THE DIGITAL GARDENS OF THE NORTH TYNE VALLEY — PHYSICAL MODEL V8
England screening model • 10 October 2026

Open the XLSX workbook and edit the yellow input cells. Its Energy and Results
sheets contain live formulas. Agriculture and Farm processing are separate,
illustrative scenarios. Run `python3 model.py --sensitivity` to reproduce the
annual energy results using only Python's standard library. Inputs are in
assumptions.json; machine-readable outputs are in results.json and results.csv.

RECONCILED SCHEDULE
Kielder 6.5; Falstone 3; Tarset & Greenhaugh 3.5; Bellingham 4; Wark 2;
Humshaugh & Chollerford 5.5 MW. Total 24.5 MW. Hexham is the gateway.
This follows the six capacities printed in the V6 website table and its 4 MW
Bellingham plan. The previous 35 MW screening schedule is superseded. Historical
files retained elsewhere in the site are legacy records, not the current design.

CENTRAL CASE
IT electricity: 193.158 GWh/year. Useful heat: 82.09215 GWh/year.
Project electricity, including delivery pumps: 223.773543 GWh/year.
Unmatched grid imports: 22.3773543 GWh/year.
Comparator: 53,308.292121 tonnes CO2e/year.
Project: 2,930.538319128 tonnes CO2e/year.
Avoided: 50,377.753801872 tonnes CO2e/year (94.5026595253%).
Wind plus solar: 303.534 GWh/year. No export credit is taken.

EQUATIONS AND UNIT CONVERSIONS
IT GWh = total MW * annual hours * load fraction / 1000.
Useful heat = IT GWh * capture fraction * annual heat-use fraction.
Comparator facility GWh = IT GWh * reference PUE.
Project GWh = IT GWh * project PUE + useful heat * pump coefficient.
Displaced gas GWh = useful heat / gas-boiler gross-CV efficiency.
Grid imports = project GWh * (1 - matched-renewable fraction).
Emissions tonnes = GWh * kgCO2e/kWh * 1000.
Comparator emissions = reference electricity emissions + gas emissions.
Avoided emissions = comparator emissions - project emissions.
Reduction = avoided / comparator. This is a conditional prediction.

BOUNDARY
Equal IT workload and useful heating service; annual operational Scope 1 and 2.
The 90% renewable share means valid hourly/contractual matching for the project,
not a conclusion from annual output. Low-grade heat is usable only if it meets
the customer temperature. No heat pump is modelled. Heat-network pumping is
outside PUE and explicitly added. Storage losses are represented by the annual
heat-use assumption; improve this with measured hourly demand and delivery data.
Excluded: grid transmission/distribution, upstream fuel, equipment manufacture,
construction, food/livestock emissions, household transport and carbon removal.
This is not a whole-community or lifecycle inventory. No farm carbon tonnes,
export or separate avoided-manure/biogas credit is added to the headline result.

SOURCES
DESNZ UK greenhouse-gas conversion factors for company reporting, full set 2026:
https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2026
UK electricity, generated: 0.13096 kgCO2e/kWh.
Fuels, natural gas: 0.18231 kgCO2e/kWh gross calorific value.
The boiler efficiency is on the same gross-CV basis.
Other values are transparent engineering screening assumptions, not site data.

FARM SCENARIOS
Inherited mechanism weights predict illustrative beef reduction of 34.25% and
cheese reduction of 53.75%. They are not measured British product footprints.
No near-98% seaweed methane-reduction claim is used in the default case. Validate
feed legality and performance by animal category and production system.
Sterling processing inputs are scenarios, not current price quotations. The
139-head jerky scenario gives 19,460 kg/year and a £46,217.50 farmer margin
share. The 126-cow cheese scenario gives 88,200 kg/year and £154,350 incremental
processing margin. Fixed overheads, maturation inventory, capital, tax and
financing are excluded. These are not guaranteed farm income.

NEXT ENGINEERING WORK
Validate electrical connection, land, fibre routes, thermal grade, hourly demand,
generation profiles, contractual matching, ecology, water permissions, planning,
farm volumes, costs and product footprints before making verified claims.
