California Regulators Modify Grid Map Requirements to Ease Solar Integration

Integration Capacity Analysis models grid conditions that impact where distributed energy resources can be added, without the need for costly upgrades or lengthy interconnection studies.

The California Public Utilities Commission ordered several key improvements to the Integration Capacity Analysis, a grid transparency tool.

The motion requesting the changes that the CPUC responded to was filed last October by the Interstate Renewable Energy Council, the California Solar & Storage Association, and California Energy Storage Alliance. Regulators issued their decision at the end of the January.

Integration Capacity Analysis (ICA), called hosting capacity analysis in other states, is a process of modeling conditions on the distribution grid that impact where additional distributed energy resources can be added without the need for costly upgrades and/or lengthy interconnection studies.

The maps  can be critical tools for enabling more efficient and cost effective deployment of clean energy and energy storage.

The ruling establishes new requirements to improve the accuracy and usefulness of ICA maps. These include requiring investor-owned utilities (IOUs) to:

  • Identify changes to enable the ICA results to aid customers seeking to add electric vehicle charging stations or reduce their use of natural gas in buildings,
  • Reduce how much data they redact from their ICA maps,
  • Improve their ICA data validation practices to avoid the presence of undetected errors, and
  • More broadly engage in a process of continuing improvements to ICA.

The CPUC’s action will make ICA more useful in showing the capacity of the grid to host new load, IREC said. Due to problems in initial ICA maps released by California’s IOUs, they previously were not useful for this purpose. In particular, IREC said the maps showed the distribution grid to be “significantly more constrained” in its ability to host new load than it actually is.

As part of the order, IOUs must make a filing describing the methodology, inputs, and assumptions of the load ICA; these will then be refined through workshops and public comment.

Another element of the decision related to data redaction. The CPUC had previously established redaction rules to protect customer information; however, earlier ICAs redacted more information than was necessary to protect customers’ privacy.

In particular, IREC said that San Diego Gas & Electric omitted the locations of substations. As a result, large portions of its map appeared blank because SDG&E redacted more than is allowed under the CPUC’s rules. The CPUC order confirmed that SDG&E redacted too much information and required IOUs to publish the location of transmission lines.

Finally, the CPUC ordered a number of other changes designed to make ICA results more useful. The order requires a process of continuing improvements, and establishes requirements for data validation.

Improvements include requiring better search and query functionality, publishing downloadable map files, updating user guides when map functionality changes, and displaying other useful information in the ICA maps.

The CPUC also required IOUs to file better data validation plans, and to hire an independent technical expert to review ICA data validation plans, identify best practices, and suggest improvements.


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