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










Project approach and project objectives of RecycleWind

Baseline project start 2017/2018

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.





RecycleWind 1.0

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".





RecycleWind 2.0

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: Work packages for RecycleWind 2.0 with their 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

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 blades, two 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.



To estimate the masses and expected material flows, an Excel database “RecycleWind” with all wind turbines installed until spring 2018 was created on the basis of the installed onshore wind energy plants in Germany.

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

The system type with the respective electrical outputs and the rotor diameters (if available) as well as information on location (postal code) and assignment to the federal states were recorded, so that evaluations for each federal state can be presented separately. Each wind turbine was assigned one of the four wind zones via the specified postal code. For all plants in the database, which have no information on the rotor diameter, the rotor diameter had to be estimated using a trend function. For this purpose, in the register sheet “Windzone Rotor Diameter” the trend for each wind zone was determined from the real rotor diameters depending on the power.

In cooperation with the rotor blade manufacturer Euros GmbH, headquartered in Berlin; today TPI Composites, an assignment of rotor blades with carbon belts “CFRP” based on the plant types of the WEAs was carried out. All other plants were assigned “GRP”. In addition, initial estimates of the material composition for CFRP and GRP rotor blades were made and trend statements on rotor blade masses were made depending on the rotor diameter (see Fig. 4).

This procedure enables a material-specific evaluation for the prognosis of resulting end-of-life rotor blades in addition to the total mass.

The first estimates of the material compositions “CFRP” and “GRP” have been and are constantly being supplemented by additional available data of real rotor blade types. Table 1 shows the currently assumed percentage of material composition for “CFRP” and “GRP” rotor blades WEA type onshore.

Fig. 4: Trend function blade masses “GRP” and “CFRK” depending on the rotor diameter

Tab. 1: Estimation of material composition for “CFRP” and “GRP”— Rotor blades, wind turbine types onshore >2MW

The percentages by mass shown in Table 2 are based on rotor blades of the larger plants (>2MW). At the beginning of onshore wind energy about 20 years ago with even smaller plants, the ratio of glass to plastic matrix was still largely 1: 1. In addition, plastic foams alone, i.e. no balsa wood, were used more frequently as sandwich materials; so that significantly higher proportions of plastic foams can be found in the leaves here.


Environmental Product Declaration (EPD)

Especially in connection with durable products, such as the rotor blades of wind turbines, information about built-in materials and constructions is extremely important for future recycling efforts, because under certain circumstances the recourse to manufactures themselves is not possible.

For this reason, the existing approaches of EPDs from the construction sector have been further developed in the RecycleWind project. In addition to information on the material composition, information about their recyclability has to be made here. This requires information about the installation location in the form of a design sketch and information on dismantling options.

Information on possible recycling and recovery processes, in particular for the main components installed, including the purpose of the related reuse shall also be provided.

As part of the project RecycleWind 1.0, a first blueprint for an “EPD rotor blade” based on the previous standardisation, as used in particular for construction products, was created in cooperation with a rotor blade company (see Download “Blueprint EPD Rotor blade”). The focus was set on a good documentation of the material composition, information on the location/principle sketches of materials potentially classified as “critical” for recycling and information on the possibility of dismantling of individual assemblies or main components.

The abbreviation EPD is derived from the English term 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 evaluation.

An EPD is a document in which the environmental properties of a particular product are represented in the form of neutral and objective data. These data cover as far as possible all the effects that the product can have on its environment. In best case, 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 particular product are summed up and analysed over its life cycle. DIN EN 15804 describes the standard for the creation of EPDs of construction products. Mapping a variety of different environmental influences individually is a particularly important feature of life cycle assessments in opposition to providing only individual indicators or assessments. 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 and/or eco-balancers commissioned by them have been faced 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 (reuse, recycling, disposal) and D (recycling potential). For these processes there are usually far less good data available. These are therefore usually mapped with generic data for waste disposal and recovery processes. Since there are no tight specifications for the selection of scenarios at the end of life, assumptions made for this can be very different, which makes comparability very difficult.

In principle, standardisation is required for the evaluation of dismantling and treatment after the end of life of the products and their supply to recycling and/or reutilization processes; that means the potential recyclability.

In the RecycleWind 2.0 project, criteria are to be determined and thus a blueprint for an “EPD-Plus rotor blade” will be created. The expanded “EPD-plus” with integrated recycling assessments will then serve as a basic document on recycling for the main components of wind turbines in the future and includes:

  • Information from the manufacturer about a product and its components, for dismantling, to facilitate the execution of optimised end-of-life workflows for waste disposal and recycling companies
  • A statement/assessment on recyclability, which must also include the presence of circulatory systems
  • An evaluation of the product on the basis of LCA analyses (including carbon footprint) and presentation of credits by material flows in recycling and/or reutilization processes

For the evaluation of a whole wind turbine, several EPDs have to be set up, each for the main components.


Quality Association

The basic element of such a quality association, which already exist in the field of waste management, for example for (mineral) recycling materials, compost or refused derived fuels (RDF), but also known for products such as RAL-certified mineral wool, is the establishment of a quality committee that ensures compliance with the quality assurance regulations.

In the Quality Committee, all major stakeholder groups should be represented by appropriate members; in addition, representatives of approval authorities and R & D.
As the players can also act as competitors on the market, the management of the quality committee should be represented through a “neutral institution” for organisation and coordination as well as for moderation, such as an institute of the University of Applied Sciences Bremen.

The quality committee awards quality seals for member companies that comply with the established standards. This must be demonstrated by successful participation in established certifications/checks.

The work of such a quality association bases on sufficient product declarations by manufacturers; in the case of the wind turbines, the main components have to be considered separately. The developed EPD-plus or the data requested should be regarded as a standard for members of the quality association, as far as they are not generally prescribed by the legislation in the future, especially for durable products.

Through an ongoing update of the evaluations, the quality association also creates a constant reassessment of the “old” EPDs evaluation. This recurring (re)evaluation alone meets requirements of recycling of durable products and thus also the responsibility of manufacturers.

In addition, an overview of the total stock of all wind turbines and their characteristics is of great importance for the work in the quality association. Only in this way material flows of the present and the future stock can be mapped or predicted and thus necessary processing and utilisation capacities can be estimated or shown. In the case of a lack of capacity, appropriate solutions should be discussed within the framework of the extended producer responsibility.

Tasks of a quality association
Preparation or setting of standards for the dismantling of wind turbines or the main components, for disassembling, processing and for the utilisation of the individual components, including any requirements for substitution of substances (see among other things lead balls as trim masses in the rotor blades) taking into account the ongoing development on the market (state of technology, alternative materials).

In order to assess recyclability of the main components and the overall system, definitions of recyclability, recycling and reutilization rates and derived control variables have to be defined and thus an evaluation of the overall WEA system shall be carried out in a process-based manner using resilience criteria (e.g. adaptability, redundancies).

In addition of assessing the recycling and reutilization rate, the use of LCA assessments or the CO2 footprint as a control parameter should also be used.


Definition of key figures / terms

For later control in the planned utilisation network, defined key figures or terms are necessary. In the context of the RecycleWind project, the following definitions have been defined in the context of the RecycleWind project, based on the long-standing discussions on recycling quotas and their definitions (e.g. KRUs) and recent definitions in European and German waste legislation (including commercial waste regulation):

  • The reutilization rate indicates how much of the waste product is actually used in the economy both materially and energetically. It displaces primary resources such as ores or crude oil through this use.
  • The recycling rate indicates how much of the waste product actually returns to the economic cycle. These are the quantities delivered to a production plant for reuse after recycling.
  • Secondary material quota indicates how much of pure secondary raw material can be returned from the recycled quantities to production. The quantities of recycling are further processed for use as secondary raw materials in the production plant; corresponding dirt and disturbing components, unusable portions (e.g. too short fibres) are separated. In metal trade it is the so-called rubble deduction.
  • Recyclability for a product indicates the mass of potentially recyclable substances in relation to the total mass, which can be supplied with or without disassembly and existing state-of-the-art processing techniques for a use as a secondary raw material for the purpose of origin or another purpose at the time of evaluation of the product.

In the RecycleWind project, recyclability is understood as an assessment of an entire system in which reuse and recycling of individual waste streams is possible through separation and disassembly of components and processing can be carried out through an existing infrastructure and organisation of the actors, so that high quality secondary material flows can substitute primary raw materials in a subsequent production process and can be circulated for as long as possible.

In the RecycleWind project, the measure for recyclability is currently the recycling rate, which has to be determined separately for the main components, with a distinction to be made always in terms of Mg or kg/product (main component WEA)

a. Recycling quota A high quality, i.e. for the purpose of origin, or high-quality cascade use
b. Recycling quota B for another purpose, including lower cascade use
c. Total recycling rate C as sum of a) and b)
d. Reutilization rate D energetic use (e.g. cement plant, MHKW)
e. Reutilization rate E as sum c) and d)

In course of the consistent data on the so-called “rubble deductions” in the use of recycled quantities the secondary material quotas should then replace the recycling quotas for the evaluation of the recyclability.

The amount on which the secondary material quota is based corresponds to the amount that is used to calculate the substitution quota. The substitution quota was proposed by the Resources Commisson at the UBA (KRU) to evaluate the the circular economy and indicates the share of secondary marterial in a product. The secondary material quota, as defined by us, looks at the circular economy from the point of waste, the substitution quota looks at the circular economy from the point of (new) product.

In case of a future establishment of a quality association RecycleWind, the aforementioned definitions of control parameters must be discussed by the members in the quality committee and then determined by majority decision.






RecyleWind • Recycling network - self-learning and resilient • IEKrW

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).