Why 2027 could be a watershed for investors in ageing UK onshore wind and solar PV assets
With 2.6GW of onshore wind set to roll off the Renewables Obligation scheme next year, uncertainty over its future market design creates fertile ground for investors able to unlock latent value.
In 2027, an initial wave of 2.6GW of onshore wind will exit the Renewables Obligation scheme to operate as merchant plants, while DESNZ considers fundamental changes to the scheme’s market design. A second wave of exits in 2033 includes solar PV assets. Exiting the scheme means losing access to certificates whose sale currently accounts for a substantial share of a generator’s revenue: a median of 41% for onshore wind and 49% for solar PV. Together with the uncertainty over future certificate market rules, this could weigh on asset values as support expires. This shift in project economics could offer acquisition opportunities for investors able to identify and unlock latent value across three investment theses: resilient merchant tail, repowering play, and energy hub optionality.
The Renewables Obligation scheme is approaching its final decade
The Renewables Obligation (RO) scheme was launched in 2002 to support the development of large-scale renewable energy assets in the UK and will issue its final certificates in 2037. Accredited stations earn a significant additional income stream by selling RO certificates (ROCs), alongside electricity revenues. When this support ends, asset profitability becomes more exposed to merchant power prices and operating costs.
2027 will see the first major wave of stations rolling off the scheme, reducing ROC supply. At the same time, DESNZ is considering the transition to a Fixed Price Certificate model1 with a centralised counterparty to support price and revenue certainty as the market shrinks. A further consultation is expected later this year2, leaving the final design, implementation timetable, and the outlook for ROC prices and subsidy income uncertain.
Using the RO exit timeline to screen opportunities
Figure 1 shows the timeline of onshore wind and solar PV assets exiting RO support, with station capacity grouped by exit year. The support period typically lasts 20 years. If a station’s effective accreditation date is in 2013, it would receive its final ROCs in 2033 (see Methodology for details on estimating the expiry year).
Stations accredited before 26 June 2008 remain eligible for ROCs until 2027, creating the initial expiry spike.
An initial wave of 2.6GW of onshore wind capacity will roll off RO support from 2027. This represents nearly 130 assets, most of which were commissioned in the late 1990s and early to mid-2000s and could offer opportunities to investors specialising in repowering and merchant operation. Another pool of targets could form with the second wave of RO expiries in 2033, totalling 2GW across 140 assets, and including solar PV. Although solar accounts for only 22% of this capacity, it still translates into 70 assets because the average solar project in this cohort is 70% smaller than the average onshore wind project. The later expiry dates for these assets provide investors several years of remaining ROC income, during which they can optimise operations, assess life extension or redevelopment options, and prepare for the merchant tail.
How can investors identify the most attractive opportunities across more than 300 assets?
Lower ROC dependence may point to stronger merchant tail assets
A useful starting point for identifying suitable assets with upside is to assess their dependence on ROC income. Figure 2 shows the estimated ROC income as a share of total turnover for some 750 assets. Across this sample the median share was 41% for onshore wind and 49% for solar PV in 2024. Pyde Drove offers an illustration. The 7MW solar farm located in Somerset reported a 2024 turnover of £1.6 million. Some £790,000 was earned by selling ROCs, making its share over total turnover 49% (see Methodology notes for details).
Assets at the far right of Figure 2 are less reliant on ROC income and could be better positioned for the merchant tail. However, viability will still depend on whether electricity sales are sufficient to cover routine operating costs, major maintenance or component replacement, and any remaining financing obligations.
What else do investors need to consider when prioritising acquisition opportunities?
Three investment theses through the post-ROC transition
2027 could be a watershed for investors interested in the ageing UK onshore wind and solar PV fleet. A shrinking ROC market and uncertainty over future market design could undermine existing revenue assumptions and asset valuations, giving an edge to investors able to identify opportunities using asset-level data across a wide share of the market. This analysis offers an initial glimpse of why this asset base hides commercial potential, where opportunities are most likely to emerge, and how investors might access them. Table 1 sets out three investment theses: resilient merchant tail, repowering play and energy hub optionality.
Resilient merchant tail
Assets capable of remaining cash-generative after ROC support ends. The 2027 wave offers immediate opportunity, covering 2.6GW across nearly 130 older onshore assets. Lower dependence on ROC income is a useful starting point for screening stronger merchant candidates.
Can electricity sales cover the asset’s post-ROC cost base?
Lower revenues post-ROC must cover operating costs that may rise as warranties and service agreements expire and ageing equipment becomes more difficult or costly to maintain. Location and connection type are also relevant, as network charges or embedded export payments can tip the scales on project viability.
Repowering play
Acquire ageing assets where the site’s renewable resource, land rights, access and grid connection may be more valuable than the existing equipment. Many assets in the 2027 wave may be strong candidates for a larger, CfD supported project.
Can the existing site support a viable repowering scheme?
Planning precedent, land and lease rights, available grid capacity and site-access constraints determine the viability and scale of repowering a site can support. A CfD can then strengthen project economics and improve bankability.
Energy hub optionality
Acquire sites where the grid connection and land can support storage, new generation or private-wire supply. The 2033 wave may be attractive because both wind and solar assets retain several years of ROC income during which additional options are assessed and progressed.
Can the added technologies and revenue streams be developed into a viable energy hub project?
This is the most complex of the three investment theses because adding technologies such as battery storage introduces new revenue models and increases overall system complexity. Land availability, site access, planning, grid rights and route-to-market must then align to support a viable business case.
Further analysis and data access
These three investment theses provide a framework for identifying potential opportunities, with criteria aligned to realise a particular investment mandate. Building on this, a broader screening across operational, financial and subsidy support data, combined with ownership analysis to identify likely sellers, can help develop an initial shortlist of credible targets.
Mankappian’s data and research cover both operational and development stage assets to support investors, developers, and advisers with an interest in this market segment. Tailored analysis and access to the underlying data are available for screening and assessing acquisition targets across the UK onshore wind and solar PV market.
The main data sources for the analysis are Ofgem’s Renewable Electricity Register (report as of 11 May 2026) and filings from Companies House. The data covers the following assets:
- Wind onshore and solar PV assets with a minimum 3MW of declared net capacity; and
- Assets with Renewables Obligation accreditation and receiving ROCs in 2024/25.
These criteria result in 1,201 assets, totalling 17.4GW of capacity. In this sample, 755 assets have revenue data taken from annual account filings (FY2024) from Companies House. For every station the final year of RO support is estimated by adding 20 years from its date of accreditation or until 31 March 2037, whichever comes first. Except for stations accredited before 26 June 2008 – these have an end year of 2027.
The ROC income is calculated based on the number of ROCs issued (redeemed or issued) during the 2024 financial year and the ROC buy-out price (see Table 2). The turnover figure is taken from a project’s 2024 financial year Companies House filing. The resulting ROC income share over total turnover is a conservative estimate because projects may earn additional income from ROC recycle value and Renewable Energy Guarantees of Origin – both mechanisms are excluded from the analysis.
1. DESNZ, Introducing Fixed Price Certificates into Renewables Obligation schemes: call for evidence, 31 July 2023
2. Ofgem, Renewables Obligation Annual Report, Scheme Year 23 (1 April 2024 to 31 March 2025), 30 March 2026
This report forms part of an ongoing asset-level analysis of the UK solar PV, and onshore and offshore wind market, combining project, subsidy, generation, financial and grid data to support investment screening, analysis, and decision-making. For further information, access to data, or discussion of specific assets and portfolios, please contact: