Bottleneck analysis
Forward capability against the backward requirement for Yorkshire — REL. The constraint list is ranked by capacity, not by opinion.
Forward achievable
7,735.7Nm3/day
Backward required
20,472Nm3/day
Production gap
-12,736.3Nm3/day
Extra feedstock needed
196.3t/day
Binding constraint
The single stage setting plant throughput today.
Root cause
Reception/TMA processing rate or operating window limits intake.
Intervention
Extend the operating window, add a shift, or uprate the TMA line carrying the larger share.
+2,414.7 Nm3/day released before the next constraint binds (Digestion)
Risk introduced
Longer operating windows may breach permit delivery restrictions.
Shortfall against requirement: 196.3 t/day · lost gas 12,883.2 Nm3/day
Constraint ladder
Removing one constraint promotes the next. This is the order in which capacity will unlock.
| Rank | Stage | Capacity t/day | Required t/day | Shortfall | Lost gas Nm3/day | Intervention |
|---|---|---|---|---|---|---|
| 1 | Reception / TMAbinding | 117.9 | 314.1 | 196.3 | 12,883.2 | Extend the operating window, add a shift, or uprate the TMA line carrying the larger share. |
| 2 | Digestion | 154.6 | 314.1 | 159.5 | 10,468.4 | Add digester volume, dilute the feed, or rebalance allocation across digesters. |
| 3 | Soup production & storage | 235.7 | 314.1 | 78.4 | 5,147.5 | Uprate the soup production line or extend soup-making hours. |
| 4 | Biogas upgrading (BUU) | 289.1 | 314.1 | 25 | 1,643.6 | Uprate or add BUU capacity, or reduce CHP/boiler gas draw. |
| 5 | Grid entry (NEA) | 310.2 | 314.1 | 3.9 | 259 | Negotiate a higher NEA limit, add storage, or divert surplus to CHP. |
| 6 | Feedstock supply | 313.2 | 314.1 | 1 | 63 | Secure additional feedstock or reduce the contamination/rejection fraction at reception. |
| 7 | Hydrolysis | 329.4 | 314.1 | 0 | 0 | Raise hydrolysis temperature, uprate the feed pump, or add working volume. |
| 8 | Transport | 466.7 | 314.1 | 0 | 0 | Add a tanker, increase payload, cut shunting/travel time, or approve parallel load/unload. |
| 9 | Pasteurisation | 608.6 | 314.1 | 0 | 0 | Add a tank, shorten non-hold cycle elements, or improve heat recovery to cut heat-up time. |
Backward chain
Working back from the grid target to the feedstock tonnage the plant would need at the gate.
| Step | Requirement | Basis |
|---|---|---|
| Grid injection target | 20,472 Nm3/day | Annual target divided by operating days |
| Propane enrichment | 955.6 Nm3/day | GCV energy balance to the network entry specification |
| Biomethane | 19,516.4 Nm3/day | Target less the propane contribution |
| Biogas to BUU | 33,040.3 Nm3/day | Divided by CH4 content and BUU methane recovery, plus CHP draw |
| Digester push | 305.7 m3/day | Yield basis in reverse, sharing the forward chemistry |
| Pasteurised volume | 305.7 m3/day | Equal to digester push, no interstage loss modelled |
| Soup required | 305.7 t/day | Converted at the blend density |
| Feedstock at the gate | 314.1 t/day | Grossed up for the contamination rejection rate |
| Tanker loads | 11.3 /day | At the configured payload |