Ageing wind farms: Navigating challenges and unlocking opportunities

A substantial number of Scottish wind farms are nearing the end of their intended operational life. This is evidenced by the recent approval to repower the initial phase of Windy Standard, one of Scotland’s longest-standing wind farms.

With an estimated 1.6 gigawatts (GW) of renewable energy capacity anticipated to reach the end of its planned operational lifespan by 2030, it is evident that onshore wind developers now face a fundamental question: what strategic opportunities and challenges now lie ahead for Scottish onshore wind farms?

The end-of-life decision

Typically, developers face three main choices at the end of a wind farm’s intended operational life:

1. Decommissioning: This involves dismantling the site, removing turbines and infrastructure, and restoring the land, as required by the lease terms or planning consents.
2. Life extension: Developers may seek to extend land rights and planning permissions, which are often originally limited to 25 years, and potentially upgrade or replace turbine components.
3. Repowering: Repowering entails removing existing turbines and installing new ones, often with improved technology and greater capacity. Upgrades can lead to outputs between three and ten times greater depending on site conditions and turbine type. RenewableUK forecasts that repowering sites at the end of their operational life could contribute to 1.2GW of new wind capacity by 2030. Extending the life of a wind farm or repowering is a “win-win” as it allows for continued use of some of the highest yield sites, provides economic benefit to local communities and means that the developer can continue to use the existing infrastructure, and therefore significantly reduce the carbon footprint of the site, whilst maximising profit.

As older wind farm sites typically have a higher wind yield, they are usually well placed to take advantage of repowering opportunities. Repowering can also provide an opportunity to co-locate another technology by including solar, battery storage or hydrogen electrolysers.

Key legal and commercial considerations

1.     Additional land rights

Repowering often involves installing larger turbines. Developers should look to assess whether existing land rights are sufficient to permit redevelopment. They may need to negotiate:

• Additional access rights for overrun or over sail to accommodate the transportation of larger components
• Extended wind protection zones

These negotiations may involve additional third-party landowners who weren’t affected by the original development.

The original lease term – typically between 25 to 30 years – will also need to be extended. Wind farm leases may include provisions that allow for lease extensions; however, this is not always the case. It should also be kept in mind that any lease extension provisions were most likely negotiated over 30 years ago, with wind farm leases having evolved considerably over the past decades, therefore we recommend that advice on any extension provisions is sought at an early stage.

Developers can utilise several routes:

• Using existing extension rights: If the lease includes a clear and workable extension clause – specifying terms and rent – extending the lease may be straightforward.
• Negotiating a lease extension or new lease: Where no express extension rights exist, or where there is an option to extend subject to a suitable rent being agreed between the parties then developers may need to negotiate with landowners. This could involve varying the existing lease or agreeing on a new one. Given the evolution of wind farm leases over the past decades, these negotiations can be complex.
• Securing an option agreement: In many cases, it’s beneficial to negotiate an option for a new lease or an extension. This provides flexibility, especially if planning consent or a Contract for Difference (CfD) allocation is required before proceeding.

2.     Planning considerations

In Scotland, wind farms over 50MW require consent from the Scottish Ministers under Section 36 of the Electricity Act 1989. Re-powered proposals over 50MW will be required to make a new application.

If under 50MW, a new planning application must be made to the relevant planning authority.

Planning obligations (Section 75 in Scotland or Section 106 in England) may also need to be updated to accommodate the re-powered scheme.

3.     Grid connection

Existing wind farms have grid connection agreements. If repowering increases capacity, developers must apply for a new or upgraded connection. Even if capacity remains unchanged, changes to equipment require notification to the grid operator and may necessitate modifications to the connection agreement.

Given current grid queue delays, early applications for additional capacity are advisable.

4.     Contracts for Difference (CfD) revenue support

Repowered wind farms may now qualify for CfD support. In January 2024, the UK Government consulted on including repowering projects in future CfD allocation rounds and this has been refined for the AR7 allocation round. Key eligibility criteria include:

• The project must have reached the end of its operational life (for onshore wind this has been set at 25 years from commercial operation) and not be receiving other subsidies.
• The existing project must be decommissioned to qualify.
• The project must align with the CfD’s rationale, including high upfront capital costs.

5.     Power Purchase Agreements (PPAs)

Developers must ensure compliance with existing PPAs, which often include capacity obligations. These help offtakers forecast output and manage risk. Repowering may require notifying offtakers about capacity changes to ensure smooth transitions and efficient management of the wind farm.

Key takeaway

As Scotland’s onshore wind sector matures, the transition from legacy infrastructure to next-generation renewable capacity presents both a challenge and an opportunity. Developers must navigate a complex matrix of legal, planning, and commercial considerations to ensure that repowering or life extension strategies are viable and sustainable. With the right approach, grounded in early engagement, robust legal frameworks, and strategic planning, these projects can continue to deliver clean energy. The decisions made today will shape the trajectory of Scotland’s renewable landscape for decades to come.

How can we help

Anderson Strathern advises developers across Scotland on the legal, planning and commercial aspects of wind farm repowering and life extensions. Our team can support you in areas such as navigating lease negotiations, planning applications, grid connection updates and subsidy eligibility.

For tailored advice on your project, please contact Iain Baird (iain.baird@andersonstrathern.co.uk) or a member of our Energy & Renewables team.