Wind Farm Repowering

Overview

A working guide for replacing the turbines on an existing French wind farm — what survives from the original consent, what has to start again, and the single question that decides which.

French law has exactly one repowering-specific instrument, and it is worth understanding what kind of thing it is. It creates no procedure. It instructs prefects how to apply the ordinary modification machinery to repowering, and sets the criteria that divide a notable modification — a filing — from a substantial one, which means a complete fresh environmental authorisation. That distinction decides the whole timetable, and the instrument dates from March 2026. It abrogates and replaces both of its predecessors, including one issued only the previous September. Any advice resting on the older thresholds describes a regime that no longer exists.

The criteria themselves are unusually workable. Five configurations are named, from like-for-like replacement through longer blades at the same tip height, taller masts, relocation, and additional machines. A polygon is defined by the discs your existing turbines already occupy, and moving outside it changes the answer. Height changes are banded: below roughly a third is treated as notable, above a half for any single machine as substantial, and the space between is judged case by case, with a reduction in the number of masts capable of counting in your favour. Certain cases are automatically substantial whatever the merits, and those are set out.

The most valuable structural feature is the baseline. Impacts are assessed differentially against the farm as authorised and already operating, not against a bare site — which is precisely the comparison that makes repowering viable where greenfield would not be.

On the money, the research initially concluded there was no repowering-specific provision in the support regime at all. That was overstated, and the correction matters more than the original finding: a second paragraph of the tender eligibility clause expressly admits installations already holding a premium-contract application or an advance-signed contract, and allows the characteristics stated in the bid — capacity and number of masts among them — to differ from those in it. That is an explicit route out of an old support position into the auction with a redesigned plant. The same document carries a completion-deadline extension for the duration of any litigation, which in this jurisdiction is not a footnote.

Two limits are on the page rather than buried. The governing circular is a scanned document, and nobody in the chain read it in its signed form; every quotation traces to one agency’s transcription, independently corroborated on the load-bearing points but still a single source. And one assessment annexe is a multi-column table that the research tooling flattens, destroying column membership — two verification passes reached opposite conclusions from the same page. The answer is still determinable from how the provision is drafted, and it is published as an inference from the drafting rather than as something read.

What this edition covers

Twenty parts across the full repowering sequence — the map, the notable-or-substantial test, the five configurations, the polygon, the height bands, the automatic cases, the blades-only route, the differential baseline, environmental assessment, species and habitats, radar and aviation, noise, the grid connection, losing the old contract, the migration path, the tender, dismantling, the guarantee, blades and recycling, and pitfalls — followed by a tear-out field checklist, an indicative French timeline, a glossary, a note on sources, a full index, the reference register and a France repowering screening layer.

Who this is for

Owners, developers, investors and lenders replacing the turbines on an existing French onshore wind farm.

What you get

• Practical repowering guidance, not market sizing
• The single test that decides whether you file a notice or start again
• Five configurations, and which side of the line each falls on
• The polygon your existing turbines already define
• Height bands at a third and a half, and the zone between them
• A 2026 circular that replaced its 2025 and 2018 predecessors outright
• Impacts assessed against the farm already turning, not an empty field
• The eligibility paragraph that carries an old support position into the auction
• A litigation extension in the tender that most summaries omit
• Dismantling, foundation depth and the guarantee, with its indexation

Table of contents

1. How to use this guide: A working document for French repowering, read in the order the prefect decides things.
2. Part 0 — The Map: Prefect, inspectorate and the ministry circular that tells them how to think about you.
3. Part 1 — One Question Decides Everything: Notable or substantial — and why that single word sets your entire timetable.
4. Part 2 — The Five Configurations: Like-for-like, longer blades, taller masts, relocation, added machines — and how each is treated.
5. Part 3 — The Polygon: The shape your existing turbines already define, and what happens when you step outside it.
6. Part 4 — The Height Bands: Under a third, over a half, and the judgement zone between them.
7. Part 5 — Automatically Substantial: The cases where no argument helps and a full new authorisation is the only route.
8. Part 6 — Blades Only: Keeping tip height and changing everything else, and the four proofs that route demands.
9. Part 7 — The Differential Baseline: Assessed against the farm that is already turning, not against an empty field.
10. Part 8 — Environmental Assessment: What is screened and what is automatic, and a table this tooling could not read.
11. Part 9 — Species and Habitats: Derogations on a site that has been operating for years, and the survey they expect.
12. Part 10 — Radar, Aviation and Defence: The consultations that quietly decide whether longer blades are possible at all.
13. Part 11 — Noise: Measured against the operating farm, and what larger machines have to prove.
14. Part 12 — The Grid Connection: What survives, what has to be re-applied for, and what extra capacity costs.
15. Part 13 — Losing the Old Contract: What repowering does to existing support, and why that is the real decision.
16. Part 14 — The Migration Path: The eligibility paragraph that lets a redesigned plant carry an old position into the auction.
17. Part 15 — The Tender: Periods, deadlines, the litigation extension, and the term that shortens with them.
18. Part 16 — Dismantling the Old Machines: Who owes it, when it bites on a repowering, and how deep the foundations come out.
19. Part 17 — The Guarantee: What must be posted, how it is calculated and indexed, and what happens to it on repowering.
20. Part 18 — Blades and Recycling: Recovery obligations on the machines you are taking down.
21. Part 19 — Pitfalls: Twelve ways a French repowering goes wrong, starting with using the 2018 thresholds.
22. The Field Checklist: Tear-out — every filing, consultation and consent a French repowering needs, in order.
23. Appendices — Timeline, glossary, sources, index, references and the France repowering screening layer: A repowering timeline measured from the day the old machines stop, a glossary, a note on sources, a full index, the reference register, and the screening layer.

Research and sources

Every instrument named in this edition is cited to its own article or clause, the version read, and the database it was read at. Two limits are stated rather than hidden. The governing circular is a scanned document that nobody in the chain read in its signed form: every quotation traces to one agency’s transcription of that scan, independently corroborated on the height bands, the polygon definition, the response deadline, both abrogations and the non-citation clause — but it remains a single source, and the circular additionally mis-cites its own legal basis, which is reported as observed. And one assessment annexe is a multi-column table that this tooling flattens; two verification passes reached opposite verdicts from the identical page, so the conclusion drawn from it is published as an inference from the drafting rather than as a reading. Where the research understated a finding — concluding no repowering provision existed in the support regime when an eligibility paragraph expressly provides one — the correction is on the row. Nothing here was reviewed by a French-qualified lawyer, and anything intended to carry a decision should be re-read against its own instrument on the day it is relied on.

Licensing

Single-user licence. For use by the named licensee only. Redistribution, resale, posting to shared drives or internal circulation beyond the named licensee is a breach of licence. Team licences covering up to five named users are available.