Constructing a route to repowering 

Repowering, the practice of bolstering the output of existing renewable energy projects, is rapidly moving from a theoretical end-of-life question to a pressing delivery priority. 

More than half of the UK’s onshore wind fleet is expected to face decisions on life extension, decommissioning or repowering by 2035. Modern equipment can increase output at sites which already have established land rights, grid infrastructure and operating histories.

However, that head start can be misleading. Repowering is not simply a new-build project using better technology. Rather, it is a more complex integration exercise in which new works must be delivered through existing assets, live operations and legacy contracts.

This mix of new kit and legacy arrangements creates a number of issues for the procurement and construction of any additional plant. 

A key concern to be considered at each stage of any repowering is the responsibility gap between what is already there and what the repowered project requires – and this should drive the procurement strategy. But even if developers alight on a favoured approach, they face strong competition for specialist contractors and key components. 

Here, we share some suggestions as to how to ensure your repowering doesn’t punch below its weight. 

Start with the legacy position

Firstly, technical due diligence must establish whether existing roads, crane pads, foundations, cables and substations can support larger equipment, heavier lifts and revised electrical requirements. Records may be incomplete and original design assumptions may no longer be appropriate. Ground investigations, structural assessments and testing should therefore inform the design before bidders are asked to price the risk.

Contractual due diligence is equally important. Existing O&M arrangements may contain break rights, compensation mechanisms, change procedures and restrictions on third-party access. Their liability caps may also be lower than under a standalone construction contract. Using the incumbent O&M contractor can preserve knowledge and continuity, but substantial works should not be placed under an O&M contract without testing whether its design obligations, remedies, security and insurance are fit for purpose.

Consider your interface risk

The turbine suplier/OEM, balance-of-plant contractor, operator, network operator and decommissioning contractor may each control part of the critical path for the delivery of the additional capacity. The difficult risks sit between their scopes: shutdowns, access, temporary works, protection settings, removal, testing and energisation. Shared sites or connections make those dependencies more pronounced.

An interface matrix is a useful document for tracking such interfaces - identifying deliverables, dependencies and the consequences of failure. Programmes, relief events and cooperation obligations must align. Completion tests should distinguish defects in the new works from failures caused by retained equipment or the network. Describing a contractor as “lead” adds little unless its responsibility matches its ability to control the other participants.

Protecting ongoing operations (and income)

On operational assets, works may be phased around continuing generation, constrained by agreed outage windows or undertaken while new equipment is temporarily downrated to the existing connection capacity. Site rules must establish operational control, isolation procedures, emergency arrangements and the boundary between construction and operational health and safety responsibilities.

The contractual regime will have to consider both completion delay for the new infrastructure and the consequences of interference with the operating asset. A prolonged outage may cause immediate lost revenue even if final completion is achieved on time. Liquidated damages, liability caps and exclusions should therefore be considered alongside ‘delay in start-up’ and business interruption cover and tested against the project’s revenue arrangements.

Treat dismantling as part of construction

The dismantling of existing plant should be integrated into the construction sequence. Contracts should allocate responsibility for removal, storage, waste classification, transport and lawful recovery or disposal. They should also address title and risk in removed equipment, including whether a contractor bearing disposal cost should share in the residual value of reusable components. This is particularly relevant to turbine blades, as composite materials remain difficult and costly to process.

Early market engagement is also important, particularly for smaller projects competing for specialist contractors and long-lead equipment. Existing financing and revenue documents may restrict variations or require lender consent. Eligible repowered onshore wind projects can now participate in the Contracts for Difference scheme, strengthening the investment case but placing greater importance on a credible delivery programme.

Repowering can unlock more output from proven sites, but only if existing assets, contracts and operational interfaces are understood. The successful repowering projects will be those who understand that such efforts must navigate existing challenges, and are not a shortened new-build.

Burges Salmon

We have advised on repowering projects across wind, solar, hydro, EfW and other technologies for many years and have been gearing up to meet the substantial challenges existing projects face in repowering alongside already substantial project build out programmes across the UK.  Our experience and early thinking on the issues affecting repowering are likely to substantially assist you in your repowering strategy.

We have already provided thoughts on other issues affecting repowering projects in recent articles (link here: Repowering Onshore Wind: Opportunity, Urgency and the Challenge of Delivery - Burges Salmon ) and are excited to speak with you about how we can meet the challenges ahead.

If you would like to speak with us about any repowering related matters then please contact us. You can also find our ‘Repowering in Conversation’ series here: Repowering In Conversation series - Burges Salmon

This article was written by Lloyd James, Mark Summers and Muhammad Abolarin.