CP2030 has changed curtailment risk by reshaping how projects are treated within the LIFO stack, altering which technologies connect, in what order, and how system flows are managed across the GB network. Find out more about what this could mean for your project and how Blake Clough can help navigate Clean Power 2030 changes.
CP2030 Has Changed Curtailment Risk
With the finer details of grid reforms now known and taking place, many projects will unfortunately receive Gate 1 offers and hence not connect to the system. As part of this, Blake Clough has supported developers on Clean Power 2030 (CP2030) by creating algorithms to replicate NESO’s queue re-ordering process.
Modelling the CP2030 Reformed Connections Queue
These algorithms match grid projects to their planning status, letting developers know the chances of getting a good Gate 2 offer. The core of this work has involved estimating the likely order of the reformed connections queue. High-quality bespoke planning and grid connection data are used, applying specialised algorithms developed to account for complexities around protections, rebalancing, and project attrition. In some instances, this proactive approach has saved projects which would otherwise have been ineligible for Gate 2 offers. Additionally, risks around the Gate 2 process have consistently been identified and quantified, ensuring developers get the best possible outcome from these reforms.
CP2030 Impact on Curtailment
The direct impact of CP2030 will be to remove Gate 1 projects from all relevant curtailment LIFO stacks.
With this comes significant changes in the types of projects connecting to the system; and as a result substantial changes in system flows. As different technology types are expected to be asymmetrically affected by the reforms, this inevitably translates into notable shifts in expected curtailment levels, particularly for overload-driven curtailment schemes. It is not just a question of how much capacity connects, but which technologies connect and in what sequence.
Uncompensated curtailment actions in Great Britain (GB) are generally undertaken in Last-In, First-Out (LIFO) order, meaning that projects which were last to enter the network operator’s priority stack (i.e., the “LIFO stack”) will be the first to experience curtailment when required.
These reforms are urgently needed as the connection queue is significantly oversubscribed, with over 750GW of projects attempting to connect, vastly exceeding the approximately 220GW required by 2030 and the 380GW projected for 2050. The CP2030 reforms aim to directly address this queue backlog, introducing clearer procedures that enable more accurate modelling of project viability and network loading impacts.
These anticipated changes will influence all types of overload-based curtailment schemes across GB. This includes
- Load Management Schemes (LMS), the operating logic behind Overload Protection, Operational Intertripping Schemes, and Restricted Available Access),
- Active Network Management (ANM),
- Technical Limits,
- Thermal Management Schemes,
- Accelerated Storage Schemes,
- Merit Order Management (MOM), the curtailment scheme currently used by Electricity North West Limited (ENWL),
- Appendix D overload-dependent restrictions, and
- Other less common schemes sharing similar underlying principles or simply differing in naming conventions, such as Generation Export Management Scheme (GEMS).
These schemes are all fundamentally dependent on network flows, and therefore are highly sensitive to changes in the connections queue.
Improved Precision from CP2030 Rules
Across GB, the prescribed zonal capacity thresholds within CP2030 mostly align with NESO’s Future Energy Scenarios (FES) predictions. However, the Strategic Spatial Energy Plan (SSEP) arriving in 2026 is anticipated to adjust the zonal capacity thresholds upwards in some cases, but crucially will not reduce queue sizes or remove projects. Previously, significant uncertainty around connections resulted in a wide gap between worst- and best-case scenarios (e.g., the 5th and 95th percentiles). However, the detailed documentation and guidance provided by NESO around CP2030 have now considerably improved the certainty of our models. Specifically, NESO’s CP2030 documentation clearly identifies projects likely to receive Gate 1 offers, effectively removing them from the connections queue. This significantly improves our ability to remove uncertainty while generally obtaining lower curtailment estimates.
While the clarity and CP2030-driven attrition typically result in reduced curtailment estimates, asymmetrical impacts across different technology types can lead to unexpected outcomes. For example, solar projects may see increased curtailment due to a disproportionately higher dropout rate of battery energy storage system (BESS) projects ahead in the queue. The reason is simple: BESS projects typically import energy around midday, freeing network headroom for solar generation. The dropout of these BESS projects removes this additional headroom, leaving more solar projects competing for limited midday network capacity and thus increasing solar curtailment. Conversely, BESS projects typically fare better due to fewer competing projects ahead of them. Only in cases where BESS are relying heavily on solar projects ahead of them (which subsequently drop out) could they experience reduced import headroom during solar peaks; however, this scenario is much rarer in our recent experience.
Asymmetric Impacts on the Various Technologies
For wind projects, the impacts of CP2030 are often a mix of the two due to their ability to operate at all hours of the day, unlike BESS which operates in 1–2 peaks/troughs and solar which only operates around noon. While wind projects may be less affected by BESS attrition, they are still subject to similar dynamics depending on the technology mix in their specific zones. For example, in parts of Scotland where wind dominates, reductions in BESS could still result in increased constraints during high wind periods. Conversely, in areas where generation is reduced under CP2030, wind projects may benefit from enhanced export opportunities. Looking forward to beyond 2030, we expect wholesale electricity prices to be even more correlated with power generated by wind farms.
Blake Clough has an extensive array of analytical tools designed to accurately and realistically capture these nuances. For example, planning data indicates that older BESS projects in the queue often feature shorter-duration (around one-hour) storage capabilities, reducing their curtailment impacts on other projects. A one-hour BESS will only absorb excess generation for a limited period (or compete with generation for a limited period during peak times), whereas a two- or four-hour system can contribute more meaningfully to system balancing throughout the day. Modelling must reflect these real-world parameters to avoid under- or overstating curtailment benefits.
Gas turbines, for example, sometimes operate for only a limited number of hours per year due to being reserved for emergency use. This information facilitates more realistic and less conservative curtailment modelling. Furthermore, the impact of contingencies, Future Energy Scenarios, and bespoke client sensitivities can also be analysed, ensuring assessments remain flexible and tailored to client needs.
Loss of Availability from Outages and Abnormal Running Arrangements
It is also important to note that, despite overload-driven schemes being the primary focus, Blake Clough always includes analysis of network outage conditions in their assessments. In some of the more extreme cases analysed, outage conditions can increase expected curtailment by over 10% if the local network is operated or configured non-ideally (such as disconnections following demand transfers between GSPs, or single-circuit security for a large section of a Distribution network). Although these cases with an extremely high anticipated loss of availability are fortunately rare for projects with overload-based constraints, careful analysis is crucial to quantify these risks accurately. In some cases, outage-driven constraints may present a large unavailability risk where overload curtailment is expected to be minimal.
Curtailment Analysis for Financeability Assessments
These effects are not just technical details, as they have material commercial implications. Curtailment analysis remains absolutely essential for project viability. The majority of GB connections now face some level of operational restriction, significantly influencing potential revenue. With Distribution Network Operators (DNOs) frequently employing overly conservative curtailment assumptions (though this general rule is not always true and we have many times found the inverse of this), and NESO not providing any curtailment assessments at all, independent expert analysis is critical. Such analysis accurately predicts project curtailment over the entire lifecycle, typically spanning decades. This accuracy provides developers with confidence in proceeding with projects, provides investors and buyers with certainty regarding investment potential, and ensures realistic project valuation for future sales.
It is also increasingly common for project investors or acquirers to request third-party validation of curtailment assumptions used in revenue modelling. This further underlines the importance of having defensible, clearly evidenced curtailment estimates grounded in an understanding of both wider CP2030 reforms and the operation of the local curtailment scheme. With grid reforms reshaping project queues and operating conditions, historic rule-of-thumb assumptions will no longer be reliable.
CP2030 Has Changed Curtailment Risk – Summary
- Grid reforms will substantially impact network loads, directly affecting project curtailments.
- Precise quantification of these impacts is achievable, leveraging our detailed CP2030 analytical expertise and feeding this into curtailment studies.
- While most scenarios indicate curtailment improvements, cases such as solar projects with significant dropout of BESS capacity ahead in the LIFO stack can see adverse impacts.
- Curtailment risk is highly location- and technology-specific, and must be understood in detail to support viable project development.
- Blake Clough combines extensive experience in CP2030 analysis and curtailment assessments to deliver accurate, actionable insights tailored to specific portfolios.
At Blake Clough, our team remains ready to guide you through these upcoming changes. Whether your portfolio consists of one project or one hundred, feel free to reach out. We are always available to provide honest, practical advice on the impact these reforms may have on your projects and advise on whether a detailed assessment may be beneficial.
