including life cycle assessment, risk assessment, toxicology, cost / benefit analysis, scenario technology) are used, which are further developed in the respective research framework, right up to the concept-oriented technology design. The resilience approach of design and development of technologies is understood as a bionic approach, in the sense of “learning from nature”.

Dr. rer. nat Torben Stührmann
Resilient Energy Systems
Enrique-Schmidt-Straße 7
28359 Bremen
Phone: +49 (0) 421 218-64896

brands & values GmbH, Germany

brands & values GmbH is a management consultancy specialized in sustainablility consulting. The main focus is on ecological sustainability. The business areas can be divided into the following areas:

  • Life cycle assessment & life cycle analysisLebenszyklusanalyse
  • Environmental management
  • Sustainability strategy
  • Sustainability communication & reporting
  • Sustainability software

Dipl.-Ing Tobias Brinkmann M.Sc
Lukas Metzger M.Sc
Altenwall 14
28195 Bremen
Phone: +49 (0) 421 709084-33

Cooperating companies

TPI Composites Germany GmbH, Germany

TPI Composites Germany GmbH is part of TPI Composites, Inc. (TPI). We are a leading manufacturer of rotor blades for wind turbines and in 2019 we were responsible for around 18% of all MW-based onshore rotor blades sold worldwide. With over 1.4 billion US dollars in sales and more than 9,500 rotor blades sold, we have reached a new high this year. We enable many of the industry’s leading wind turbine original equipment manufacturers (OEMs) who have relied on in-house manufacturing to outsource the manufacture of part of their rotor blades. Our advanced manufacturing facilities are strategically located around the world to cost effectively serve the growing global wind market.

TPI Composites Germany GmbH
Falkenberger Strasse 146 A/B
13088 Berlin

Carbon-Werke Weißgerber GmbH & Co. KG, Germany

Carbon fibers (carbon fibers) in the form of carbon rovings, carbon tapes, carbon braided hoses, carbon fabrics or carbon prepregs have been used at the Carbon-Werke in Wallerstein for technologically demanding applications for more than 35 years.

These are used in the fields of aerospace / vehicle construction / motor sports / medical technology / mechanical and plant engineering / sporting goods / model making, etc., where conventional materials reach their technological limits. This takes the form of carbon rods, carbon tubes, carbon plates (unidirectional, highly rigid, high-gloss or as a sandwich) in dimensions of up to 6 m in length. The existing machine park also allows individual, tailor-made, high-precision component production, either as a single piece or in series production.

On the basis of research and development together with universities, colleges and institutes, industry-related special applications have been brought to series maturity, which have led to breakthrough innovations in astronomy, laser technology and computer chip production.

All materials and processes are based on the requirements of a sustainable circular economy and also take into account the reuse and further use of the high-quality carbon materials on extremely high technological levels.

Weißgerber GmbH & Co. KG
Albert-Einstein-Str. 2-4
86757 Wallerstein

Downloads & Publications

Previous project "RecycleWind"

Research project to develop a self-learning and resilient recycling network for wind turbines

With the help of the scientific method of agent-based modeling, the effects of long-term strategies on the “rotor blade” product system of wind turbines are to be examined. The aim of the project is to develop specific recycling agreements that are negotiated and implemented jointly by the actors in the product system.

Starting position

Wind turbines are high-quality, complex products made from a variety of materials. The first of the approximately 29,000 systems in Germany are reaching the end of their product life cycle. A sharp increase in the number of plants to be shut down is expected in the coming years. But what happens to these old systems? The wind industry would have to claim to dismantle the “green” energy generation systems as efficiently as possible and to recycle them in a high-quality manner in the sense of the circular economy.

This requirement is currently not being met, and in the future it cannot be assumed that the recycling market alone will be able to dispose of old systems in a way that secures resources. Reasons for this are, for example, the lack of transparency with regard to material flows and problematic material components such as carbon fibers (CFRP).

This is where the research project “RecycleWind recycling network – resilient and self-learning” comes in. This is a joint project of the Bremen University of Applied Sciences, the University of Bremen and the consulting firm brands & values, sustainability consultants in Bremen.

Project goals

In the project, a self-learning recycling network is being developed with the key players at all stages in the life cycle of wind turbines. The aim is for the actors (participating companies or authorities) to jointly define concrete but adaptable recycling agreements for the resource-saving control of material flows.

Solution approach

As prerequisites for the agreements, three methodical elements are worked out in RecycleWind:

  1. the material flow model,
  2. the actor network and
  3. agend-based modeling.

With agent-based modeling, scientifically proven methods of self-control in the material flow system can be researched and the effects of possible actions of the actors can be simulated. Since the essential framework conditions change when wind turbines are operated for around 20 years, the recycling network cannot work with a rigid framework. In contrast to existing control elements in other industries with fixed recycling rates, an adaptable concept of self-control is used. The concept must be able to react to changes in requirements in a robust, adaptable, innovative and improvisational manner, i.e. self-learning and resilient. At the same time, the requirements regarding efficiency parameters (material, energy, climate protection, costs, etc.) must be met. Depending on the market situation and the constellation of actors, the recycling strategies and the recycling routes actually used are fluidly adapted by the actors without missing the efficiency targets that have been set.

Hochschule Bremen (Project management)

Institut für Umwelt- und Biotechnik
Prof. Dr.-Ing Henning Albers
Dr. Frauke Germer
Neustadtswall 30
D-28199 Bremen
Phone: +49 421 5905-2396

Universität Bremen

Resilient Energy Systems
Prof. Dr.-Ing. Johannes Kiefer (komm.)
Dr. rer nat Torben Stührmann
Enrique-Schmidt-Straße 7
D-28359 Bremen
Phone: +49 421 218-64896


brands & values GmbH

Dipl.-Ing. Tobias Brinkmann M.Sc
Altenwall 14
28195 Bremen
Phone: +49 421 709084-33


This Project (FKZ: AUF0009) is funded by the Bremer Aufbau-Bank GmbH with funds from the „Programm zur Förderung angewandter Umweltforschung AUF“ by the Bremen Senator for climate protection, environment, mobility, urban development and residential building and with funds of the European Regional Development Fund (EFRE).