1. DN Interruption Reform (UNC Mod 90) Liz Spierling Commercial Manager, Transportation

2. Interruption Requirements The following slides depict indicative interruption requirements for the WWU LDZs The numbers are based on 2006 demand forecasts, 2006 OCS process and 2006 Network Planning models The numbers WILL be reviewed and WILL change prior to publication of the Interruption Requirements for the 2008 tender process.

3. Generic ZoneConnected energy GWh/d Amount of energy available for interruption GWh/d Amount of energy required by WWU for interruption GWh/d Aylesbeare 25.793.370.25 Central 70.157.160.78 Cirencester 10.041.61.31 Northern 148.2319.292.67 Southern 84.9213.311.52 Wales Southern System Aylesbeare System Central System Northern System Cirencester System Energy required has been assessed based on 2010 network models and is indicative. Actual requirements will be published in 2008.

4. Wales North Wales South- West System Generic ZoneConnected energy GWh/d Amount of energy available for interruption GWh/d Amount of energy required by WWU for interruption GWh/d Wales North 61.7514.48TBA WS-Central System 132.0747.3816.81 WS-East System 57.8221.547.14 WS-Locational zone 0.14 WS-West System 51.759.835.82 Wales South- Central System Wales South- East System Locational zone Energy required has been assessed based on 2010 network models and is indicative. Actual requirements will be published in 2008.

5. DN Interruption Accurate AQ and SOQ information will benefit everyone –Users will pay firm charges from 2011 onwards –Capacity charges are based on SOQ –DNs model their Networks based on contracted values

6. Interruption Pricing “Ready Reckoner” Model demonstrated is “Work in Progress” Welcome feedback on: –Is it useful? –Where should it be published? –Are there more scenarios needed?

7. DN Interruption Next steps DNs have publish Interruptible Charging Methodology WWU will publish indicative Interruption Requirements WWU will hold 2 further Customer / Shipper Seminars in January 2008 Ofgem will include detail on incentives in Final Proposals (3/12/07) DNs publish Invitation to Tender in May 2008 Interruption Contracts awarded in June/July 2008 for gas years beginning October 2011