Aging Infrastructure Management and Challenges Sue Fleck Vice President Pipeline Safety Trust “Getting to Zero’ Conference 2011

2 Contents  Background – National Grid  Distribution Industry Metrics  Recent Safety Performance  Preventative Measures  Fitness for Service  Material Considerations  Main Inventory by Material  One New England Example

3 US Gas Distribution NY NH MA RI Operating in: MA, NH, NY & RI Approx: 3.5 mil Customers 2.6 mil Service Lines 1,800 Stations 36k mi Distribution Main 29k mi Service Piping 500 mi Transmission Main

4 Distribution Industry Metrics  2.1 million miles of main  65 million services  Age from brand new to over 100 years old  Size from ½” to over 36” in diameter  Materials: Cast Iron, Bare Steel, Cathodically Protected Steel, Plastics

5 Distribution Safety Performance Leaks & Incidents Note: Leak and mileage data for 2010 is not yet available Incidents are per 10,000 miles using 2009 miles. Leaks Significant Incidents Serious Incidents

6 All Natural Gas Distribution Incidents by Causes

7 Decade of Installation for Facilities All Gas Distribution Incidents

8 Materials Involved in Natural Gas Distribution Incidents

9 Preventative Measures  Actions distribution companies are taking to avoid incidents  Perform leakage surveys  Perform corrosion surveys  Patrol pipelines  Inspect facilities  Perform pipeline location marking  Monitor operations metrics  Determine fitness for service

10 Fitness for Service  Defined as the ability of different types of facilities or components to satisfactorily perform; delivering gas safely and reliably  Track and trend condition and performance  Age  Material  Maintenance records i.e., leaks/mile, /service…  Operating records i.e., pressures, flows…  Determine whether to repair, rehabilitate or replace facilities based on a risk assessment

11 Main Inventory by Material

12 Material Considerations  Plastic – material of choice for services and mains in distribution system operating at lower pressures  Non-corrosive  Subject to excavation damage  Cast iron – installed until the 60’s for mains and large diameter services  Corrosion resistant  Susceptible to cracking  Joints susceptible to leakage  Steel – material of choice for mains and services at high pressures and mains of large diameter  Can be protected from corrosion  Resistant to excavation damage  Expensive to install

13 One New England State Example  Instituted a Safety and Reliability Program to replace infrastructure demonstrated to be leak prone  Approximately 3,000 miles of pipe, half leak prone  Includes all replacement programs  Programs must be pre-approved by commission  Level of spending must be pre-approved by commission  Eliminates regulatory lag  Annual reconciliation filing required  Ramped up pipe replacement program mileage from single digits to approximately 50 miles per year