Site twin
Forward model from feedstock reception to grid entry for Yorkshire — REL. Every figure is traceable to a variable with a recorded source.
Data source: Yorks Process Flow v1 (07/08/26, Merged Models)
Yorks_Process_Flow-v1-070826-Merged_Models.xlsx — 47 of 64 variables read from 2 sheets (118 cells captured). The two earlier workbooks are retired and are kept only for comparison on the Reconciliation screen.
Where the site stands
Yorkshire — REL can currently deliver 7,735.7 Nm3 of gas a day, which is 37.8% of what the annual grid contract needs. The shortfall is 12,736.3 Nm3 a day. The limit is reception / tma: it can handle 117.9 tonnes a day where 314.1 tonnes a day would be needed to hit the target. Extend the operating window, add a shift, or uprate the TMA line carrying the larger share.
Evidence score is 76 out of 100 — sound enough to plan against. Only 0% of the inputs are measured on this site and 11% are assumptions, so quote the range 6,993.1 to 8,315.9 Nm3 a day rather than the single figure.
Grid injection
322.3Nm3/h
2.82 million Nm3/yr at 365 operating days
Target achievement
37.8%
Gap of 12,736.3 Nm3/day against the NEA-derived target
Binding constraint
Reception / TMA
Capacity 117.9 t/day against 314.1 t/day required
Data quality
76/100
0% measured · 11% assumed · 0% unvalidated
Process chain
Each stage is sized independently. The lowest capacity sets plant throughput; everything above it is idle headroom.
- Planned t/day
- 321.86
- Rejected t/day
- 8.68
- Weighted DS %
- 16
- Weighted VS (%DS)
- 85
- Availability
- 100%
Accepted tonnage is planned tonnage less the contamination/rejection fraction of each feedstock.
- Solid line t/day
- 117.86
- Liquid line t/day
- 117.86
- Solid share %
- 0
- Operating hours/day
- 9.43
- Availability
- 100%
Each reception line is sized against its own share of the blend, not against total tonnage.
- Soup rate t/h
- 25
- Soup capacity m3
- 425
- Start stock m3
- 0
- Minimum stock m3
- 25
- Availability
- 100%
Storage volume itself is a buffer, not a throughput limit; the soup production rate is the limiting term.
- Route
- Changing Waste → REL
- Cycle minutes
- 55.2
- Mode
- Sequential load/unload
- Loads per tanker per shift
- 11
- Loads per day
- 17.29
- Availability
- 100%
Sequential mode is the default interpretation of the workbook tanker cycle.
- kh effective /day
- 0.21
- Required retention days
- 6.61
- Pump-limited m3/day
- 712.9
- Retention-limited m3/day
- 329.36
- Binding term
- Retention time
- Availability
- 99%
First-order kinetics: kh_eff = kh_ref x theta^(T-Tref) x solids factor x pH factor; retention = -ln(1-x)/kh_eff.
- Cycle minutes
- 180
- Batches per tank per day
- 8
- Compliant batches per day
- 24
- Approved regime
- 70degC for 60 min
- Compliance gate
- PASS
- Availability
- 97.5%
Compliance gate satisfied against the site's approved treatment regime, monitoring evidence still required.
- Total working volume m3
- 8,000
- Hydraulic limit m3/day
- 266.67
- VS organic limit m3/day
- 205.88
- COD organic limit m3/day
- 164.38
- Legacy DS-load limit m3/day
- 250
- Availability
- 94.1%
Hydraulic and organic constraints are evaluated separately. The DS-load rule from the workbook is retained for comparison but is not a complete organic loading calculation.
- Nameplate Nm3/h
- 1,500
- Proven Nm3/h
- 1,350
- Biogas offered Nm3/h
- 520.2
- Headroom Nm3/h
- 755.83
- Methane recovery %
- 98
- Availability
- 94.5%
Proven operating capacity is used for the constraint; nameplate is retained for comparison.
- NEA limit Nm3/h
- 853
- Injection Nm3/h
- 322.32
- Headroom Nm3/h
- 526.01
- Propane ratio
- 0.05
- Reference conditions
- Nm3 (0degC, 101.325 kPa)
- Availability
- 99.5%
Propane volume = biomethane x (target GCV - biomethane GCV) / (propane GCV - target GCV). All gas volumes are Nm3 (0degC, 101.325 kPa).
Blend chemistry
Weighted across accepted tonnage, net of contamination rejected at reception.
| Feedstock | t/day | Share | VS t/day | CH4 share |
|---|---|---|---|---|
| Changing Waste — depackaged soup | 205.3 | 65.6% | 27.93 | 65.6% |
| High-strength liquids & BioteCH4 soup | 107.8 | 34.4% | 14.67 | 34.4% |
- Weighted DSworkbook
- 16%
- Weighted VS (of DS)
- 85%
- COD loadworkbook
- 91.45 t/day
- C:N ratio
- 16
- Blend pH
- 5.5
- Rejected
- 8.7 t/day
Biology and heat
Yield derates and the site heat balance behind the gas numbers.
Biological efficiency
Methanogenic activity is a piecewise curve peaking at 40-44degC, not the Arrhenius curve used for hydrolysis.
Heat chain (kWh/day)
HRT
67.9 days
OLR (VS)
2 kg/m3/d
OLR (COD)
4.3 kg/m3/d
DS load
2.36 kg/m3/d
CH4 per t wet feed
63.8 Nm3
Soup cover
81.5 h
Tanker loads
4.4 /day
Confidence band
6,993.1 – 8,315.9 Nm3/d