Project Peak Valley Risk

Why this project exists

Public discussion of the Peak Cluster pipeline so far has been polarised. Concerns raised by residents have been labelled "misinformation". Reassurances from developers and elected representatives have leaned heavily on analogies to dissimilar systems — US CO₂ pipelines through sparsely populated rural plains, Norwegian offshore CCS — that don't apply to a 195 km route through karst, salt subsidence, flood-prone valleys, and populated terrain.

The honest answer is that no one yet has the validated science to assess this specific route. The UK Health and Safety Executive, the Department for Energy Security and Net Zero, and DNV are currently running Project Skylark — a three-year joint industry project that is still developing:

• Validated CO₂ dispersion models for varied terrain
• Emergency response best practices
• Safety guidelines for pipeline routing, risk assessment, and venting

That work will not finish in time for the planning decision. Project Peak Valley Risk fills the interim gap with the best publicly defensible analysis we can build right now.

What the project does

1. Give residents a secondary source of scientific quantification that is grounded in research methods.
2. Map the route accurately. Pipeline corridor, indicative construction zone, and distance bands — all derived from Peak Cluster's own published GIS data and rendered openly.
3. Quantify population exposure. 2021 Census populations redistributed to UK Centre for Ecology & Hydrology 25 m built-up land cover (a dasymetric method), then summed within distance bands from the construction zone.
4. Model CO₂ leak dispersion using terrain-aware heavy-gas dispersion approaches, accounting for the gravity-driven flow of dense-phase CO₂ down valleys and into low-lying ground.
5. Publish everything. Inputs, code, intermediate datasets, and conclusions — all open to challenge.

Technical methodology

• Source-term modelling in OpenFOAM. Computational fluid dynamics (CFD) simulation of the rapid depressurisation of a 24-inch DN600 dense-phase CO₂ pipeline rupture at the project's stated operating pressure (~150 bar, ~10°C), capturing the supersonic jet, Joule-Thomson cooling to −78°C, and the dry-ice/vapour two-phase plume that forms in the first seconds after release.
• Atmospheric boundary conditions from WRF. Weather Research and Forecasting model (WRF-ARW) at 1–3 km nesting over the Peak District and Cheshire Plain, tuned to representative night-time inversion, daytime convective, and high-wind storm scenarios — the meteorology that actually drives heavy-gas dispersion behaviour.
• Digital twin of the Peak District & Cheshire valleys. 2 m LIDAR DTM (DEFRA Composite) for the corridor, OS Open Greenspace and OS Open Roads for surface roughness, OS Open Buildings and OS Open UPRN for receptor locations — assembled into a meshed terrain that drives both the CFD domain boundary and the receptor exposure analysis.
• Heavy-gas dispersion downwind. Coupling of CFD source-term output to PHAST-equivalent dense-gas dispersion and validated against the COSHER and Spadeadam large-scale CO₂ release datasets (the same dataset DNV's Project Skylark is currently extending). Dose × time exposure thresholds applied per the HSE's CD/SLOD framework for CO₂.
• Receptor exposure quantification. Every UPRN within the modelled plume footprint is tagged with peak concentration, time-integrated dose, and time-to-incapacitation. Aggregated to civil parish, BUA, LSOA and LAD for community-level reporting.
• Open scripts & data. All inputs, mesh definitions, OpenFOAM cases, WRF namelists, and post-processing notebooks published openly. Parameters chosen to bracket plausible ranges rather than single point estimates, so independent reviewers can probe the assumptions.

Interactive distance map

The map below shows the pipeline corridor, the indicative 30 m construction zone (the strip where the pipe would actually be dug), and contoured distance bands across Cheshire, Derbyshire and the Wirral. Hover anywhere to see the distance to the construction zone. Use the menu (bottom-left) to inspect population exposure for specific places — including Macclesfield, Bollington, Whaley Bridge, Buxton, Wirral as a borough, and Cheshire / Derbyshire as wholes.

Headline findings (current)

Cumulative population within these distances of the pipeline centreline. Population derived from the 2021 Census, redistributed to OS Open UPRN address points within each LSOA (so every house, isolated farm, and small village is captured directly):

By area

Top 50 places ranked by population within 500 m of pipeline centreline

UPRN-derived dasymetric population, civil parish (with BUA fallback for unparished urban areas). Cumulative figures.

What we are working on

• Heavy-gas dispersion modelling — terrain-aware simulations of plausible release scenarios at multiple points along the route, including night-time releases under temperature inversion.
• Geological hazard mapping — overlaying the route with British Geological Survey GeoSure data for karst dissolution, salt subsidence, and ground movement.
• Flood vulnerability — Environment Agency flood zones, river crossings, and the historical flood frequency record for the corridor (2019, 2020, 2021, 2023, 2024, 2025).
• Emergency response analysis — what would actually happen if a release occurred at a populated point in the corridor, given current UK fire and ambulance service capability.

Data sources

• Peak Cluster ArcGIS scoping boundary — Peak Cluster Limited via ArcGIS Online
• 2021 Census TS001 — Office for National Statistics, via NOMIS
• LSOA 2021 boundaries — ONS Open Geography Portal
• UKCEH Land Cover Map 2023, 25 m — UK Centre for Ecology & Hydrology
• British Geological Survey GeoSure — BGS Open Data
• Project Skylark — DNV / HSE Science Division joint industry project
• PHMSA pipeline incident database — US Department of Transportation