How the Grid Is Planned to Support Growth, Electrification, and Reliability

What is the Distribution Planning Process?

Southern California Edison’s Distribution Planning Process (DPP) is the formal, recurring planning process to ensure the electric distribution grid can safely, reliably, and efficiently serve customers today and years into the future. The DPP is conducted annually and is refined each year as conditions, policies, and customer needs change.

The annual DPP is designed to:

•  Anticipate and identify where electric demand will grow, resulting in existing infrastructure to reach its limits
• Plan grid upgrades before reliability is affected
• Integrate customer projects (including known and pending customer projects), electrification, and DER adoption
• Provide transparent, repeatable planning outcomes reviewed by regulators and stakeholders

What the DPP Is not: 

• Not a construction schedule
• Not a guarantee of immediate capacity
• Not a replacement for energization applications or service requests 

Inclusion in planning does not equal load reservation — but exclusion from planning significantly increases risk of delay.

Why the DPP Matters to Customers and Communities:

Electric infrastructure takes time to plan, permit, and build. As California experiences: increased housing and economic development, rapid transportation electrification, building electrification and decarbonization, growth in distributed energy resources, the distribution grid must evolve proactively.

Without early planning:

• Capacity constraints may arise unexpectedly
• Upgrade options become more limited
• Customer projects face longer energization timelines

The DPP Annual Planning Cycle (End‑to‑End)

The DPP follows a repeatable annual lifecycle, which is why customer input at any point in the year can still influence outcomes.

Step 1: Load Information Collection

SCE begins by assembling information on current and future electric demand, including:

• Existing customer usage
• Historical demand trends
• Pending customer loads, such as:
  • Approved but not energized developments
  • Large commercial and industrial projects
  • Transportation electrification infrastructure
  • Major residential growth
• Distributed Energy Resources (DERs):
  • Solar PV
  • Energy storage
  • Energy efficiency
• State and regional demand forecasts

This information is gathered from multiple sources and mapped to specific locations on the grid.

Step 2: Load Forecast Development

Using this information, SCE develops multi‑year load forecasts, typically covering a 5–10 year lookahead.

Key characteristics of the forecast:

• Demand forecasting is performed at each level of the electrical grid hierarchy, including feeders, substation, and circuits.
• Forecasts reflect:
  • Residential and non‑residential demand
  • Electrification trends
  • DER adoption
  • Pending customer projects
• Forecasts are updated annually to reflect new information

Even projects that are still in early planning can affect forecasts if they are shared early.

Step 3: Identification of Grid Needs

SCE evaluates whether forecasted demand will exceed safe operating limits, including:

• Thermal capacity limits
• Voltage performance thresholds
• Reactive power requirements
• Reliability criteria

When limits are forecasted to be exceeded, that location is identified as a grid need.

Each grid need:

• Is traceable through a unique identifier
• Has an estimated timing (when the deficiency emerges)
• Is tied to specific infrastructure

This step allows us to understand where the grid needs to change in order to support growth.

Step 4: Evaluation of Solutions

Once grid needs are identified, SCE evaluates solutions using a cost-effectiveness hierarchy:

First: Optimize Existing Assets

• Load transfers
• Operational adjustments
• Configuration changes

Then: Plan Physical Upgrades

• Circuit upgrades or reconductoring
• New circuits
• Substation expansions
• New substations
• Voltage or reactive power equipment 

DER solutions may also be evaluated where appropriate and reliable.

Each option is assessed for:

• Timing
• Reliability benefits
• Cost
• Scalability

Step 5: Public Reporting and Transparency

Results of the DPP are published through:

• Grid Needs Assessment (GNA) – where grid constraints exist
• Distribution Upgrade Project Report (DUPR) – how SCE plans to address them

These annual reports and other planning data are publicly available through public planning portals and stakeholder engagements.