Repowering UK Onshore Wind: Navigating the Planning and Consenting Landscape

Introduction  

As the UK accelerates its clean energy transition, repowering existing onshore wind sites is fast becoming a strategic priority. Thousands of first-generation turbines are nearing the end of their 20 to 25-year lifespan —around 5,000 expected by 2050^[1]—and the pipeline tells its own story. The UK’s onshore wind pipeline has surged by 4,313 MW in just 12 months, climbing from 42,745 MW in September 2024 to 47,058 MW by September 2025. Operational capacity is also on the rise, up from 15,566 MW to 15,827 MW, while projects under construction or consented have grown from 7,568 MW to 8,458 MW, signalling a sector firmly back on an upward trend after the historic low of 2020. ^[2] Scotland remains one of the top 20 countries worldwide for onshore wind capacity; it has 10,400 MW of operational capacity, with a further 1,700 MW in construction and 5,980 MW consented as at Q2 2025^[3]. Scotland hosts the majority of the UK’s onshore wind fleet and, as many early Scottish sites approach the end of their operational lives, the pipeline for repowering is deeper and more time‑critical than anywhere else in the UK. 

The opportunity is significant: repowering isn’t just replacement—it’s transformation. Modern turbines can deliver three to ten times more energy than older models^[4], often with fewer machines and a smaller footprint, helping to ensure “secure, home-grown renewable power”.^[5] Recent projects demonstrate what this transformation looks like in practice: in late 2024, ScottishPower successfully completed the full repowering of Scotland’s first commercial wind farm at Hagshaw Hill, replacing 26 ageing turbines with just 8 modern machines capable of producing twice the energy of the original site. The project not only extended the life of a cornerstone of Scotland’s renewable landscape but showcased the carbon, economic and efficiency gains that repowering can unlock at scale^[6]. Unlocking that potential hinges on navigating a complex planning and consenting landscape; anticipating environmental and community obligations, aligning with policy reforms and proactively engaging with regulatory opportunities.

Policy Context and Moment

Against this backdrop, understanding the evolving policy framework and regulatory drivers is critical—because they will ultimately shape how, and how quickly, repowering projects move from concept to consent.

Policy support for repowering has never been stronger, but the devil is in the detail. In England, the National Planning Policy Framework (NPPF) now gives repowering projects a clear edge: they’re exempt from the old hurdles of express development plan allocation and explicit community support, which so often tripped up new onshore wind. Local Planning Authorities are directed to back repowering applications where “impacts are, or can be made, acceptable”.^[7] The government’s Clean Power 2030 Action Plan^[8] and the lifting of the de facto ban on onshore wind signal a decisive shift, but the legislative machinery will take time to catch up. For now, projects above 100MW are set to be routed through the Nationally Significant Infrastructure Project (NSIP) regime under the Planning Act 2008, streamlining the process for large-scale schemes, while sub-100MW projects remain with local authorities.

North of the border, Scotland is setting the pace. The Onshore Wind Policy Statement (December 2022) and National Planning Framework 4 (NPF4) are unequivocal: Policy 11 actively encourages all forms of renewable energy, with explicit support for repowering, expansion, and life extensions. The Scottish Government’s 20GW by 2030 target is ambitious, and the sector is now rapidly approaching the point where delivering substantial new capacity before that deadline becomes increasingly challenging. By contrast, repowering schemes are uniquely placed to deliver at pace. They are located on sites that have already demonstrated they can host a wind project, often benefit from existing grid and transport infrastructure, and typically face fewer unknowns in assessing the environmental baseline and community engagement. As a result, repowering is fast becoming the most bankable pathway for Scotland to close the gap to its 2030 ambition. 

The planning system is being recalibrated to deliver—placing socio-economic benefits and climate priorities at the heart of decision-making. Wind projects in Scotland 50 MW or above fall under the Section 36 Electricity Act regime, where applications are determined by Scottish Ministers and typically accompanied by deemed planning permission. Smaller schemes (below 50 MW), follow the Town and Country Planning (Scotland) Act 1997 via local planning authorities. However, that dividing line may soon shift. The Scottish Government’s late‑2025 consultation proposes raising the Section 36 threshold to either 100 MW or 150 MW, recognising that turbine capacities and site scales have evolved dramatically. If implemented, this reform would move a greater proportion of repowering schemes into local authority control—a significant structural change in how onshore wind is delivered in Scotland. For developers and stakeholders alike, the message is clear: the policy winds are blowing in favour of repowering, but success will depend on early, strategic engagement with the evolving rules of the game.

Regulatory Updates: Scotland and England

In England, the NPPF was updated in February 2025, following the July 2024 policy statement, to remove the previous carve-out and treat onshore wind (including repowering) on the same basis as other energy developments. Local decision-making still hinges on site-specific harm-benefit analysis and up-to-date cumulative context.

In Scotland, explicit national policy support is set out in the Onshore Wind Policy Statement (2022) and NPF4 (2023), with ongoing reforms to Section 36/36C processes under the Planning and Infrastructure Bill (2025) aiming to further streamline and clarify the consenting process for large-scale projects. Across both regimes, expect continued emphasis on robust EIA justification, cumulative clarity, and the practicalities of aviation lighting for taller machines.

Consent Strategies: Choosing the Right Route

Selecting the optimal consent pathway is a strategic decision that shapes project timelines, risk, and evidential requirements. For most onshore repowering schemes, a new planning permission or consent will be required.

Seeking new planning permission or consent: The Most Likely Route

Most repowering proposals involve replacing older turbine models with substantially more advanced (i.e. larger) models, usually on new foundations, with new layout configurations, upgraded access and often enhanced grid infrastructure — as such, the majority of projects will require a fresh planning permission or a new Section 36 consent, rather than a variation of existing consents. Variations remain possible in limited cases, but they are generally the exception, not the norm.

England: A new planning permission will normally be required under the Town and Country Planning Act 1990. Projects exceeding 100 MW must now enter the Development Consent Order regime under the Planning Act 2008 following the Infrastructure Planning (Onshore Wind and Solar Generation) Order 2025, which reinstated onshore wind into the system from 31 December 2025.

Scotland: Schemes ≤ 50 MW require a new planning permission under the Town and Country Planning (Scotland) Act 1997. Schemes > 50 MW require a new Section 36 consent under the Electricity Act 1989, accompanied by deemed planning permission under Section 57. As noted above, the new Scottish Government consultation proposes raising the Section 36 threshold to 100 MW or even 150 MW, so developers should engage with any legislative reform that comes out of this consultation. 

A new application allows developers to address new turbine dimensions, revised site layouts, changed environmental baselines, increased capacity, and updated technical mitigation — all of which typically exceed the permissible scope of a variation. It also offers a cleaner legal foundation for the life of the repowered project.

Varying existing planning permissions (Section 73 in England, Section 42 in Scotland): Narrow Use Only.

While these mechanisms allow a developer to seek a new permission with varied conditions, recent case law has reiterated just how limited their scope is.

Test Valley Borough Council v Fiske [2024] EWCA Civ 1541 clarifies that Section 73 applications may only vary conditions where the resulting permission remains fully consistent with the operative part of the original planning permission; the description of development and including any plans incorporated into it. Although the Court made clear that the scale of the proposed change is not the limiting factor, a Section 73 application cannot be used where the variation would require amending the description of development or otherwise altering the operative scope of the consent. In the context of repowering, where the description of development or incorporated plans specify turbine numbers, dimensions, or layouts, substantial changes—such as replacing turbines or revising infrastructure—will generally fall outside the scope of Section 73 and require a new planning application. It’s therefore highly unlikely, in practise, that repowering projects can take advantage of this route unless they are looking at lifetime extensions or minor optimisations rather than substantial replacement of infrastructure or installation of new turbines.

While the Scottish legislative power to vary is more flexible in principle than its equivalent provisions in England, Section 42 still creates a new standalone planning permission, meaning the planning authority must assess the proposal against the current development plan and material considerations. In practice, substantial repowering schemes will almost always fall outside what is appropriate for Section 42.

Section 36C Variations (Scotland Only) — Increasingly Structured, but Still Limited

Section 36C provides a mechanism to vary an existing Section 36 consent in Scotland. It can authorise operational changes or modest refinements to previously consented generating stations. However, Section 36C cannot be used to authorise repowering that would effectively create a new generating station, such as replacing a fleet of older turbines with larger, more powerful machines or changing the core site configuration. These changes require a new Section 36 application, not a variation.

The Scottish and UK Governments’ joint Electricity Infrastructure Consenting Reform proposals (currently not in force) would introduce structured pre‑application consultation and clearer variation pathways under Section 36C, but these will not change the core principle: Section 36C is not the route for full repowering; it is for incremental variation only.

Key Planning Issues and Challenges

Decision-makers are applying heightened scrutiny to several recurring themes in repowering cases:

• Landscape and Visual Effects: While repowering often means fewer, larger turbines, increased tip heights can expand visibility zones and alter landscape character. Aviation lighting requirements above 150 metres can introduce new night-time effects.
   
• Cumulative Impacts: Applications must reassess cumulative impacts against the current baseline, considering other consented or proposed schemes that may not have existed at the time of the original permission.
   
• Efficiency and Viability: The system benefits of higher capacity factors and fewer turbines are increasingly argued as material planning considerations, especially in a post-subsidy context, though their weight depends on local policy and evidence.
   
• EIA Assessment Baseline: This is a developing area. As a matter of environmental assessment, repowering proposals are typically assessed against a “no scheme” baseline—that is, on the assumption that the original wind farm has been decommissioned and the site restored in accordance with its consented decommissioning plan. This means applicants cannot rely on existing operational turbines to reduce the significance of effects or argue that local communities are already “used to” current landscape and visual impacts. In EIA terms, the baseline is the restored site, not the currently operational one. However, the existing consent and long‑established use of the site for renewable energy remain material considerations, and can support the argument that the principle of development of that nature and scale is already accepted in planning terms. NatureScot similarly advises the EIA baseline should assume a restored site, even where repowering retains elements of existing infrastructure.

Beyond these headline areas, technical topics such as noise, shadow flicker, peat and soils, hydrology, biodiversity, ornithology, transport, aviation, radar, and cultural heritage all require updated assessments tailored to the repowered configuration and the current cumulative environment. Grid and system considerations, including upgrades to connections or shared infrastructure, may also prompt new consent obligations.

Practical Considerations and Recommendations

A robust repowering strategy hinges on the alignment of planning, environmental impact assessment, and stakeholder engagement. Early scoping with planning authorities and targeted consultation with statutory bodies can help de-risk key issues such as aviation lighting, landscape capacity, and ecological receptors. Applicants should:

1. Clearly evidence the consolidation narrative with visualisations of turbine reductions and layout efficiencies (or, alternatively, evidence why the site can and should see its generation capacity maximised with a similar number of more powerful turbines).
    
2. Transparently address any increased scale and its implications.
    
3. Recalibrate cumulative assessments using the latest data, capturing neighbouring applications to pre-empt objections.
    
4. Define and justify the EIA baseline explicitly, ensuring the repowered scheme is assessed as a standalone proposal.
    
5. Consider whether a variation or new permission route best accommodates the scale of change.
    
6. Maintain careful management of land, grid, and shared infrastructure interfaces to avoid misalignment that could undermine deliverability.

Conclusion

Repowering onshore wind is now a core part of the UK’s clean power strategy, leveraging existing sites and connections while modernising technology to improve output. Success in planning terms depends on early, strategic consent route selection, a disciplined EIA and cumulative approach, and transparent engagement on landscape, visual, and aviation lighting effects. With supportive policy signals in both England and Scotland, and clearer pathways for variations, new permissions, developers who anticipate the scrutiny themes above and tailor their evidence accordingly will be well placed to secure timely consents for the next generation of onshore wind.

Co-authored by Poppaea Watt, Associate in our Energy & Infrastructure Planning team.
 

^[1] The future of onshore wind decommissioning in Scotland

^[2] UK onshore wind pipeline report 2025

^[3] Scotland’s onshore wind - a mature, investable asset class

^[4] Nadara_Repowering_FactSheet_v4

^[5] ^^

^[6] ScottishPower successfully completes repowering of Scotland's first wind farm, 30 years after its initial commissioning - Iberdrola

^[7] Policy statement on onshore wind - GOV.UK

^[8] Clean Power 2030: Action Plan: A new era of clean electricity