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Arizona Public Service 400 N 5th Street Phoenix, AZ 85004 RE: AriSEIA Comments on the APS Interconnection Manual Draft Rev. 9.1 Dear APS Interconnection Team, The Arizona Solar Energy Industries Association (AriSEIA) appreciates the opportunity to provide comments on Arizona Public Service Company’s Interconnection Requirements Manual, Revision 9.1. These comments are intended to support clarity, consistency, and compliance with the Arizona Corporation Commission’s interconnection rules, particularly as they relate to Maximum Capacity, screening criteria, and the treatment of Active Power Limiting systems. AriSEIA’s overarching concerns fall into several categories. First, multiple sections of the Manual reference Nameplate Capacity where Maximum Capacity is required under Arizona Administrative Code R14-2-2615. Consistent and accurate use of the defined regulatory terms is essential to ensure uniform application of the screening process and to prevent inadvertent misclassification of generating facilities. Second, several provisions governing Active Power Limiting systems do not fully align with Arizona Corporation Commission requirements or with best practices used in other jurisdictions. These include scope limitations, terminology inconsistencies, and restrictions that would unnecessarily limit non-parallel operating modes that are widely expected to become more common as solar and storage penetration increases. Third, certain protection and monitoring requirements would benefit from additional specificity to improve predictability for both developers and reviewers. In particular, clarification of Minimum Power Protection settings and the definition of the Relative Generating Facility Rating will help ensure consistent implementation across projects. A detailed list of recommended revisions is attached. These recommendations include requested edits to sections 8.1, 8.3, 10.4, 12.2, and related protection and control provisions. Each recommended change is tied either to Arizona Corporation Commission rule requirements or to accepted technical standards used in other jurisdictions. AriSEIA appreciates APS’s attention to these issues and remains committed to constructive engagement to support an interconnection process that is efficient, transparent, and compliant with state requirements. Please do not hesitate to contact us with any questions. Sincerely, /s/ Autumn T. Johnson Executive Director AriSEIA (520) 240-4757 [email protected] 
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May 9, 2025 Arizona Public Service 400 N 5th Street Phoenix, AZ 85004 RE: AriSEIA Comments on the APS Interconnection Manual Draft Rev. 10 Dear APS Interconnection Team, As agreed, we are submitting this summary of the five specific handbook topics of present concern to AriSEIA in advance of APS filing the revised manual with the Commission. We would like to reach resolution prior to filing, if possible. Section 8.2, Utility Disconnect Supply side connections of non-residential systems and the use of the National Electrical Code (NEC)-required external Fused Service Disconnect as the approved Utility Disconnect – Rev. 9.0 to the manual allows the Fused Service Disconnects for customer GF supply side connections in section 8.2(A) to be used as the Utility Disconnect. This language was explicitly negotiated and agreed to by APS during the 2021-2022 manual revisions and was approved by the Commission in November 2022. The use of a Fused Service Disconnect also as a Utility Disconnect is ubiquitous across the country, with those requiring redundant disconnects being the exception rather than the rule. Notably, Tucson Electric Power (TEP) allows the Fused Service Disconnect to serve as the DG Disconnect (see TEP’s Interconnection Manual for Distributed Generation, Section 9.2.1.b) as does Salt River Project (see SRP’s DER Technical Requirements, Section 2.8.1.b). All California utilities also allow for Fused Service Disconnects to serve as the Utility Disconnect – see PG&E’s Supply Side Interconnection Requirements for reference. An additional Utility Disconnect for line-side/supply-side taps beyond a Fused Service Disconnect per NEC is redundant, arbitrary, and a costly requirement, and ARISEIA objects to the Rev. 10 proposed language that limits the dual-purpose potential of Fused Service Disconnects to residential single-phase systems. Moreover, the unilateral and retroactive enforcement of changes to the approved APS Interconnection Manual language, which were negotiated in good faith and approved by the Commission, is a significant oversight by APS management and has led to countless thousands of dollars of additional cost burdens on its customers since approval in 2022. APS staff should immediately adhere to the original intent of the language as previously approved, and attached to these comments are an exhibit demonstrating the written and clear intent to modify the language to remove unnecessary equipment from customer-owned GF installations (See Comment 3 and Response). Furthermore, the verbal comments offered by APS that non-residential GF installations have greater public access than residential systems is specious, as requiring separate fused disconnects and utility disconnects results in double the number of devices the public can access and operate. Locking provisions are readily accessible for both residential and nonresidential versions of Fused Service Disconnects and are a simple solution to the otherwise costly approach administered by APS requiring an additional Utility Disconnect. The NEC is the governing standard for the safe installation of electrical wiring and equipment in the United States. It is fundamentally a safety standard. Its primary purpose is to protect people and property from electrical hazards by preventing electrical fires, reducing risk of shock, setting clear installation standards, ensuring safe use of new technologies, promoting uniformity, and setting guidelines for inspections and permits. The NEC does not require a second utility disconnect for commercial-scale solar projects that are interconnected on the utility side of a customer’s meter; the only equipment required for safety purposes is a single fused service disconnect in accordance with NEC 2017 230.82(6), 705.12(A), and 705.31. Therefore, an additional Utility Disconnect is not necessary for the safe operation of a solar photovoltaic system, and APS should align with its state and national utility counterparts by removing this requirement. Section 9.2, Production Metering Requirements APS requires production metering for Static Inverter based Energy Storage Systems unless they are co-located with a PV system and properly configured, or unless the customer agrees to provide equivalent data hourly. AriSEIA has consistently objected to metering battery discharge, including Rev. 9 of the manual which limited the requirement to standalone battery systems. Note that an Energy Storage System does not produce power at all, so the need for a “production meter” is nonsensical. This requirement will prove even more excessive as APS continues to progress toward adopting electric vehicles as an additional means of balancing the load on the electric grid. Meter disconnects further exacerbate the cost of this requirement. Short of an optional utility program to monitor or dispatch customer battery discharge and compensate customers, the customer’s site meter is sufficient to support the financial transaction for exported energy from battery systems. Utilities do not need real time measurement of battery usage any more than for sub-metered loads turned on or off. AriSEIA recommends that section (C) be removed in its entirety. Section 10.4, Inadvertent Export or Active Power-Limiting Protection Requirements The second sentence says “For GF’s with kVA rating greater than POI kVA rating protection requirements…” This sentence is missing a limiting kVA rating value separate from the POI rating. The value should be above the Commission limits that apply to Inadvertent Export Systems considered Fast Track. Section 4.1, Separate System The revision to include all Non-exporting systems as separate systems needs adjustments. Unlike backup systems, they do serve customer loads in parallel to the utility system on a continuous basis. The language confuses the issue of needing a Transfer Switch, which only applies to those Non-exporting systems incorporating a Backup System operating mode. The non-exporting feature can be provided by control systems and/or relays instead of a transfer scheme. Other sections deal with Non-exporting systems and appropriate exemptions from requirements for exporting systems. AriSEIA suggests limiting the Separate System definition to Non-exporting systems that can function as a Backup system. The new provisions of section 4.1(D) are appropriate for Non-Exporting systems regardless of the Backup capability, which should be clarified as part of the discussion. Section 2, Definitions The new definition for Point of Service describes the identical location as the current definition for Point of Interconnection, except without a GF operating in parallel. Is it needed in the Interconnection Manual? Also, the current definition claims the POI is also known as the Point of Common Coupling. In the industry, the POCC refers to the connection that could be at a different location than customer service equipment, such as a utility transformer. Even in the absence of a deregulated generation market, a change to this language could be useful for developers of APS distributed solar systems and future Community Solar systems. Thank you for considering these comments. We would appreciate a response before filing the manual revision. Sincerely, /s/ Autumn T. Johnson Executive Director AriSEIA (520) 240-4757 [email protected]
Arizona Corporation Commission
1200 W. Washington Street Phoenix, AZ 85007 Re: Exceptions to APS Interconnection Manual, Docket E-01345A-20-0152 Madam Chair and Commissioners, The Arizona Solar Energy Industries Association (AriSEIA) hereby files its Exceptions to Staff’s Memorandum and Proposed Order filed on September 29th, 2022. AriSEIA appreciates Staff’s efforts in reviewing Arizona Public Service’s (APS) Draft Interconnection Manual (the “Manual”). AriSEIA believes that the Order should be amended to incorporate several outstanding changes that are important to simplifying the interconnection process and are justified based on established technology performance across the globe and in other leading U.S. markets. The following Exceptions detail what changes must be made so that APS customers can further benefit from distributed generation, which will play a critical role in modernization of the grid. As further background, AriSEIA participated in extensive review and discussion of the Manual with Staff and APS personnel throughout 2022, and we have filed comments in this docket and submitted written feedback to both APS and Staff on outstanding issues. During the deliberation on the Commission’s Interconnection Rulemaking, we expressed our concern that there are many utility requirements that unnecessarily inflate costs while adding unnecessary time and complexity to the process for interconnecting distributed generation systems in APS territory. The Exceptions detailed herein remain in the spirit of this prior notion. I. Production Meters for Energy Storage Systems (Section 9.2(C) and (D) of the Manual) Section 9.2.(C) of the Manual states that a customer must provide Production Metering for any Static Inverter based Energy Storage System (ESS) (i.e., battery backup system). In addition to requiring Production Metering, Section 9.2.(D) further requires that “[c]ustomer must provide a suitable visible open disconnecting means […] to electrically isolate any CT rated meter from all potential sources of power.” AriSEIA strongly believes that Production Metering requirements and, by extension, additional disconnecting means, are unreasonable and unwarranted for any residential or commercial customer-owned ESS designed to provide value strictly “behind the meter.” A solar system Production Meter captures all of its production. When discharging, backup batteries do not create new energy production. Furthermore, Tucson Electric Power (TEP) already acknowledged these arguments and agreed to remove their requirement for ESS Production Metering in the latest version of their Interconnection Manual filed and approved earlier this year. A proposed amendment making this modification is attached below as Attachment A, AriSEIA Proposed Amendment No. 1. II. Production Meters for All Generating Facilities (Section 9 of the Manual) In general, and as an extension of our comments above, AriSEIA contends that Production Meters for any customer-owned Generating Facility are unwarranted in the post-incentive era, which included Performance-Based Incentives (PBI) and Upfront Incentives in exchange for ownership of a customer’s Renewable Energy Credits (REC). The applicable requirements of Section 9 are costly and burdensome when considering that distributed generation industries are disproportionately impacted by supply chain and inflation conditions to the extent that project viability is seriously impacted. Meanwhile, it is entirely feasible for regulators and utility companies alike to estimate solar production based on the system details included in Interconnection Applications, and we contend that such estimates are sufficient in lieu of Production Metering. A proposed amendment making this modification is attached below as Attachment B, AriSEIA Proposed Amendment No. 2. III. Ground Fault Detection Requirements for Class III Systems (Section 10.2(B)(2)e. and (3)e. of the Manual) Section 10.2(B)(2)e and (3)e. states that systems in the applicable size range may require the addition of ground fault detectors in cases where the Generating Facility parallels the utility through a transformer with ungrounded configurations (float wye or delta). Utility systems must already include ground fault detection and protection with or without the presence of customer-owned Generating Facilities. In addition, Screen B of Appendix B: Interconnection Application Screens validates whether a Generating Facility’s ground fault current contributions are low enough to be safe, and any system passing this Screen should, therefore, be accommodated through existing utility equipment. At a minimum, AriSEIA contends that a clear exemption from additional ground fault detection equipment must exist for any systems which pass Screen B, as well as Non-Exporting Systems and Inadvertent Export Systems of 20 kW or less. A proposed amendment making this modification is attached below as Attachment C, AriSEIA Proposed Amendment No. 3. IV. Study Feed (Appendix C of the Manual) The Commission’s Rules for Interconnection established that fees are allowed for utility studies “if a tariff containing such a fee for the Utility has been approved by the Commission.” Both APS and TEP include written handbook provisions which require specific fee deposit payments and provide for refunds through subsequent adjustment to the actual study costs (though costs are not defined). AriSEIA members consistently experience disproportionately high utility study deposits relative to the actual charges that are attributable to the work involved. Refunds are issued after extended periods of time (often in excess of 12 months) and represent a consistent majority of the original deposits that were made. Considering the excessive study deposits that the industry continues to grapple with, AriSEIA contends that the deposit amounts, and philosophy on study deposits, be revised in accordance with the following comments, and should be submitted to the Commission for approval:
A proposed amendment making this modification is attached below as Attachment D, AriSEIA Proposed Amendment No. 4. V. Rate Schedules Applicable to Distributed Generation, System Size Limiting Factors (Appendix D of the Manual) Under System Size Limiting Factors in Appendix D of the Manual, item 1.b., the methodology for calculating the maximum system size for non-residential DG systems is presented as “125% of connected load for its meter, where connected load is defined as the maximum demand divided by 0.6.” Item 2.a. further defines that the “connected load is measured in AC.” Based on AriSEIA discussions with Staff and APS, and written redlines from APS, AriSEIA notes that the intent of the definition in 2.a. was to establish that the system size is measured in AC, rather than “connected load,” which would translate to the output of the methodology in 1.b. being a non-residential DG maximum system size measured in kW AC. A proposed amendment making this modification is attached below as Attachment E, AriSEIA Proposed Amendment No. 5. VI. Conclusion Because these manuals are iterative, the utilities should establish a stakeholder process to discuss developing issues with the manuals and technological change. We respectfully request the Commission direct APS to file a revised Manual with the amendments attached below by November 15, 2022, to be effective immediately upon filing. Thank you for considering these comments meant to improve the compliance of the APS Manual with the spirit and letter of the Commission’s Interconnection Rules. Arizona Corporation Commission
1200 W. Washington Street Phoenix, AZ 85007 Re: APS Interconnection Manual, Docket E-01345A-20-0152 Madam Chair and Commissioners, This item is scheduled for the Staff Meeting on August 16, 2022, as number 11. The Arizona Solar Energy Industries Association (AriSEIA) has reviewed the Arizona Public Service (APS) Interconnection Requirements for Distributed Generation Rev. 9.0 dated May 6, 2022, and as amended in redlined versions from APS on July 20, 2022 and August 10, 2022 (the “Manual”). We have filed comments in this docket, met with APS and Commission Staff several times, and have submitted written feedback to both APS and Staff on outstanding issues. During the deliberation on the Commission’s Interconnection Rulemaking, we expressed our concern that there are many utility requirements that unnecessarily inflate cost while adding time and complexity to the process for interconnecting distributed generation systems in APS territory. Unfortunately, the July 24, 2020, Rev. 8.5 Manual shown on the APS website is the Manual currently being utilized by APS, despite numerous elements that make interconnecting distributed generation needlessly costly for consumers. In fact, in some respects, APS ignores the Commission’s Interconnection Rules. The usage of this older version of the manual is very detrimental to our member companies. This stands in stark contrast to Tucson Electric Power (TEP) who adjusted their interconnection requirements with each revision of their handbook as issues were identified and eliminated during the stakeholder process. The APS Manual revisions to date make multiple changes as a result of stakeholder engagement that address issues that continue to impact the cost, size, and schedules of projects over two and a half years after the Commission’s Interconnection Rules became effective. We respectfully request the Commission direct APS to file a revised Manual no later than August 31, 2022 and to utilize that version until a final vote by the Commission. Given the significant delay in the finalization of the Manual, we request this matter be noticed for a final vote on the October Open Meeting agenda. Thank you for considering these comments meant to improve the compliance of the APS document with the spirit and letter of the Commission’s Interconnection Rules. Respectfully, Autumn Johnson Executive Director AriSEIA 520-240-4757 [email protected] Mark Holohan Board of Directors AriSEIA 602-339-8274 [email protected] AriSEIA Negotiated TEP Revised Distributed Generation Interconnection Manual Approved by ACC6/30/2022 Commissioners approved Tucson Electric Power Company’s (TEP) revised Distributed Generation Interconnection Manual. The creation of these manuals was required following the Commission passing rules dealing with the interconnection of distributed generation facilities. TEP’s manual lays out technical and safety requirements that customers within its service territory must follow when interconnecting a distributed generation system, such as residential and commercial solar projects, to the existing grid. The manual is meant to create a standardization process for customers.
TEP’s manual was initially approved at the Commission’s February 2022 Open Meeting, however, following the passage of AriSEIA proposed amendments at that meeting, a revision to the manual was necessary. After several meetings between AriSEIA, TEP, and ACC Staff, the manual was revised to include information regarding Meter Socket Adapters (MSA), detailing their use for generating facilities. The manual was updated to better preserve the Super-Fast Track and Fast Track designations, allowing for faster review tracks for qualified projects. The revised manual also clarifies study cost fees customers are responsible for prior to beginning any study. TEP’s revised manual does not prematurely require inverters to comply with the IEEE sections that are not yet developed or for which equipment is not yet capable of compliance. Further, the manual modified its requirements around transfer trip infrastructure so as not to be overly burdensome, thereby reducing costs for large installations. Finally, the revised manual includes an additional section that provides a list of scenarios meriting an extension of time. All documents related to this agenda item can be found in the Corporation Commission’s online docket at https://edocket.azcc.gov and entering docket number E-01933A-20-0116.  AriSEIA joined a letter with several solar companies asking the Arizona Corporation Commission to direct its Staff to issue a Proposed Order on APS' outstanding interconnection manual, so that the manual can be voted on as soon as the May Open Meeting. The APS manual was filed and has been awaiting review by the Commission for years. This follows a letter by AriSEIA asking for a vote on this matter last year. A status update on this matter is on the agenda for the April Open Meeting, which is this week.
AriSEIA filed extensive comments and amendments on Friday, February 4, 2022 with the Arizona Corporation Commission (ACC) calling for changes with Tucson Electric Power (TEP)'s interconnection manual. Specifically, AriSEIA proposed changes to the treatment of Meter Socket Adapters; Construction Timelines; Fast Track, Non-Exporting, and Inadvertent Export Systems; and Fees and Costs charged to customers. This matter is on the agenda for the ACC's February Open Meeting on February 8, 2022. You can find the agenda and watch the meeting here.
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The Arizona Solar Energy Industries Association (AriSEIA) is a 501(c)(6) non-profit trade association representing the solar, storage, and electrification industry, solar-friendly businesses, and others interested in advancing complementary technologies in Arizona. The group's focus is on education, professionalism, and promotion of public policies that support deployment of solar, storage, and electrification technologies and renewable energy job growth and creation. |
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