About This Article

Part 1 of this series set out a recovery baseline for onshore wind foundations that ranks reuse above recycling. This article asks what it takes for reuse to happen: for one foundation, or the elements it is built from, to carry more than one turbine.

The main obstacles in Europe are not in the engineering. They lie in the rules that approve foundations, classify what comes out of the ground and secure its removal. The article describes those obstacles and the changes that would remove them.

1. Why Foundations Are Single-Use

1.1. Designed for One Turbine

In Germany, foundations are approved under the building authority’s guideline for wind turbines, which requires a design life of at least 20 years [4]. The international standard for towers and foundations, IEC 61400-6, likewise designs the support for one turbine over a planned life [9]. The concrete itself lasts far longer. Researchers at Lund University point out that turbines typically operate for around 20 years, while concrete foundations can last a century or more [10]. What ends a foundation’s life is the design basis, not the material.

1.2. Replacement Turbines Outgrow Them

Repowering replaces old turbines with far larger ones. On average, repowered wind farms treble their output with 25% fewer turbines [1]. In Swedish data, turbine ratings doubled between 2013 and 2022 while foundation volumes more than tripled [2]. DNV notes that foundations older than about ten years may not have been designed for fatigue at all, and that fatigue damage accumulates over time [3]. The result is that a repowered site usually gets a new foundation beside the old one.

Even when a turbine is sold on and moved to a second site, the foundation does not move with it. The German Environment Agency describes how the steel part that connects tower to foundation is sometimes removed with care, checked, and set into a new foundation at the second site [6]. The turbine moves on to a second life, while its foundation is built again from scratch.

2. What a Reusable Foundation Has to Show

A foundation intended for reuse has to meet three conditions, and each has to be shown at design approval rather than claimed later.

The first is capacity beyond one turbine generation. The design life and load range have to cover the turbines likely to follow, not only the first. DNV recommends designing new foundations for 30 to 40 years instead of 20 [3]. Armesto Barros and Mathern conclude that reuse becomes realistic only if a longer service life is designed in from the start, or if remaining fatigue life is monitored during operation [2].

The second is removal and reinstallation without loss of capacity. Where a foundation is meant to move, its elements have to come out of the ground and go back in on another site without damage. Where it is meant to stay, it has to take a new turbine without being rebuilt.

The third is a continuous condition record. Fatigue damage accumulates [3], so every reuse depends on knowing what the foundation has already been through. Inspections, repairs and load history have to be recorded from the first installation, and the record has to pass with the foundation from one owner to the next.

These conditions describe outcomes, and different designs can meet them. None of them is out of reach for engineering today. The difficulty is that European rules have no settled place for any of them.

3. Where European Rules Stand in the Way

3.1. Approval Assumes a Single Life

The German guideline provides a procedure for assessing whether an existing turbine can keep running beyond its design life, by recalculation or by inspection [4]. IEC TS 61400-28, published in 2025, sets requirements for extending the life of existing wind assets [5]. Both concern keeping an asset in service where it stands. Neither, in its published scope, provides a route for approving a foundation, or elements of one, to carry a different turbine or to be installed again on another site. A developer offering a reusable foundation therefore has to argue its case afresh at each approval, in a framework with no category for it.

3.2. Waste Law Decides Whether an Element Stays a Product

The EU Waste Framework Directive ranks preparing for re-use above recycling [8]. It also draws a line that matters for foundations. Re-use applies to items that never became waste, while preparing for re-use applies to items that already have [8]. Once an element counts as waste, moving it to another site brings waste handling and permitting with it.

Which side of that line an element falls on depends on its holder’s intention. The Court of Justice has held that an object escapes waste status only where its reuse is certain, not merely possible. In Tronex, it required the holder to check that returned goods could be reused for their original purpose without repair [11]. German law applies a similar test. The Circular Economy Act presumes an intention to discard where an object’s original purpose ends without a new purpose immediately taking its place [12].

A foundation element can therefore remain a product, but only if its next use is settled before it leaves the ground. An element removed under a documented plan to reinstall it, with its condition checked, has a new purpose that takes the place of the old one. An element removed without such a plan risks being treated as waste, and must then pass through waste recovery before it can be used again.

The EU Construction Products Regulation, which applies from January 2026, now brings used construction products within its scope, provided they are not waste [13]. It notes that requirements for previously used construction products vary widely between Member States, and it provides for dedicated harmonized specifications to cover them. Each standardization request must state whether it covers used products [13]. Whether foundation elements are included therefore depends on requests that have yet to be made for them.

3.3. Securities Price Removal, Not Reuse

German permits require a security to cover dismantling, and the approving authority has wide discretion over how it is calculated. Practice varies widely between federal states, removal costs are hard to forecast, and there have been repeated calls for a standard method [7]. The calculation starts from the cost of removal. A foundation whose elements keep their value and move to another project changes that cost, but the calculation has no place to recognize it. The same guidance notes that securities have to allow for a change of operator [7]. A reusable foundation needs its obligation and its condition record to pass to the next owner together.

3.4. Repowering Permits Are Speeding Up

The revised Renewable Energy Directive calls on Member States to complete permitting for repowering projects within one year [1]. Faster permitting means more foundation decisions in less time. An approval route for reuse, settled in advance, fits that timetable far better than a case argued from first principles on every site.

4. What Would Close the Gap

Design approval needs a route for foundations designed for more than one turbine generation, including a procedure for requalifying reused elements. It can build on the life-extension methods that already exist in the German guideline and in IEC TS 61400-28 [4][5].

Waste law needs a recognized form for the reinstallation plan. EU case law and German law already point towards treating planned, checked reuse as a new purpose rather than disposal [11][12]. What is missing is a standard plan that waste and permitting authorities accept as that proof.

Securities need a calculation that recognizes an approved reuse plan, so that the security reflects the actual end-of-life outcome rather than a default of demolition.

The condition record needs to be kept independently of any single owner, so that it survives changes of ownership and supports every later approval.

None of these measures requires new technology. They require open standards that engineers, certification bodies and permitting authorities can all review and apply in the same way.

5. Synthesis

The engineering case for reusable foundations has been made in research, and designs for reuse exist. What is missing in Europe is a clear route through approval, waste law and securities. The first reusable foundation systems to reach European sites will face that gap directly, and the terms on which it is closed will shape the market that follows.

Circular Energy Infrastructure contributes to open standards for the circularity of energy infrastructure, so that engineers and authorities can review them. CEI caters to the institutional side of end-of-life recovery: approval routes, obligation frameworks and the records that carry them from one owner to the next.

Sources

[1] WindEurope (2025). Wind Energy in Europe: 2024 Statistics and the Outlook for 2025–2030. Link

[2] Armesto Barros, J. and Mathern, A. (2022). Recent and future trends of onshore wind turbine foundations. IABSE Symposium Prague 2022. PDF

[3] DNV (2018). Foundations for success: three steps to full turbine repowering from the bottom up. Link

[4] Deutsches Institut für Bautechnik (2012, corrected 2015). Richtlinie für Windenergieanlagen: Einwirkungen und Standsicherheitsnachweise für Turm und Gründung. Sections 8 and 17. PDF

[5] IEC TS 61400-28:2025. Wind energy generation systems – Part 28: Through-life management and life extension of wind power assets. Link

[6] Zotz, F., Kling, M., Langner, F., Hohrath, P. et al. (2019). Entwicklung eines Konzepts und Maßnahmen für einen ressourcensichernden Rückbau von Windenergieanlagen. UBA Texte 117/2019. Umweltbundesamt. PDF

[7] Roscher, M. (2021). Rückbau von Windenergieanlagen: Ein Blick auf die Rückbauverpflichtung und weitere städtebauliche Instrumente. Fachagentur Windenergie an Land. PDF

[8] Directive 2008/98/EC on waste (Waste Framework Directive), Articles 3 and 4. Link

[9] IEC 61400-6:2020. Wind energy generation systems – Part 6: Tower and foundation design requirements. Link

[10] Mohamed, W., Austrell, P. E. and Dahlblom, O. (2017). A new and reusable foundation solution for onshore wind turbines. Proceedings of the 2nd World Congress on Civil, Structural, and Environmental Engineering. Link

[11] Court of Justice of the European Union, Case C-624/17, Tronex, judgment of 4 July 2019, ECLI:EU:C:2019:564. Link

[12] Kreislaufwirtschaftsgesetz (KrWG), § 3(3) and § 3(21). Link

[13] Regulation (EU) 2024/3110 (Construction Products Regulation), recital 34, Article 2(1), Article 3(20) and Article 5. Link

Cover image: wind turbine foundation under construction between Pfiffelbach and Ködderitzsch, Thuringia, Germany, May 2025. Photo: Thuringius, public domain (CC0), via Wikimedia Commons.