California Launches Pilot Program for “Notification-Only” Non-Export Energy Storage Interconnection
As regular readers of the IREC blog will know, interconnection—the process of connecting distributed energy projects to the grid—is a critically important issue for enabling the deployment of clean energy. IREC actively engages in regulatory reform processes in states around the country to help improve interconnection rules to reduce barriers to clean energy projects.
On June 4, the California Public Utilities Commission (CPUC) announced new updates to California’s interconnection rules. While the ruling addresses a number of issues, two, in particular, stand out for helping to streamline the interconnection process: 1) the creation of a “notification-only” interconnection process for certain energy storage projects (a first in the nation), and 2) steps to improve how utilities evaluate the risk of “unintentional islanding” in the interconnection process.
In this article, we delve into these two issues and why they are important.

Notification-Only Interconnection
The most notable change introduced in this regulatory proceeding is the establishment of a two-year pilot program for a “notification-only” interconnection process for certain small non-export energy storage projects. This means that qualifying projects by eligible installers would not have to submit an interconnection application or wait for approval from their local utility to interconnect.
As we discussed in a recent article for pv magazine, these kinds of non-export projects, which don’t send power back to the electric grid, have very limited grid impacts and thus merit simplified interconnection requirements.
While only a pilot program, and likely applicable to a relatively small pool of projects, this is a huge milestone for the simplification of the interconnection process and could create a model for other states to consider. This is essentially the first time that “notification only” interconnection has been implemented in the U.S.
While only a pilot program, and likely applicable to a relatively small pool of projects, this is a huge milestone for the simplification of the interconnection process and could create a model for other states to consider. This is essentially the first time that “notification only” interconnection has been implemented in the U.S.
Why did the Commission think this was important?
In its decision, the Commission noted that they “expect to experience an increased number of requests for these systems in the future,” and that the proposal, introduced by Tesla, “is a prudent solution since eligible projects are either exempt from or automatically pass all Rule 21 Initial Review screens used in the current interconnection application process.” The Commission was also motivated by the urgent need to enable customers to activate these systems before the Public Safety Power Shutoff events begin again this wildfire season.
What projects does this notification-only process apply to?
Only non-export energy storage projects below 30 kVA, meaning projects that do not send power to the electric grid, are eligible for this pilot. The decision identifies three specific eligible project types:
- a new non-export energy storage system (i.e., a standalone energy storage system),
- a new non-export energy storage system plus a new non-export solar system (i.e., solar and storage being installed together),
- or one new energy storage system plus any existing generation systems where the combined system is non-export.
There are several specific additional design requirements for eligible projects and a number of criteria that installers must meet to be able to participate in the program. For for the full list of design and eligibility requirements, interested individuals can see pages 14-19 of the decision.
What else?
Interestingly, in contrast to the typically lengthy process for implementing these kinds of changes, the Commission ruled that the state’s major utilities must make this option available to eligible customers no more than 45 days after the decision.
Utilities will gather data over the two years of the pilot project, which will inform a subsequent decision about whether to continue the notification-only approach, make modifications, or discontinue the program.
Utilities will also have the option to audit up to 20 percent of these projects to ensure that they are compliant with requirements. Projects found to be non-compliant will automatically have their “Permission To Operate” revoked and will need to go through the traditional interconnection application process to regain it (there are also consequences for the project developer).
Notification-only projects will still need to pay the full cost of the interconnection application fee ($800), which the California Solar & Storage Association (CALSSA) and other parties argued should be reduced given the reduced workload for utilities. However, the Commission notes that this will be revisited in the review of the pilot program.
Concept of renewable energy battery storage system in nature. 3d rendering
Improving Screening for Unintentional Islanding Risks
The commission also took steps to improve the process that utilities use to evaluate the risk of “unintentional islanding” posed by distributed energy resources (DER) projects seeking to connect to the grid. Islanding refers to conditions when DERs continue to provide power to a portion of the grid, despite the broader grid not having power.
Microgrids are a form of intentional islanding; they are designed to continue to serve power to an area even if the larger grid is not operational. However, if islanding occurs unintentionally, it can present a danger to utility workers and first responders who may not be aware that power is still flowing in certain areas during a power outage, among other issues.
Microgrids are a form of intentional islanding; they are designed to continue to serve power to an area even if the larger grid is not operational. However, if islanding occurs unintentionally, it can present a danger to utility workers and first responders who may not be aware that power is still flowing in certain areas during a power outage, among other issues.
Two of the three California investor-owned utilities, San Diego Gas & Electric and Southern California Edison, do not do additional screening for unintentional islanding when they evaluate interconnection requests. However, it is part of the evaluation criteria used by Pacific Gas and Electric and can result in significant upgrade costs for some projects.
The Commission made a variety of changes to how unintentional island risks are evaluated by PG&E. A more progressive screening approach will be used, which is expected to result in fewer projects being flagged as needing upgrades to avoid unintentional islanding. Additionally, interconnection customers whose projects are identified as needing upgrades, now have the option to hire an independent analyst to perform a formal study of unintentional islanding risk. These changes are expected to reduce the number of solar projects required to install expensive mitigations and also places more responsibility on machine generators to install anti-islanding mitigations.
Of particular interest to IREC, the Commission adopted our recommendation to also create a working group on unintentional islanding, which will work to evaluate solutions to islanding risks that could be implemented at the system (distribution grid) level rather than at the project level. This is a valuable step toward finding more efficient, and potentially more effective, ways to mitigate risks of unintentional islanding. The working group will tackle this issue over the next two years, at which point the Commission will revisit potential solutions. IREC is hopeful that this working group will be able to identify better methods for evaluating and mitigating islanding risks and that the outcomes of the process will also be helpful for other utilities and states.
The ruling also touched upon several other issues. The Commission acknowledged that further exploration of new approaches to allocating the cost of distribution upgrades would be beneficial; approved streamlined interconnection processes for zero net energy projects; and touched upon several other points.
The CPUC’s decisions, particularly regarding the notification-only interconnection process and anti-islanding issues, represent a step in the right direction to create a more efficient interconnection process for DERs.