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 Limit Safety 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