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Bacton blending feasibility study
Gas Quality Workshop
23 April 2007
Dr Nick Bates, National Grid Gas Transmission
Bacton blending feasibility study
Scope ABB report National Grid view on findings Summary
Bacton Blending - Scope
Blending only
Assume sufficient compliant gas available
Bacton Blending - Scope
Blending only
Assume sufficient compliant gas available
Allow minor modifications to assets
Bacton Blending - Scope
Blending only
Assume sufficient compliant gas available
Allow minor modifications to assets
Gas leaving the site must be compliant with
GS(M)R
Bacton Blending - Scope
Blending only
Assume sufficient compliant gas available
Allow minor modifications to assets
Gas leaving the site must be compliant with
GS(M)R
Define response requirements for measurement
and control (valve)
Bacton Blending – ABB Findings
It is feasible to implement a measurement and control system for blending at Bacton
Bacton Blending – ABB Findings
It is feasible to implement a measurement and control system for blending at Bacton
The Bacton pipework provides a non-ideal blending arrangement
BactonIdeal
Bacton Blending – ABB Findings
It is feasible to implement a measurement and control system for blending at Bacton
The Bacton pipework provides a non-ideal blending arrangement
Control system would depend on feed-forward control
GQ
Feed forward
GQ
Feedback
Set point
LimitSafety Margin
Bacton Blending – ABB Findings
It is feasible to implement a measurement and control system for blending at Bacton
The Bacton pipework provides a non-ideal blending arrangement
Control system would depend on feed-forward control Transient changes in gas quality are a significant issue
Bacton Blending – ABB Findings
It is feasible to implement a measurement and control system for blending at Bacton
The Bacton pipework provides a non-ideal blending arrangement
Control system would depend on feed-forward control Transient changes in gas quality are a significant issue Some supplies are connected at Bacton in a way that
makes blending infeasible, e.g. BBL supply
Bacton blending – National Grid view
Whilst it is feasible to implement blending measurement and control there are implications for National Grid and the gas industry
The blending depends on sufficient compliant gas to blend with non-compliant gas
The control system would have an effect on flows – potentially including end of day quantities
Further detailed work would be required to make a case that the blending system would not increase the risk of unsafe gas within the UK gas network
Implementation of blending could introduce constraints within the remainder of the Bacton site
Bacton blending - Summary
It is feasible to install a blending measurement and control system at Bacton but further work is required to demonstrate that there would not be a significant additional gas quality risk
Any service is likely to be constrained and may only be available on an interruptible basis
The constraint on operation may include the NTS downstream of the Terminal
Whilst only Bacton has been studied, similar issues are anticipated at other National Grid entry points
