Dewey Day Principal OT Architect Electric Protection over Carrier Switched Ethernet Services Pacific Gas & Electric Dewey Day Principal OT Architect

What We Did Before - 4 Wire Lease Architecture SCADA Master and FEPs have Many Modems Multiple Leases with No Aggregation Drives Up Costs Many Multi-Carrier Leases Lower Reliability Extended Outages Point-to-Point Leases Difficult to Troubleshoot Limited Monitoring Capabilities Copper Cable HVP Difficult to Engineer Limits Bandwidth Growth Safety Concerns High Expenses Escorting Telco Techs

PG&E Lease Line Overview 1457 Facilities Served with Telephone Company Leases Leased Functions 266 Energy Management System Leases 949 SCADA Leases 403 Protective Relaying Leases 146 SPS/RAS Leases

What We are Doing Now - T-1 Lease Architecture Reduction in Modems at SCADA Masters and FEPs Aggregation of Circuits Reduces Lease Line Costs Fiber Entrance Facilities Improves Reliability of Leases Reduced Multi-Carrier leases Centralized Lease Architecture Improved Monitoring Reduced Outage Migration to PG&E Infrastructure Reduces Lease Costs Fewer Leases Reduces Complexity Channel Bank Enables Growth Fiber Entrance Enables Higher Bandwidth Services Fiber Eliminates Safety Issues with HVP

What We Are Testing – Carrier Switched Ethernet AT&T Private Line Decommissioning Page 5

Why We Think it Might Work…. Service Level Agreement from AT&T Switched Ethernet Service Guide