EDISON INTERNATIONAL

Major Transmission Projects

A summary of SCE's most significant transmission and substation construction projects is presented below. The timing of the projects below is subject to timely receipt of permitting, licensing, and regulatory approvals.

1 Direct expenditures include direct labor, land, and contract costs incurred for the respective projects and exclude overhead costs that are included in the capital expenditures forecast discussed in "Management Overview—Capital Program."

2 Direct expenditures were adjusted for inflation with no change to the scope of the project.

Riverside Transmission Reliability Project

The Riverside Transmission Reliability Project is a joint project between SCE and Riverside Public Utilities ("RPU"), the municipal utility department of the City of Riverside. While RPU will be responsible for constructing some of the project's facilities within Riverside, SCE's portion of the project consists of constructing upgrades to its system, including a new 230 kV substation; certain interconnection and telecommunication facilities and overhead transmission lines in the cities of Riverside, Jurupa Valley, and Norco and in portions of unincorporated Riverside County. SCE began construction in June 2025. The current cost estimate of the project is $748 million and the project is expected to be completed in 2029.

Alberhill System Project

The Alberhill System Project consists of constructing a new 500 kV substation, two 500 kV transmission lines to connect the proposed substation to the existing Serrano-Valley 500 kV transmission line, telecommunication equipment, and subtransmission lines in western Riverside County. The project was designed to meet long-term forecasted electrical demand in the proposed Alberhill System Project area and to increase electrical system reliability and resiliency. In June 2024, the CPUC issued an addendum to its 2017 Final Environmental Impact Report, concluding its California Environmental Quality Act review. The project is now seeking final CPUC approval to begin construction. SCE is expecting the final CPUC decision in the first quarter of 2026.

Eldorado-Lugo-Mohave Upgrade Project

The Eldorado-Lugo-Mohave Upgrade Project will increase capacity on existing transmission lines to allow additional renewable energy to flow from Nevada to Southern California. The project would modify SCE's existing Eldorado, Lugo, and Mohave electrical substations to accommodate the increased power flows from Nevada to southern California; increase the power flow through the existing 500 kV transmission lines by constructing two new capacitors along the lines; raise transmission tower heights to meet ground clearance requirements; and install fiber optics on the transmission lines to provide communications between existing SCE substations. In August 2020, the CPUC approved the certificate of public convenience and necessity ("CPCN") for the project.

Construction for the project began in November 2020. The total costs for the Eldorado-Lugo-Mohave Upgrade Project are expected to exceed amounts currently approved in the CPCN granted by the CPUC due to delays in regulatory approvals, contractor performance issues, supply chain constraints, COVID-19 impacts, and the availability of CAISO outage windows. SCE's petition for modification ("PFM") to increase the direct expenditures for the project from $247 million to $319 million was approved by CPUC and the project went into service in 2025. Additional work after the in-service date is required to mitigate the impact of the project on nearby natural gas transmission lines. In January 2026, SCE filed a second PFM to request an approximately $48 million to address the additional costs of the mitigation work. The mitigation work is expected to be completed in 2026.