About This Article

This article examines how onshore wind turbine foundations are treated at the end of their operating life. Removal rules differ sharply between jurisdictions. Some require the whole foundation to be taken out, while others allow its deeper part to stay in the ground permanently, where its steel and concrete never re-enter material cycles.

The article sets out a recovery baseline that ranks reuse above recycling and treats partial removal as an exception that must be justified. It then outlines the changes needed in design approval, permitting and certification so that the baseline holds through changes of ownership and through decommissioning itself.

1. The Current Situation

1.1. Removal Rules Differ by Jurisdiction

In Germany, the Building Code requires anyone building a wind turbine in open countryside to commit to dismantling it and removing soil sealing once use ends (§ 35(5) BauGB). Most federal states and most legal commentary read this as requiring removal of the entire foundation. Partial removal is accepted only in individual cases, for example where extracting piles could contaminate groundwater [1]. Practice has moved towards this reading over time. Older permits often required removal only to a depth of about 1.5 metres, while the German Environment Agency reports a clear trend towards full removal in newer permits and land-use agreements [5].

Other markets set the line differently. In Denmark, a common permit requirement is removal of all equipment, including the foundation, to one metre below the surface [7]. In the United Kingdom, decommissioning requirements are set in the planning conditions of each project, so the removal depth varies from site to site [7]. In the United States, state and local standards set the depth, and the Department of Energy notes that communities often leave foundations partly in place because full removal has environmental impacts of its own [2]. The same guide cites foundations up to 20 feet deep, so a removal depth of a metre or so leaves most of the foundation where it is.

1.2. The Scale

Europe decommissioned 1.3 GW of wind capacity in 2024, more than half of it in Germany. WindEurope expects about 22 GW to be decommissioned between 2025 and 2030. Of that, around 12 GW should be repowered, and the remaining 10 GW removed from the system [3].

Every one of those turbines stands on a reinforced concrete foundation. Swedish gravity foundations built between 2013 and 2022 grew from about 350 to 1,150 cubic metres of concrete as turbine ratings doubled from 3.0 to 6.2 MW [4]. The older turbines now reaching end of life stand on smaller foundations. Even so, the volumes above mean thousands of foundations over the period, each holding hundreds of cubic metres of reinforced concrete.

1.3. What Partial Removal Leaves Behind

Where only the upper layer is removed, the reinforcement steel below it never reaches scrap markets, and the concrete is never processed into recycled aggregate. These materials are lost because of what the permit allows, not because recovery is impossible.

The land is constrained as well. A buried foundation obstructs later drainage, construction and deeper cultivation. Restoring full use of the land means excavating at a later owner’s expense, often long after the original project company has ceased to exist.

2. Why Full Removal Is Contested

Full removal has real costs. A conventional gravity foundation is either blasted, with charges set in holes drilled into the concrete, or broken up with a hydraulic chisel and excavated. The German Environment Agency reports that blasting usually takes two to three days, while chiselling proceeds at around 40 cubic metres a day, which is why most contractors blast larger foundations [5]. The US Department of Energy cites noise and ground disturbance, along with erosion and new pathways for water, as reasons communities accept partial removal [2]. German guidance likewise allows partial removal where full removal would do serious harm [1]. On deep peat, or where local drainage is fragile, full excavation can release more carbon and cause more lasting damage than leaving the foundation in place.

These objections are sound for the foundations built today. They arise because those foundations were designed to stay in the ground permanently. The answer is not to demolish every foundation regardless of harm. It is to require foundations that can be taken out without demolition, and to allow partial removal only where an independent comparative assessment shows it does less harm.

3. The Recovery Baseline

Recovery has an order of preference. Reuse comes first: the foundation, or the elements it is built from, carries a new turbine on the same site or elsewhere. Where reuse is not possible, full recovery comes next. The reinforcement steel returns to scrap markets, the concrete is processed into certified recycled aggregate, and the land is restored to match the surrounding soil and drainage. Partial removal comes last, and only where the assessment described above justifies it.

The outcome has to be settled before construction for any of this to hold. The design submission should include a documented dismantling method, together with evidence that the stated reuse or recovery yields can be achieved. Unless these conditions are set in advance and checked at the end, a claim of circularity carries little weight.

4. Repowering and Reuse

Repowering is where reuse matters most, and where it currently fails. On average, repowered wind farms treble their output with 25% fewer turbines [3], so the new turbines are far larger than the ones they replace. In the Swedish data, turbine ratings doubled in under a decade while foundation volumes more than tripled [4]. A foundation sized for an older turbine rarely carries its replacement.

Fatigue sets the second limit. DNV notes that foundations older than about ten years may not have been designed for fatigue at all, that fatigue damage accumulates, and that retrofitting a foundation is often difficult and costly. It recommends designing new foundations for 30 to 40 years instead of the usual 20 [6]. Armesto Barros and Mathern reach a similar conclusion. Reuse becomes realistic only if a longer service life is designed in from the start, or if the foundation’s remaining fatigue life is monitored during operation [4].

Reuse is therefore a decision taken at design stage. A foundation intended for reuse is rated for more than one turbine life, or built from elements that can be lifted out and installed again.

5. Institutional Correction

5.1. Design Approval

Design review currently confirms that a foundation will carry its loads, including fatigue, for its design life. It should also confirm what happens at the end of that life. Approval should require a dismantling method, the intended outcome in the order set out above, and projected reuse or recovery yields. The requirement concerns the outcome, not a particular design, and engineers remain free to meet it with whatever solution the site calls for.

5.2. Permitting

Permits decide whether recovery happens at all. Where a permit sets partial removal as the default, steel and concrete stay in the ground by design. Reuse or full removal should be the baseline condition, with exceptions limited to cases supported by an independent comparative assessment. Germany already treats full removal as the rule [1], which shows the requirement can be written into permits. Financial securities should be sized to the full outcome and released only against audited removal and processing results.

5.3. Certification

Certification bodies assess whether a foundation is safe. They do not yet assess whether it can be recovered. Adding the dismantling method and projected yields to certification criteria would turn recovery from voluntary reporting into a requirement that can be checked.

5.4. Disclosure

Each decommissioning should publish audited results: tonnes of steel recovered, the volume and grade of recycled aggregate produced, residual waste, and the area of land restored. Regulators need these figures to enforce the rules, and lenders and insurers need them to price end-of-life obligations.

5.5. Market Consequence

A foundation that can be reused or fully recovered carries a smaller and clearer end-of-life obligation than one that relies on partial removal. As decommissioning volumes grow, lenders and insurers can be expected to price that difference. Leaving material in the ground moves its cost into the future, often beyond the life of the company that built the project.

6. Synthesis

Onshore wind is being built and decommissioned at the same time, and the foundations approved today set the material outcome for decades. Germany shows that full removal can be required by law. The objections to full removal are real, but they describe foundations designed to stay in the ground, and they are not a reason to leave them there. Where reuse and recovery are required at approval and enforced at decommissioning, the steel and concrete in today’s foundations become feedstock for the next generation of turbines, and the land returns to use.

Part 2 of this series examines what it takes for a foundation to carry more than one turbine, and how design approval and certification in Europe would need to change to allow it.

Sources

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

[2] US Department of Energy. Wind Energy End-of-Service Guide. Link

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

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

[5] 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

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

[7] WindEurope (2020). Industry Guidance Document: Decommissioning of Onshore Wind Turbines. PDF

Cover image: reinforcement of a wind turbine foundation near Schonungen, Germany, 2011. Photo: Störfix, CC BY-SA 3.0 DE, via Wikimedia Commons.