How every number
is worked out

What is original here, and what is not

None of the underlying data is ours and none of it is secret. Elexon publishes every balancing action, DESNZ publishes the planning database, NESO publishes the constraint costs and the connection queue, ONS publishes the boundaries and the census. Anyone can download all of it. If you already work in energy, you have seen these sources.

What did not exist before, as far as we can tell, is the join:

• The constituency view. Elexon reports by balancing-mechanism unit, REPD by site with coordinates, NESO nationally. Nobody publishes any of it by Westminster seat. Putting money and megawatts into the geography that MPs, councillors and local papers actually work in required the hand-maintained BMU→site mapping (published, with confidence grades) and a point-in-polygon geocode of every site.
• The reason join. "Approved and not built" is in REPD; why it is not built is not. Joining the planning record to connection queues and appeal status, and reducing that to one plain sentence per project with a named decision-maker, is the part that turns a number into something a person can act on.
• The time series and the cleaning. A year of settlement-quality switch-off costs per unit, reconciled against NESO's own published volumes, with the sign conventions and the unit traps (their volumes column is MW per half-hour, not MWh) handled and tested.
• The translation. One comparator, used everywhere, for every pound; homes-equivalent stated as annual energy rather than instantaneous capacity; caveats at the point of use rather than in a footnote.

So: the facts are public, the arrangement is the work. If you think a join is wrong, the mapping file, the reconciliation and every seat's JSON are published so you can check it rather than take our word for it. Corrections are welcome and get credited.

Number 1 — £ paid to switch off wind farms (the industry word is "curtailment")

Source: the Elexon settlement bid stack (/balancing/settlement/stack/all/bid), which gives the accepted bid volume (MWh) and original bid price (£/MWh) per balancing-mechanism unit (BMU) per half-hour, as derived by Elexon settlement. We keep turn-down (bid) actions on wind BMUs only. Cost = volume × price: a wind farm bidding a negative price is paid to reduce output, so the product is a positive cost to the system.

Attribution: BMUs are matched to sites in the government's Renewable Energy Planning Database (REPD) by a hand-reviewed mapping file with a confidence grade per row (candidate suggestions are published too). One site can span several BMUs (Viking has four) and one BMU can span several REPD entries (phased builds — the share column splits them). Sites are placed in constituencies by point-in-polygon against the ONS July-2024 boundaries.

What is deliberately left out of seat totals: offshore wind (£210m in the window) is reported nationally, never attributed to a coastal seat. Money on BMUs we could not confidently map — £21m, 5.2% of the total — sits in a published unattributed bucket rather than being guessed into a seat. Corrections to the mapping are welcome.

Window: 1 August 2025 to 31 July 2026. Elexon revises settlement data for months; the weekly rebuild re-pulls the trailing 14 days.

Reconciliation against NESO

NESO publishes no wind-only curtailment cost in any machine-readable dataset, so the primary check is volumes, against NESO's per-BMU "Wind BOA Volumes" dataset, plus the GWh figures NESO quotes in its Monthly Balancing Cost Report. One unit note: NESO's BOA_Volume column is MW per half-hour settlement period, so energy = value × 0.5 — uncorrected it reads exactly double.

Spot checks against the report itself: May 2026 — ours 591 GWh vs NESO's quoted 591; June 2026 — ours 707 vs quoted 709. Per-BMU, 51 units above 20 GWh were compared; 1 fall outside ±2% and are listed in reconciliation.json. The build fails if any complete month disagrees by more than 2%.

Number 2 — consented but not built

Source: REPD quarterly extract (DESNZ), July 2026 edition. "Stuck" means development status Awaiting Construction or Under Construction with consent granted more than 24 months before the extract date (a 12-month cut is also computed and published). Consent date is the latest of planning permission granted, appeal granted, or Secretary of State granted. Refusals, withdrawals and the median months from application to decision use a five-year window.

What counts as "clean power" here: onshore and offshore wind, solar, hydro, tidal and wave — the generating technologies in the planning database. Battery storage is counted separately throughout this site, because a battery does not generate electricity; it moves it in time. Every seat page and briefing names the technology mix rather than leaving "clean power" to the imagination.

A note on "enough for X homes". Electricity does not flow from a particular project to particular houses. Everything generated goes into the national grid, and every home draws from that shared pool — so a wind farm in Caithness is not "powering" Caithness, and a solar farm outside a town does not supply that town. The homes figure is a way of sizing an amount of electricity in units people recognise: it is the annual output of the project divided by what a typical household uses in a year. It is a measure of quantity, not of who receives it.

Homes-equivalent = MW × technology load factor (DUKES 2026, five-year average) × 8,760 h ÷ 2,500 kWh (Ofgem's typical household electricity consumption, cut from 2,700 to 2,500 kWh in July 2026 — a change that quietly moved every homes-equivalent claim on the internet). REPD only includes projects above 150 kW (1 MW before 2021), understating small-scale totals. Statuses lag: where a "stuck" site demonstrably has a generating BMU we say so in the mapping notes.

Number 3 — the constraint bill per household

Source: NESO's Monthly Balancing Services Summary, constraints definition (England & Wales + Cheviot + Scotland constraint actions, constraint ancillary services, RoCoF/inertia, constrained sterilised headroom), cross-filled from the daily Constraint Breakdown dataset for months MBSS has not yet covered. Rolling 12 months: £2.5bn ÷ 27,292,462 GB households (Census 2021/22 via ONS, NRS and NISRA) = £92 per household. It is a national figure — the same for every GB seat; only the seat total varies with household count. Northern Ireland is in the all-Ireland SEM and is shown as not applicable, not as zero.

Relationship between the numbers: paying wind farms to switch off (£409m) is 16% of the whole constraint bill. The rest is mostly the mirror image — paying generators south of the bottleneck to turn up — plus voltage and stability actions. Number 1 is what was paid to wind here; Number 3 is the whole system bill.

Batteries

Battery figures come from the same planning database (REPD), Technology Type = Battery, bucketed as operating / being built / approved-not-built / refused (five-year window) / in planning. REPD carries no MWh (duration) column, so we never claim hours of storage. REPD's operating figure (5.0 GW) lags reality — industry trackers put the fleet at about 7.2 GW — so treat the operating number as a floor; the approved and refused numbers are planning records and are not affected by that lag.

The B6 bottleneck figures

The "wires are full" numbers on the front page come from NESO's day-ahead constraint flows and limits dataset for the SCOTEX (B6, Scotland–England) boundary: the flow is NESO's day-ahead modelled unconstrained flow — what wanted to cross — not metered outturn, because NESO publishes no outturn boundary flows. "Full" means wanted flow at or above the boundary limit.

Planning statuses: what we claim, and how to check it

Every planning status on this site — approved, refused, under construction, awaiting a decision — comes from one place: the Renewable Energy Planning Database (REPD), the quarterly extract published by the Department for Energy Security and Net Zero. We do not visit council websites or interpret committee papers. That has three consequences a careful reader should know:

• We report status and date, never reasons. REPD records that an application was refused and when. It does not record why. So this site says "Refused by Dorset Council in 2025" and stops there. If you see a reason for refusal quoted anywhere on this site, it is a bug — please tell us.
• Every project carries its planning application reference, on the seat page and in the briefing, so you can go to the primary record. For the 150 MW Buckland Battery Storage in South Dorset, for instance, the reference is P/FUL/2024/04993 and the applicant is REWE 5 Limited — that gets you the decision notice, the officer's report and the reasons, none of which we are in a position to summarise for you. Where we have been able to find the council's record ourselves, the reference is a link: 0 of the 3,353 projects we name link straight through. We fetched each of those links once and publish only the ones that answered, so a reference shown as plain text means we could not find the record — never that it does not exist.
• REPD is a secondary source and can lag. It is compiled from council decisions and developer returns, and the extract we use is dated July 2026. A decision made or appealed after that date will not appear, and occasional records are known to be incomplete or out of date. Where our reading of REPD conflicts with a council's own register, the council's register is right and we are wrong — send us the reference and we will correct it.

If we cannot check a claim, we do not publish it. Two rules follow from that:

• No reference, no claim. We only name a specific project and assert a status about it when the planning database gives us the application reference that lets you look it up. 9 projects across all 650 constituencies are withheld on this rule — real enough to sit in the national totals as part of the dataset, but not something we will put a name to without a route to the primary record.
• Contradicted records are deleted, not footnoted. Where we have checked a record against the authority's own register and it does not hold up — or we tried and could not confirm it — the record goes in a public exclusions file and is dropped at ingest, so it reaches no page, no total and no published file. The file records what was checked and when. It currently holds 7 records.

Where the council records come from. There is no national planning register — every council keeps its own — so both the refusal check and the reference links go through PlanIt, a free service that collects council registers and publishes them in a machine-readable form. It is an aggregator, not the source: each record it returns carries a link back to the deciding council's own register, and that is the one that settles any disagreement with us.

One further caution about searching for these projects yourself: battery and solar applications are often named after a farm or field rather than the nearest town, and several similar schemes can sit within a few miles of each other. A refusal you find in the news is not necessarily the refusal in our table. The application reference is the only reliable way to tell two neighbouring schemes apart.

Why a project is stuck, and what building it would do

Each project in a constituency briefing gets one reason, assigned by an ordered rule set — refused, then under appeal, then awaiting a planning decision past 12 months, then connections-reform outcome, then grid connection date, then under construction, then approved with no recorded progress, then in planning. First match wins; all matches are kept in the seat JSON. Where the public record does not say, the reason is "no public record of what is holding this up" — we never guess. "Who can move it" follows from the reason: the named planning authority, the Planning Inspectorate, NESO and the network owner, or the developer.

How we decide who can move a project

Each project's "who can move it" follows mechanically from the reason it is stuck. We do not judge who is at fault; we name the organisation that holds the next decision:

Two honest limits. First, "the developer and the network company" is the weakest of these: it means only that no public record shows anyone else holding the project up, which is not the same as knowing why it has not been built — the reason may be a supply chain, a landowner, or a decision never to proceed. Second, where a council is named, we name the authority and never an individual officer or councillor; the decision is the council's, and the reasons for it are in its own register rather than here.

Why "nothing has happened since" is the commonest answer. It applies to a little over half the projects on this site, and that is a fact about the public record rather than about the projects. The planning database tracks a project through the planning system and then stops: it records the date permission was granted, and the date construction started, and nothing in between. There is no public field for ordering a transformer, signing a connection agreement, reaching financial close, or quietly shelving a scheme. So for a project that holds permission and has not started work, the honest statement is that no public record shows anyone else holding it up — not that we know it is stalled, and not that we know why. Where a grid connection date exists in NESO's register we say so, because that is the one post-permission milestone anybody publishes. The rest of the consent stack — land rights, finance, a buyer for the power — is set out under every approval a project needs, and most of it is private.

Every approval a project needs

Planning permission is one gate of several, and it is the one everybody reports on because it is the one that holds a public hearing. A project can hold it and still be years from being built. This is the full stack, who grants each part, and — the point of the table — whether a member of the public can check it at all. Researched and every source fetched on 25 August 2026.

Two rows have no national register to link, because there is no such thing: planning permission and the environmental assessment decision sit on each council's own register, one register per council. Where a project on this site holds a reference we have checked against that register, the reference on its seat page links straight to the record. Every URL in the table was last fetched, and answered, on 26 August 2026; the machine-readable version is consents.json.

What a project does not need

Three approvals get assumed onto lists like this one and do not normally apply. Showing them as missing would invent a problem a project does not have, so we name them here instead.

• Hazardous substances consent. The Health and Safety Executive's position is that lithium-ion batteries are articles rather than substances, so a normal battery site does not need this consent and is not covered by the major-hazard rules. It bites only where a site stores something else in bulk, such as diesel for backup generators. Source. Some published safety research argues large lithium-ion sites should be caught by the rules on substances generated when a process goes wrong. That is an open argument, not the current position.
• Fire and rescue service sign-off. The fire service is not a statutory consultee on battery storage planning applications. Its guidance says so in terms. Many developers consult it anyway and publish an outline safety plan, but no approval is being given and none can be withheld. Source. A Battery Energy Storage Systems (Fire Safety) Bill would make fire authorities statutory consultees. It is not law.
• Building regulations approval. Battery sites are not dealt with through building regulations, except for ancillary buildings such as site offices. There is no public record of building control decisions at project level in any case. Source.
• Environmental permit. Grid-scale batteries are not currently covered by environmental permitting. The government consulted on bringing them in during August 2025 and has not published a response. Source. If the consultation lands, this becomes a real approval with a public register.

Connection dates come from NESO's Transmission Entry Capacity register and its Embedded register — the public queue of projects with agreed connection dates. NESO repeats rows per project stage, so we deduplicate on Project ID, keeping the earliest connection date. The registers carry no postcode or grid reference, so the join to the planning database is by normalised project name plus a capacity check, published as a mapping file with confidence grades and a candidate list. A guard rejects matches that rest only on a shared generic phrase — "Greener Grid Park" appears in many project names and is not evidence that two records are the same project. We would rather miss a match than assert a wrong one, so a project with no confident match simply shows its planning status instead of a connection date.

Connections reform (Gate 2). NESO does not publish project-level reform outcomes: its detailed results are aggregated by zone for commercial-sensitivity reasons. The machine-readable outcome is the Gate column added to the connection registers in November 2025, populated only as agreements are countersigned — so most of the queue is still blank, and a project without a Gate marking has not necessarily failed anything.

Impact estimates come from per-MW factors in a versioned file, each with a source, a date and a status. A sentence only appears when the factor for that technology exists — a missing factor means a missing sentence, never a zero. Three distinctions we keep visible, because they are where this kind of estimate usually goes wrong:

• In force vs proposed. The £5,000/MW/year community benefit rate for onshore wind is current government guidance. The solar and battery rates are from a Scottish Government consultation paper and are not in force; where a seat's figure uses them, the page says so.
• Published vs derived. The VOA publishes no per-MW business rates factor for wind or storage — it values them on a receipts-and-expenditure basis with unpublished models. Our figures are derived from the VOA's own 2026 rating list joined to project capacities, and are described on the page as what comparable sites are rated at, not as an official rate. Solar is the exception: there is a published VOA / Solar Energy UK agreement.
• Workers on site, not job-years. Construction figures are peak concurrent workers, taken from Scottish Government workforce research and consented NSIP environmental statements. Published UK job-year estimates vary by a factor of two to four depending on whether indirect effects are counted, so we do not use them. No credible per-MW construction figure exists for grid-scale batteries, so batteries are left out of that line entirely.

What we cannot see

• Distribution-level curtailment is invisible. Wind farms connected to local networks are curtailed under Active Network Management by network operators; those payments never appear in national balancing data. English and Welsh seats showing "not visible" are not necessarily curtailment-free — the national record simply cannot see them. This means the site understates the true cost.
• Aggregated portfolio BMUs (e.g. supplier units bundling several small farms) cannot be honestly attributed to one site and stay in the unattributed bucket.
• REPD status lag: planning statuses can run a quarter behind reality.

Comparators

Every tangible framing resolves through a versioned comparators file; nothing is hardcoded. Values, sources and as-of dates:

Changelog

• 2026-08-25 — first build: REPD Q2 2026, Elexon settlement stack Aug 2025–Jul 2026, MBSS to Jun 2026 (Jul 2026 provisional from Constraint Breakdown), Census 2021/22 households, comparators verified against primary sources.