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CA Utilities Unveil Distribution Resource Plans

James Hansell — July 9, 2015

On July 1, 2015, California’s investor-owned utilities (IOUs) submitted the first iterations of their Distribution Resource Plans (DRPs), detailing how to integrate distributed energy resources (DER) into their distribution systems. For reference, DER includes energy efficiency, demand response, rooftop solar, combined heat and power, electric vehicles, and energy storage.

The IOUs organized their filings around the California Public Utilities Commission (CPUC) guidance released in February under Rulemaking 14-08-013, taking approaches specific to their territories. The DRPs come at the intersection of increased DER deployments and the pending replacement of significant amounts of the state’s conventional electric grid. This confluence of changes in generation on the supply and demand sides of customers’ electric meters highlights the growing need to develop accurate and widely accepted valuations for all types of energy resources. Satisfying this need will enable wider DER integration into IOU resource adequacy and long-term procurement planning proceedings; a critical path to realizing the emerging opportunities materializing in the Energy Cloud and a more dynamic, responsive, and decentralized California electric grid.

Integrated Capacity Analysis

One of the most important questions that the DRPs address is the extent to which the grid is able to integrate DER without significant changes. The IOUs developed a common methodology to quantify this capacity, calculating the number of DER that can be installed on a circuit without violating voltage requirements, equipment thermal ratings, protection scheme limits, or safety standards. The results of the analyses have been provided as online maps by Pacific Gas & Electric (PG&E), Southern California Edison (SCE), and San Diego Gas & Electric (SDG&E).

SCE DER Interconnection Map

SEC DER Interconnection Map

(Source: Southern California Edison)

The CPUC expects these interconnection maps will help direct third-party DER investments toward more beneficial locations. The commission guidance requires the analysis to be performed down to individual circuit segments, and the variable nature of distributed resources necessitates an intraday time scale. This modeling approach represents a significant increase in locational and temporal granularity as compared to existing distribution planning approaches.

Optimal Location Benefit Analysis

In addition to the engineering analysis establishing integration capacity, the DRPs include a study of the financial impacts of all distributed resources. The framework was created jointly by the IOUs and includes guidance from the More Than Smart working group. The framework enhances previous tools to include the locational detail and dynamic timing required to accurately value DER contributions. The value components from the SCE filing are shown in the following table.

SCE Value Components

SCE Value Components

(Source: Southern California Edison)

The DRP locational benefit analysis considers many of the same questions as the CPUC’s Net Energy Metering Successor Tariff proceeding, though it remains to be seen how closely the two proceedings will be coordinated. The DRPs are a critical first step toward integrating DER into electric system planning, and hopefully the beginning of fruitful convergence of utilities, consumers, and third-party provider interests.

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