The Carbon Ledger: CB7 vs Heavy Industry Reality

In June 2026, Parliament codified the Seventh Carbon Budget (CB7) into law, legally binding the UK to an 87% reduction in greenhouse gas emissions by 2040 and capping the 2038–2042 period at 535 MtCO2e. On paper this is a straight line on a graph. In the North Sea, the Mersey estuary and the industrial belts of Yorkshire and Humberside, it is a construction schedule — one that depends entirely on subsea carbon capture, usage and storage (CCUS) infrastructure that does not yet exist at the scale the budget assumes.

This is the structural conflict underneath CB7: the target is a legislative instrument, but the abatement pathway is a civil engineering programme. Grid decarbonisation and transport electrification can absorb a good deal of the reduction curve through the 2030s. Heavy industry cannot. Cement, lime, iron, ammonia and glass manufacturing produce CO2 as an inherent output of chemical process, not merely as a combustion by-product of the energy used to drive them — and no amount of renewable electricity on the grid changes that stoichiometry.

  • The gap is not political will, it is capacity. CB7 compliance in the industrial sector requires captured-and-stored volumes to rise from near-zero in 2026 to tens of millions of tonnes annually within roughly a decade — a ramp rate with no UK precedent in any comparable infrastructure class.
  • Electrification covers roughly half the UK's territorial emissions inventory at best. The remainder — concentrated in a small number of geographically fixed industrial clusters — is precisely the segment CB7's own advisory modelling flags as “capture-dependent” rather than “substitution-dependent”.
  • The clusters cannot relocate. Teesside, Merseyside, Humberside and South Wales sit where they do because of legacy port access, feedstock logistics and grid connections built up over a century. Abatement has to come to them, via pipeline, not the other way round.

The remainder of this analysis treats CB7 not as a policy headline but as an engineering brief, and asks whether the pipeline network required to hit it can physically be built, financed and connected inside the window the statute allows.

The Chemistry Trap: The Calcination Problem

Heavy industry represents a hard brick wall for the standard decarbonisation toolkit because a large share of its emissions are not fuel emissions at all. The clearest case is cement.

Up to two-thirds of a cement kiln's CO2 output comes from calcination, not combustion — the thermal decomposition of limestone into quicklime:

CaCO3 → CaO + CO2

This reaction is the chemistry, not the energy source, of cement manufacture. Swap the kiln's fuel for green hydrogen, biomass or electricity and the process emissions do not move — the limestone still releases its carbon the moment it is heated past roughly 900°C. You cannot electrify away a decomposition reaction. The only physical interventions available are capturing the CO2 at the stack, substituting a meaningful share of clinker with lower-carbon alternatives, or reducing cement demand outright — and current substitution chemistry (fly ash, slag, calcined clays) closes only part of the gap before performance and standards constraints bite.

The same structural problem recurs, with different chemistry, across the industries CB7 leans on hardest:

  • Iron and steel (integrated route): blast furnace reduction of iron ore relies on carbon monoxide as the reducing agent, generating process CO2 independent of the furnace's heat source. Direct-reduction and electric-arc alternatives sidestep this, but require either green hydrogen supply chains or scrap feedstock at a scale the UK does not currently have.
  • Lime production: essentially the same calcination reaction as cement, deployed across glass, steel flux, water treatment and agriculture — a diffuse emissions source with no single large point of capture.
  • Glass manufacture: high-temperature melting combined with carbonate raw materials produces a hybrid of combustion and process emissions, complicating capture-rate calculations at facilities like those served by HyNet.
  • Ammonia and chemicals: feedstock-derived process emissions from natural gas reforming persist even where the reactor's process heat is decarbonised.

The practical upshot: eliminating fossil fuels from the electricity grid still leaves several million tonnes of unavoidable industrial process CO2 annually that has no destination other than physical capture, compression and subsea pipeline transport to a storage reservoir. CB7's industrial-sector abatement curve is, in effect, a bet on pipeline delivery dates.

Mapping the UK's Subsea Carbon Networks

Two industrial clusters reached Track-1 financial close status ahead of the milestones set out in CB7's supporting delivery plan. Both now carry the weight of a disproportionate share of the UK's near-term industrial abatement target. The table below sets out capacity, storage geology and construction status as of August 2026.

Industrial Cluster Network Primary Operator / Delivery Vehicle Target Storage Reservoir Location Annual Capture Target (Mid-2030s) Current Construction Status (August 2026)
East Coast Cluster — Northern Endurance Partnership (transport & storage) bp / Equinor / TotalEnergies (NEP joint venture) Endurance saline aquifer, Southern North Sea (offshore Teesside) Network cap of up to 27 MtCO2/yr by mid-2030s Offshore pipeline and injection well construction under way; first injection targeted ahead of full-network completion
East Coast Cluster — Net Zero Teesside Power (anchor emitter) bp / Equinor (Net Zero Teesside Power JV) Piped to Endurance via NEP trunkline Up to c. 2 MtCO2/yr (gas-fired power CCS) Power station construction advanced; capture train commissioning phased against pipeline readiness
East Coast Cluster — H2Teesside / industrial capture tie-ins Multiple industrial emitters (Teesside/Humberside corridor) Piped to Endurance via NEP trunkline Contributes to overall 27 MtCO2/yr network cap Individual emitter connection agreements sequenced behind trunkline capacity availability
HyNet North West — Liverpool Bay CCS (transport & storage) Eni (Liverpool Bay CCS Ltd) Douglas/Hamilton depleted gas fields, Liverpool Bay, Irish Sea Phase 1 target of up to c. 10 MtCO2/yr, rising toward c. 30 MtCO2/yr long-term Repurposing of existing platforms and pipeline infrastructure under way; phased injection ramp-up in progress
HyNet North West — anchor industrial emitters (cement, glass, energy-from-waste, refining) Multiple emitters across Cheshire, Merseyside and North Wales Piped to Liverpool Bay via onshore/offshore HyNet trunkline Contributes to Phase 1 network target Onshore pipeline corridor construction and individual capture-plant retrofits sequenced by connection date

Reading the table correctly matters more than reading it optimistically. The headline “annual capture target” figures are network-level ceilings for the mid-2030s, not throughput achieved today — actual injected volumes in 2026 are a small fraction of nameplate capacity at both clusters, because construction status shows trunk infrastructure and storage wells still being commissioned ahead of the individual emitter tie-ins that generate the tonnage.

Three infrastructure limitations sit underneath every row of that table:

  • Injection well count is the binding constraint, not pipeline diameter. Reservoir engineering limits how fast CO2 can be safely injected per well; hitting nameplate capacity requires multiple wells drilled and commissioned in parallel, not simply a wider pipe onshore.
  • Depleted gas fields (HyNet) and saline aquifers (East Coast Cluster) behave differently under injection. Depleted fields have well-characterised geology from decades of hydrocarbon production; saline aquifers carry more subsurface uncertainty, requiring more conservative early injection rates and monitoring.
  • Anchor emitter connections are sequenced, not parallel. Each factory-side capture plant needs its own tie-in point, monitoring metering and offtake agreement — meaning the trunk pipeline reaching an industrial estate is necessary but not sufficient for that estate's emissions to actually leave the stack.

The Global FID Deficit & Macroeconomic Bottlenecks

Even where UK-specific engineering proceeds on schedule, CB7's industrial pathway sits inside a global CCUS financing environment that has historically failed to convert announcements into built capacity.

The Final Investment Decision (FID) Gap

  • Global CCUS financing reviews consistently find that roughly 90% of internationally announced carbon capture capacity has failed to reach Final Investment Decision, typically stalling on capital expenditure volatility, uncertain long-run carbon price signals and the absence of a bankable offtake structure for captured CO2.
  • This matters for CB7 because East Coast Cluster and HyNet are the exceptions that proved bankable — not evidence that the model scales easily to Track-2 and beyond. Each additional cluster has to independently clear the same FID hurdle that eliminated nine in ten global projects.
  • Capital expenditure horizons for subsea trunk pipelines and offshore injection wells routinely run 20–25 years before full payback, a duration mismatch against typical private infrastructure fund cycles that only state-backed contracts-for-difference or equivalent revenue support mechanisms have so far bridged.

The Infrastructure Sequencing Delay

  • The UK Government's £21.7 billion funding commitment over 25 years provides the revenue floor that made East Coast Cluster and HyNet's FIDs possible — but it funds operating support, not a shortcut through construction physics.
  • Common-user trunk pipelines and offshore injection wells must be substantially complete before individual factory emitters can safely connect, creating an inherent lead-time bottleneck: the trunkline is a prerequisite, not a parallel workstream, for every downstream emitter counting on it for CB7 compliance.
  • This sequencing risk compounds down the supply chain — an individual cement or glass plant cannot bank its own CB7-linked abatement claim until its specific tie-in point is commissioned, regardless of how advanced its on-site capture plant is.

The National Wealth Fund (NWF) Layer

  • The restructured National Wealth Fund is positioned to de-risk private co-investment in the next tranche of clusters — principally Scotland's Acorn project and the Humber's Viking CCS — both categorised as Track-2 and therefore behind East Coast Cluster and HyNet in the financial-close queue.
  • NWF's role is to narrow the same FID gap described above by taking a first-loss or co-investment position that lowers the capital cost private infrastructure funds would otherwise demand for CCUS-specific risk — geological storage performance, injection ramp-up and long-duration offtake risk chief among them.
  • The arithmetic constraint is time, not intent. Track-2 clusters reaching FID on a similar timeline to Track-1's historical schedule implies construction, commissioning and ramp-up windows that leave limited slack before the 2038–2042 budget period begins — meaning any further slippage in Acorn or Viking's financial close compresses an already tight delivery runway rather than merely delaying it.

The Verdict: A Narrow, Sequencing-Dependent Path

CB7's industrial abatement target is not unachievable on the geology or the chemistry — Endurance and the Liverpool Bay depleted fields have adequate storage capacity, and calcination emissions are a known, capturable stream. What the target is exposed to is sequencing risk: trunk pipelines must precede injection wells, injection wells must precede emitter tie-ins, and Track-2 FIDs must land within a narrowing window before the 535 MtCO2e ceiling takes effect. The £21.7 billion funding settlement and the National Wealth Fund's co-investment role solve the financing problem that killed 90% of comparable global projects — they do not solve the construction-physics problem of drilling wells and laying pipe fast enough to matter before 2038.