Shane Oxer. Campaigner for fairer and affordable energy.
“A megawatt that cannot be delivered is not energy security. It is an accounting fiction.”
In January 2026, a single statistic exposed the structural failure at the heart of Britain’s energy policy. Scotland’s largest offshore wind farm, Seagreen a 1 GW flagship project off the Angus coast , wasted approximately seventy-seven per cent of the electricity it produced over the course of a year because the transmission system could not carry the power to where it was needed.¹ Instead of supplying homes and businesses, the turbines were instructed by the system operator to stop producing electricity, and the plant was compensated for doing so under the National Energy System Operator’s constraint regime.¹ ²
These so-called constraint payments, designed to ensure grid stability when local energy flows exceed network capacity, are now a major cost on consumer bills. According to the latest grid data, constraint actions by NESO have become a routine part of system balancing, with thermal constraint volumes , often caused by insufficient transmission capacity for abundant generation , increasing by eighty-one per cent year-on-year.³ Meanwhile, independent analysis has shown that consumers bore direct curtailment costs of nearly £400 million in 2024 for discarded wind alone, with total curtailment costs already nearing the billion-pound mark.⁴ ⁵
For years, ministers have spoken in terms of “installed capacity” and “projects approved”, as if these headline figures were synonymous with deliverable power. They are not. A generating asset that exists only on paper, or that is routinely prevented from exporting electricity by grid bottlenecks, does not contribute to security of supply in any meaningful sense. It contributes only to accounting optics. A megawatt that cannot be delivered is not energy security. It is an accounting fiction.
Seagreen is not an isolated embarrassment. It is the logical and predictable outcome of the doctrine that has dominated British energy planning: build generation capacity first and assume the grid will catch up later. Under this approach, generation is consented and constructed long before the transmission system, substations, transformers, converter stations and associated stability equipment required to support it are ready. The assumption is that grid upgrades can simply be fast-tracked afterwards. In practice, this has produced a growing fleet of assets that are fully built, formally “connected”, yet routinely constrained , often because the network lacks the capacity to carry their output at peak times.
The cost consequences of this strategy are now visible in the official numbers. NESO’s own data portal shows that constraint actions have become a substantial element of system operation , encompassing millions of half-hour balancing instructions globally across months and years.³ Although not all constraint costs are directly paid to renewables, the sheer scale of the interventions demonstrates that the grid’s ability to cope with energy flows is degrading relative to the pace of new generation being added. Independent commentators have warned that, without significant reinforcement of transmission capacity, constraint costs could reach multi-billion-pound levels by 2030 even under current forecasts of network expansion.⁴
Equally revealing is the Government’s own planning data. The UK’s Clean Power 2030 Action Plan: A new era of clean electricity, published by the Department for Energy Security and Net Zero, sets out its vision for decarbonising the electricity system by 2030, and includes extensive modelling on investment, consumer benefits, and grid impacts , implicitly recognising that without sufficient network upgrades, generation alone cannot deliver secure and affordable power.⁶ NESO’s Clean Power 2030 Implementation Plan further details the operational challenges and proposed actions to support delivery of the government’s clean power objectives, including stakeholder engagement and system enhancements.⁷
A deeper problem underlies these policy documents, however: the political assumption that grid infrastructure can be delivered on the timescales set by ministerial targets. The real world of electrical engineering tells a different story. The United Kingdom , like most advanced economies , is now contending with severe manufacturing bottlenecks in essential high-voltage equipment. Super Grid Transformers, high-voltage direct current (HVDC) converter stations, protection systems, and complex switchgear are all subject to long lead times due to global demand, limited specialised factories, and competing projects across Europe, North America and Asia.⁸ These industrial constraints mean that, even when transmission reinforcements are consented and funded, the physical delivery of network infrastructure can lag by many years, further entrenching the mismatch between theoretical capacity and practical usability.
When this problem is raised by policymakers, the response is often to point to storage technologies or “system flexibility” measures. But short-duration battery storage, pumped hydro or hydrogen facilities cannot move bulk power across a constrained network; they cannot alleviate seasonal mismatch; and they cannot replace the firm power and inertia that a heavily decarbonised grid with high levels of variable generation still requires. These technologies have roles to play, but they do not address the fundamental bottleneck: a lack of transport capacity from energy-rich regions to centres of demand.
There is also a national security dimension to this disconnect. The UK Government’s energy resilience planning recognises that a more complex, electronically mediated grid , reliant on remote, weather-dependent generation and sophisticated balancing , is exposed to cascading failures and prolonged outages if critical infrastructure cannot be quickly repaired or rerouted.⁹ A grid that cannot reliably deliver power from where it is generated to where it is needed is not merely costly; it is strategically fragile. The more the system depends on long specialist supply chains for critical equipment, the harder it becomes to recover quickly from major faults.
The consequences of these structural flaws are now becoming evident in regional settings. Across Yorkshire and the Humber , including areas such as the Drax corridor, West Melton, Thorpe Marsh and Brinsworth , communities are being asked to host large solar developments, battery storage facilities and new substations for projects that, according to grid operator queue data, will face significant constraints on export capacity for many years.¹⁰ This replicates offshore phenomena onshore: projects that have been consented and built, but whose ability to contribute to usable, deliverable power is compromised by network limitations.
This situation exposes a deeper inversion in the way the British energy system is being constructed. Within any rational engineering programme, the sequence of development would be clear: the grid and its stability services would come first; dispatchable, synchronous generation would be secured to anchor the system; and only then would large volumes of variable generation be integrated. Instead, successive governments have prioritised the rapid expansion of remote, intermittent generation while treating grid infrastructure and system stability as secondary concerns to be reconciled later.
The political presentation of this strategy relies on a simple accounting trick. When ministers claim that they have “approved enough clean power to supply millions of homes”, what is being counted is nameplate capacity and consented projects , not deliverable energy. The question that is never answered honestly is how much of that capacity can actually be used in practice, given existing and projected grid constraints. Until this question is confronted directly, official figures remain notional and fundamentally misleading.
To correct course, Britain must stop counting undeliverable capacity as if it were real, and must stop approving large new projects in constrained zones without first ensuring that the necessary network enhancements can be delivered in a timely manner. The country must adopt a genuine grid-first approach and re-establish the role of firm, synchronous generation in providing a stable backbone for the system. Without such changes, Britain will continue to pour money into infrastructure that looks impressive in policy documents but performs poorly in reality.
Seagreen should be understood not as an aberration but as a preview of the future. Unless the sequencing of energy strategy is fundamentally rethought, the UK will build more capacity that cannot be used, incur ever greater costs, and risk a less secure and more fragile energy system.
A megawatt that cannot be delivered is not energy security. It is an accounting fiction.
Footnotes.
1. Jonathan Leake, “Scotland’s biggest offshore wind farm wasting three quarters of energy”, The Telegraph, 7 January 2026, https://www.telegraph.co.uk/business/2026/01/07/scotlands-biggest-offshore-wind-farm-wasting-three-quarters-energy/.
2. “An overview of constraint payments”, RenewableUK blog, 15 April 2025 — covering NESO data on constraint payments and share across generators, https://www.renewableuk.com/news-and-resources/blog/an-overview-of-constraint-payments/.
3. Constraint Breakdown Costs and Volume dataset, National Energy System Operator (NESO) data portal, showing constraint costs and actions for 2024–25, https://www.neso.energy/data-portal/constraint-breakdown.
4. Britain wastes enough wind generation to power 1 million homes, Carbon Tracker, 15 June 2023 — analysis on curtailment and system costs, https://carbontracker.org/britain-wastes-enough-wind-generation-to-power-1-million-homes/.
5. Field Energy analysis, “£920 million annual cost of curtailment…”, Field Energy, 7 April 2024 — on historical and projected curtailment costs, https://field.energy/views/field-analysis-920-million-annual-cost-of-curtailment-could-be-cut-80-by-using-existing-technologies-like
6. Clean Power 2030 Action Plan: A new era of clean electricity, UK Government, 15 April 2025, https://www.gov.uk/government/publications/clean-power-2030-action-plan/clean-power-2030-action-plan-a-new-era-of-clean-electricity-main-report.
7. Clean Power 2030 Implementation Plan, NESO, 17 June 2025 — detailing operational plans supporting government action plan, https://www.neso.energy/publications/clean-power-2030.
8. National Grid ESO Beyond 2030 report — recommendations for network upgrades through the 2030s, including investment needs, https://www.neso.energy/publications/beyond-2030.
9. Power struggle: Delivering Great Britain’s electricity grid (House of Lords Industry and Regulators Committee report), June 2025 — on system challenges and risks, https://publications.parliament.uk/pa/ld5901/ldselect/ldindreg/132/132.pdf.
10. National Grid / Northern Powergrid connection queue and reinforcement data (public queue lists), showing constrained regions such as Yorkshire (grid operator sites typically list queue and constraint information; specific substations and constraint zones are identifiable in these data portals). Also see Eastern Green Links HVDC project details indicating needed reinforcement on the east-west spine, https://en.wikipedia.org/wiki/Eastern_Green_Links.
SAY NO TO THE DESTRUCTION OF OUR LAND 
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