FOR IMMEDIATE RELEASE

Contact:
Autumn Johnson
(520) 240-4757
[email protected]

Phoenix, AZ - Today, the Arizona Corporation Commission (ACC) voted 4-1 to approve Arizona Public Service's (APS) Virtual Power Plant (VPP) pilot program.  AriSEIA proposed that APS adopt a VPP in its 2022 rate case. The ACC voted on February 22, 2024 to proceed with a VPP as a pilot program and ordered APS to file a plan of administration to implement that program. That implementation plan was voted on today and passed 4-1 with only Vice Chairman Myers voting no.

A virtual power plant allows a utility to aggregate customer owned devices, like batteries, to provide capacity back to the grid. APS' proposal is a pay-for-performance model in which customers are paid only when they provide capacity to the grid and they are paid a rate less than that of comparable wholesale purchases, saving all rate payers money.

"Virtual power plants are a win win for customers and the grid. These batteries are paid for with private capital and are already interconnected and ready for use today. This program will help APS meet the growing demand for electricity in Arizona," said Autumn Johnson, Executive Director of AriSEIA. "Trico already has a VPP and Salt River Project (SRP) just voted to implement one this year. Tucson Electric Power (TEP) plans to propose one in its next rate case. Arizona is moving in the right direction."

VPPs are deployed all over the country. There are more than 500 in the US and their capacity is expected to top 60 GW by 2030. According to the US Department of Energy, “VPPs are among the critical solutions to meet the pressing challenges the grid faces today and in the near term to keep electricity rates affordable while maintaining grid reliability and resilience.”[1] According to Brattle, VPPs could save US utilities $15-35 billion in capacity investment over ten years.[2]

The full docket can be found here.

About AriSEIA

AriSEIA is the leading voice of the solar industry in Arizona, dedicated to advancing solar energy through advocacy, education, and collaboration. With a commitment to promoting sustainable energy solutions, AriSEIA serves as a catalyst for the growth and development of Arizona's solar industry.

[1] US DOE, Pathways to Commercial Liftoff: Virtual Power Plants 2025 Update, January 2025, available here https://liftoff.energy.gov/wp-content/uploads/2025/01/LIFTOFF_DOE_VirtualPowerPlants2025Update.pdf. 

[2] Brattle, Real Reliability: The Value of Virtual Power, May 2023, available here https://www.brattle.com/wp-content/uploads/2023/04/Real-Reliability-The-Value-of-Virtual-Power_5.3.2023.pdf. 

Arizona Corporation Commission
1200 W. Washington Street
Phoenix, AZ 85007
 
RE: Please approve the APS Virtual Power Plant (BYOD) Pilot Program, Docket No. E-01345A-22-0144; Exceptions
 
Dear Chairman and Commissioners,
 
This issue was thoroughly litigated in the last Arizona Public Service (APS) rate case. APS conducted a robust stakeholder process as ordered by the Commission. AriSEIA recommends adoption of the Plan of Administration (POA) as filed.
 
The Grid Needs More Capacity
APS is predicting unprecedented load growth over the next decade. To meet this rising need, the utility must aggressively add capacity which, if not done thoughtfully, will put dramatic upward pressure on rates. One way to mitigate that upward rate pressure is to avoid direct utility investments where possible and to leverage customer owned assets to provide services that would otherwise require utility investment and risk increasing ratepayer costs. To this end, the Commission ordered APS to implement the money-saving Bring Your Own Device (BYOD) program (also known as a virtual power plant (VPP)) which uses customer owned batteries to meet peak demand. The evidence in the rate case found that such a program could give APS access to batteries at a cost well below the cost of utility owned storage or market purchases.

The Company has projected more than 4,000 MW of new capacity need over the following decade, and its integrated resource plan (IRP) shows that it will be procuring copious amounts of centralized generation and battery storage. APS’ 2024 all source request for proposals (ASRFP) sought at least an additional 2,000 MW of resources by 2030.[1]

Residential Batteries Can Provide Capacity
The Commission has been discussing this concept since at least 2020. In Decision No. 77855, the Commission ordered APS to “permit the aggregation of distributed demand-side resources [DDSR]… and provide compensation for the value each distributed demand-side resource provides, including, but not limited to, compensation for capacity, demand reduction, load shifting, locational value, voltage support, ancillary and grid services…”[2] In Decision No. 78165, the Commission ordered APS to file a DDSR tariff by May 1, 2022.[3] More than a dozen stakeholder meetings were held just in preparation to the filing of the DDSR tariff.[4] Once the tariff was filed, an entirely new docket was opened; workshops were held; national labs were engaged. That docket resulted in an additional year of work that resulted in the Commission finding APS did not go far enough and directing APS to issue a new RFP for the DDSR aggregation tariff.[5]
Also in 2020, Commission Staff recommended approval of APS’ original battery pilot program, which had an upfront incentive for installing batteries. Staff said, “a tariff that compensates customers for the specific benefit their systems bring to the grid can also be beneficial and in the public interest.”[6] Staff characterized such a program as a “forward-looking policy that can benefit all APS ratepayers.”[7] When APS first proposed this pilot, it stated this original pilot would “inform a future potential ‘pay-for-performance’ shared storage program and system planning to ensure continued reliability for APS customers.”[8]

APS sought to expand the original battery pilot, which was fully subscribed by January of 2023.[9] APS proposed expanding the battery pilot program in its amended 2023 Demand Side Management (DSM) plan. APS stated, “reallocating DSM budget to support expansion of the Residential Battery Pilot-an already-successful program that APS believes represents the best path forward to achieve the Commission's DDSR goals.”[10] The Commission has not voted on the APS 2023 DSM plan or its 2024 plan in which it also requested expanding the program.[11]

APS subsequently closed its battery pilot program because the Commission voted to pursue this VPP program instead in Decision No. 79293. At the February 22, 2024 open meeting in which the 2022 rate case was voted on, Vice Chairman Myers specifically asked Staff and the administrative law judge about their opinions on moving forward with the VPP program. Commission Staff said they have “no concerns moving forward” with the VPP program as was directed in the Recommended Opinion and Order.[12] Judge Harpring said the VPP “would present an opportunity that APS currently lacks that could be a lot more meaningful than APS’ battery pilot” and “I think this is an opportunity. APS needs a lot of dischargeable resources. This would provide a new dischargeable resource and I see that as a positive.”[13]

Denying the POA would eliminate all battery pilot programs at APS and would set Arizona back more than five years. That is not an efficient use of taxpayer dollars as the Commission has been pursuing this since 2020 or ratepayer dollars since APS has been working to aggregate demand side resources also since 2020. Another rate case would result in an unnecessary delay of at least two more years.

There are more than 500 VPP programs in the US.[14] By 2030, VPPs could reduce peak demand in the US by 60 GW. By 2050, VPPs could grow to more than 200 GW nationwide.[15] According to Brattle, VPPs could save US utilities $15-35 billion in capacity investment over ten years.[16] According to the US Department of Energy, “VPPs are among the critical solutions to meet the pressing challenges the grid faces today and in the near term to keep electricity rates affordable while maintaining grid reliability and resilience.”[17] Salt River Project (SRP) just committed to develop a VPP program by the end of 2025.[18]

Residential Batteries Add Capacity For Less Than Market Purchases
APS provided the quantity and price of its wholesale market purchases from 2018-2022 in the rate case.[19] An analysis of this data shows that the Company routinely paid in excess of $200/MWh for market purchases, with occasional purchases in excess of $1,000/MWh.  AriSEIA/SEIA’s analysis showed that the average weekday market purchase cost between 2019 and 2022 was over $100/MWh between 5 PM and 9 PM, the exact hours the VPP program would target.[20] 

But if one looks at the actual highest-cost purchases, the avoided energy potential is much higher. AriSEIA/SEIA determined the 500 highest cost hourly purchases throughout the year and then analyzed the purchases that fell in the core summer months of June to September from 2018 through 2022.[21] 

Even in 2019, which was an outlier in terms of the low quantity of high-cost market energy purchases, the average purchase during the high-cost hours was nearly $400/MWh. In 2021 and 2022 (and likely 2023), the price and quantity of high-cost purchases surged, with the average high-cost hour moving north of $800/MWh. 

Additionally, at $110/kW per year, the VPP program is less expensive that the cost of utility scale battery storage. The evidence in the hearing showed that the revenue requirement for APS-owned utility-scale batteries costs ratepayers $208/kW per year.[22] AriSEIA originally proposed $150/kW. The valuation in the POA is the result of a compromise derived out of the Commission ordered stakeholder process in Decision No. 79293.

Please Adopt the APS POA
In Staff’s Memorandum, they correctly assert the numerous benefits that this program can provide to the grid and they correctly state that all of these numerous benefits were discussed at length during the six month stakeholder process, which led to the creation of the POA. It is incongruent to argue that APS does not consider enough of the benefits which would “lower the net cost of the BYOD Program” and “increase the availability of customer incentives” while also stating that the program presents a possible cost shift.[23] Making the program a pilot capped at 5,000 customers was a compromise that the Commission already voted on in Decision No. 79293. Changes to the size of the program are not part of the Commission order to APS or Staff and are outside the scope of the POA. Additionally, the costs of the program are already factored into the per-kW valuation. The payments to participating customers are already reduced to cover the costs of the program. Further, while Staff expresses concerns of a cost shift, they also argue that APS should rate base the VPP program, which would allow APS to collect a return on the VPP program, which would increase costs for everyone.

As mentioned above, APS’ first battery pilot was fully subscribed. As of January 31, 2025, APS had more than 4,195 customers with batteries and another 1,250 were in the interconnection pipeline. Given the increase in electricity rates and the decrease in the RCP, most installations will soon be solar plus storage. Further, it is the installers who obtain customer enrollment, not APS or EnergyHub. The installers already have direct relationships with qualifying customers and have a natural incentive to educate customers as to the program. APS’ Cool Rewards program currently has 95,000 enrolled customers, capable of conserving 160 MW of energy.[24] The potential for a battery program is significant.
As was directed in Decision No. 79293, APS thoroughly considered the kW versus kWh issue, which was resolved in favor of a program design with a $/kW payment structure. We have no recollection of Staff ever raising this issue in the stakeholder process. As a capacity resource, which is the point of the program, kW are the appropriate metric. This was also discussed at length in the rate case testimony.

Staff states that, “given the increasing demand for electricity in Arizona, Staff recognizes the importance of leveraging existing capacity resources and supports the advancement of technologies.”[25] We agree. According to APS, “APS resource planners expect peak customer demand to grow to more than 13,000 MW by 2038. For perspective, it took APS 140 years to reach 8,200 MW of peak demand, and customer needs will increase by 60% in only 14 years.”[26] The Commission has been discussing this concept for five years and this exact program for two years. Additional delay is unwarranted and needlessly limits capacity resources that are already available today at a time when we are experiencing significant load growth at a price less expensive than the alternative.

As Staff correctly points out “APS was ordered to meet with other interested parties to collaboratively reach an agreement on the language of the BYOD POA.”[27] And against all odds, APS has done just that. Please approve the POA as drafted. AriSEIA has attached AriSEIA Proposed Amendment 1 to modify Staff’s draft order to approve the POA.
​
Respectfully,

Autumn T. Johnson
Executive Director
AriSEIA 
(520) 240-4757
[email protected]

[1] APS 2024 ASRFP, available here https://www.aps.com/en/About/Our-Company/Doing-Business-with-Us/Resource-Planning/Request-for-Proposals.

[2] ACC Decision No. 77855, Docket No. E-01345A-19-0148, available here https://docket.images.azcc.gov/0000202797.pdf?i=1741200024102.

[3] ACC Decision No. 78165, Docket No. E-01345A-19-0148, available here https://docket.images.azcc.gov/0000204280.pdf?i=1741200631832.

[4] APS DDSR Tariff, June 1, 2022, Docket No. E-01345A-22-0143, available here https://docket.images.azcc.gov/E000019505.pdf?i=1741200030297.

[5] ACC Decision No. 78878, March 16, 2023, Docket No. E-01345A-22-0143, available here https://docket.images.azcc.gov/0000208710.pdf?i=1741200030297.

[6] ACC Decision No. 77762, Docket No. E-01345A-19-0148, available here https://docket.images.azcc.gov/0000202207.pdf?i=1741200977874.

[7] Id.

[8] APS Supplemental to the 2020 RES Plan, August 26, 2020, Docket No. E-01345A-19-0148, available here https://docket.images.azcc.gov/E000008576.pdf?i=1741203415780.

[9] APS 2023 Demand Side Management Annual Progress Report, March 1, 2024, Docket No. E-00000U-18-0055, available here https://docket.images.azcc.gov/E000034300.pdf?i=1741300652460.

[10] APS Amended 2023 DSM Implementation Plan, May 31, 2023, Docket No. E-01345A-22-0066, available here https://docket.images.azcc.gov/E000027360.pdf?i=1741300107475.

[11] APS 2024 DSM Plan, November 30, 2023, Docket No. E-01345A-23-0088, available here https://docket.images.azcc.gov/E000032472.pdf?i=1741374160495.

[12] February 22, 2024 Open Meeting at 7:21:00.

[13] Id.

[14] Utility Dive, US VPPs Can Meet Summer Demand Peaks Faster, Cheaper Than New Generation and Transmission, July 10, 2024, available here https://www.utilitydive.com/news/us-vpps-can-meet-summer-demand-peaks-faster-cheaper-than-new-generation-an/721024/.

[15] RMI, Virtual Power Plants, Real Benefits, January 2023, available here https://rmi.org/insight/virtual-power-plants-real-benefits/. Attachment A

[16] Brattle, Real Reliability: The Value of Virtual Power, May 2023, available here https://www.brattle.com/wp-content/uploads/2023/04/Real-Reliability-The-Value-of-Virtual-Power_5.3.2023.pdf. Attachment B

[17] US DOE, Pathways to Commercial Liftoff: Virtual Power Plants 2025 Update, January 2025, available here https://liftoff.energy.gov/wp-content/uploads/2025/01/LIFTOFF_DOE_VirtualPowerPlants2025Update.pdf. Attachment C

[18] SRP, Board of Directors Approves Pricing Proposal, February 27, 2025, available here https://media.srpnet.com/srp-board-of-directors-approves-pricing-proposal/.

[19] AriSEIA 4.03_ExcelAPS22RC03362_Hourly Market Purchases 2018-2022

[20] Lucas Direct at 59.

[21] This is twice as many as are allowed in the BYOD program, which authorizes 60 event days with events up to 4 hours.

[22] See Kevin Lucas in hearing test. Sept. 1, 2023 at 00:04:31.

[23] Utilities Division Memorandum, February 26, 2025, Docket No. E-01345A-22-0144, available here https://docket.images.azcc.gov/E000041768.pdf.

[24] APS Customers Served with Reliable Power During Record-Breaking Heat, October 7, 2024, available here https://www.aps.com/en/About/Our-Company/Newsroom/Articles/APS_Customers_Served_With_Reliable_Power_During_Record-Breaking_Heat#:~:text=APS%20Cool%20Rewards%20acts%20like,small%20power%20plant%20would%20produce.

[25] Utilities Division Memorandum, February 26, 2025, Docket No. E-01345A-22-0144, available here https://docket.images.azcc.gov/E000041768.pdf.

[26] APS Secures its Largest-Ever Energy Supply to Reliably Serve Customers, November 20, 2024, available here https://www.aps.com/en/About/Our-Company/Newsroom/Articles/APS_Secures_its_Largest-Ever_Energy_Supply_to_Reliably_Serve_Customers#:~:text=APS%20resource%20planners%20expect%20peak,is%20conducting%20a%202024%20ASRFP.

[27] Utilities Division Memorandum, February 26, 2025, Docket No. E-01345A-22-0144, available here https://docket.images.azcc.gov/E000041768.pdf.

Salt River Project
1500 N. Mill Avenue
Tempe, AZ 85288
 RE: 2025 Pricing Proceeding Recommendations
 
Mr. President, Board Members, and Staff,
 
The Arizona Solar Energy Industries Association (AriSEIA) is the solar, storage, and electrification trade association for the State of Arizona. We advocate for pro renewables policies at every level of government. AriSEIA does not speak for or represent a single company. We represent nearly 100 companies in the State and we advocate for policies that we think are beneficial for the industry and the grid and best serve the public interest to the greatest extent possible.
 
As such, we agree with most of the proposals made by the other organizations, namely Southwest Energy Efficiency Project (SWEEP), Vote Solar, Wildfire, Arizona PIRG, Western Resource Advocates, and Sierra Club on February 6th. We also support many of the points made by Mr. Neil. We agree with an evidenced based approach to policy and ratemaking. We do not support or endorse comments or proposals that impede the clean energy transition, either by individual commenters or individual companies. Batteries are an essential and integral component to increased renewables on the grid, both at the distributed and utility scale levels. Misinformation about the safety or efficacy of batteries is unhelpful and shortsighted and we encourage the board and management to disregard such comments and proposals.
 
Correcting Battery Misinformation
While China is currently the world's leading manufacturer of battery cells, a diversified supply chain outside of China is rapidly developing, including manufacturing here in the U.S. The risk of China-only sourcing diminishes by the day.
 
Residential batteries do not fail at high rates; they work well when properly installed. Very few residential batteries fail. Like any other mechanical or chemical device, batteries degrade over time. The manufacturer maps, specifies, discloses, and guarantees this degradation. After 10 years, typical home batteries are guaranteed to still produce 70% (on average) of their original rated capacity. Capable installers consider this degradation when modeling system performance and expected savings and discuss these factors with their clients. Every home is different, uses different amounts of energy, and has different load profiles from other houses. Ethical, competent solar installers study the complexities of home batteries and design the best system for the home, the homeowner's usage, and savings goals. Batteries are often used to achieve these goals, and when designed and installed correctly, they will provide many years of reliable operation and savings.
 
There are very few fire risks associated with modern batteries. Manufacturers have incorporated numerous safety features designed to ensure safety, and data shows very few issues. Additionally, the best practice in Arizona is to install the battery inside of a home, in a garage or utility room, and not outdoors. Home batteries are widely available and can be ordered, delivered, and installed today. Out of half a dozen popular battery manufacturers, only one is experiencing supply issues.
  
Virtual Power Plants
Distributed batteries allow individual ratepayers to reduce their electric bills and increase their resiliency in the event of a power outage, while also benefiting the utility and other ratepayers, by providing valuable capacity when the grid needs it most. Valuing that capacity sends a price signal to a ratepayer who has used their own capital to install a battery to provide the stored energy to the grid, instead of their own home, when there is strain on the grid. This is a supply virtual power plant (VPP). SRP can call an event on a hot August afternoon and thousands of homeowners can respond by allowing SRP to use their batteries, instead of them using the stored power themselves.
 
According to the U.S. Department of Energy, there is currently 30-60 GW of VPP capacity on the grid today, but that amount needs to triple by 2030.[1] Arizona Public Service (APS) is in the process of adopting a VPP modeled off of AriSEIA’s proposal, which is derived from a very successful VPP program called ConnectedSolutions. Our proposal is a pay for performance only model that allows the utility to call up to 60 events in the summer season for up to three hours. A third party aggregator operates the program just like a smart thermostat program. Participants can lock in their rate for five years. While we understand that actual adoption of a VPP program within this pricing proceeding may not be possible, we recommend the Board direct management to engage with AriSEIA to develop a program to bring to the board for consideration by the end of the year.
  
Time of Use
64% of SRP’s customers are not on a time of use rate and 95% of SRP’s customers can opt out of a time of use rate. Only 5% of SRP’s customers are solar customers and, yet, they are the only customers required to be on a time of use rate. All customers should have the same rate plan options and all customers should be defaulted onto a time of use rate. Contrary to the comments of the board consultant, no one has argued for 100% participation on the time of use rates, but it should be the majority of customers and customers should have to opt out, rather than opt in. No current time of use customers should be defaulted to non-time of use rates in 2029. They should instead be defaulted to E-28. The differential between the on peak and off peak rates should be roughly 3:1 and that differential should be between on and off peak, not on and super off peak. The on peak time of use window should be three hours to maximize participation.
 
We recommend that E-16 and E-28 have the same on peak period. To alleviate management’s concern about the shifting on peak window and the need to cover more than just 3 hours, we recommend customers have the option of one of two staggard on peak windows. We recommend a 4-7pm on peak option and a 6-9pm on peak option. This alleviates strain on the grid, allows families to select which plan works best for their schedule, and does not penalize solar owners.
 
We also recommend that the super off peak window be 10-3pm in the winter. This aligns with both the costs experienced by SRP and with what other utilities, such as APS, are currently offering. This will reduce customer confusion, creates an evidence and cost based program, and does not unnecessarily penalize solar customers.
 
Fixed Fees
AriSEIA agrees with the other organizations that made comments on February 6th. Fixed fees should be as low as possible, as volumetric charges better align price signals with behaviors that improve efficiency. However, to the extent SRP has fixed fees, there should be parity between solar and non-solar residential customers. Solar customers should not be singled out for punitive and discriminatory fees.
 
Export Rate
SRP’s export rate is significantly below the other large utilities in Arizona. The valuation of the avoided cost is not correct. That methodology has not been highly scrutinized by the Arizona Corporation Commission or stakeholders because the Resource Comparison Proxy (RCP) framework has not yet rendered it necessary; however, SRP’s proposed export rate methodology in this case is inadequate. AriSEIA met with SRP extensively about our concerns with the value of solar study in 2024. The current cost allocation study does not correctly assign value to capacity costs and avoided transmission and distribution costs. We recommend that SRP adopt an export rate closer to that of Tucson Electric Power (TEP) to be evaluated on an annual basis and locked in for existing customers for a period of ten years, not one year. Even though SRP is three times larger than TEP, their current number of solar customers are comparable. Therefore, TEP is a reasonable starting place for an export rate that is fair to solar customers, but is closer to the current SRP proposal.
 
Additionally, any customers on a net metered rate should be allowed to stay on that rate until 2034 and not be inadvertently bumped in 2029, as is currently proposed.
  
If SRP provided more than two months to process this pricing proceeding, AriSEIA could provide a more detailed analysis and recommendation as to solar rate design. Organizations need time to hire an expert, have the expert review the workpapers, run their own analyses, and make a detailed recommendation. Therefore, we recommend the board set a vote on this pricing proceeding this summer, since the rate will not take effect until November of 2025, so that the best possible recommendations can be brought forward.
 
Commercial Rates
SRP seems to want to move to more plans with a storage component, but not in a way that will increase the adoption of storage. We recommend SRP adopt a pilot storage rate similar to the E-32L SP rate that APS adopted in 2024. APS developed that tariff in 2023 as a result of the prior rate case in a stakeholder process with AriSEIA. A copy of that tariff is included as Attachment A.
 
Recommendations
As such, AriSEIA recommends the Board offer amendments that accomplish the following:
 
1.      Move the final vote on the pricing proposal until summer of 2025, with new rates to still take effect in November of 2025;
2.      Open all four proposed rate plans to solar and non-solar customers;
3.      Default all new customers to E-28 with an opportunity to opt out;
4.      Have the super off peak time be 10-3pm in winter, instead of 8-3pm year round;
5.      Have the same on peak time of 4-7pm or 6-9pm on both E-28 and E-16 with the ability of the customer to choose which of those periods works better for their family;
6.      Move the export rate closer to that of TEP with a 10 year lock in, evaluated annually by SRP;
7.      Adopt a pilot commercial storage rate similar to APS’ E-32L SP;
8.      Grandfather all net metered customers on their current rate until 2034, if so desired by the customers; and
9.      Management should be directed to work with AriSEIA via a stakeholder process to develop a VPP program to be presented to the board by the end of the year.
 
Respectfully,
 /s/ Autumn T. Johnson
Executive Director
AriSEIA 
(520) 240-4757
[email protected]

[1] U.S. Department of Energy, Pathways to Commercial Liftoff: Virtual Power Plants, Sept. 2023, available here https://liftoff.energy.gov/wp-content/uploads/2023/10/LIFTOFF_DOE_VVP_10062023_v4.pdf. 

Same APS discrimination against solar customers 

Arizona Public Service likes to tout itself as somehow new and different. It is not the APS we remember involved in scandals at the Arizona Corporation Commission (ACC) or opposing renewable energy like with Proposition 127. They have new leadership and clean energy goals now. But if you are paying attention, APS consistently makes decisions that undermine renewable energy and hurt solar customers.

Last year, APS opposed the adoption of community solar in Arizona. Community solar is an option for customers that want rooftop solar, but cannot install rooftop solar either because they are renters, or live in multifamily housing, or have an older roof. It allows them to participate in the clean energy transition while also increasing a distribution grid resource and saving them money on their electric bills. The ACC ended up adopting a policy to kill any advancement of community solar in Arizona.

APS continues to ask for annual decreases in the export rate solar customers are paid for the extra solar power their rooftop panels produce and they sell back to the grid. APS buys it at a fraction of what it sells it to your neighbors for. APS has consistently fought against you having any options to sell that extra power elsewhere, including supporting HB2101 in 2022, which eliminated competition in the electric sector in Arizona.

APS simultaneously has advocated for increased fixed fees on solar customers. APS has nearly 200,000 customers with rooftop solar and it has advocated for all of them, every single one, to pay 15% more for the same power than their neighbors without rooftop solar. That new fee is the subject of ongoing litigation at the ACC and APS has most recently advocated for 74,000 of those customers to be completely excluded from the hearing entirely. These customers got solar years ago and are on rate plans called “Legacy Solar.” 

If APS is successful, not only will these customers be subject to APS’ discriminatory fees on solar, but they will be deprived of their due process rights, as well. APS has also argued (and won!) that the evidence used to substantiate this discriminatory fee on solar customers not be evaluated in the hearing. So, the evidence used to substantiate the fee is not part of the hearing in which the ACC decides if the fee is even legal.

Earlier this year, the ACC ordered APS to start a pilot program that aggregates the household batteries that customers pay for with their own money to offset energy APS needs when demand from customers is especially high. APS was ordered to undergo a stakeholder process and work collaboratively with the community to develop a fair program. Instead, APS has come up with a program that will almost certainly fail, because it inadequately pays for the resource it takes from customers. 

APS will continue to penalize solar customers unless the utility is held accountable. APS does not like solar customers because solar customers pay for their solar panels themselves. APS does not own them and does not earn a profit margin off of them. APS’ nearly 200,000 solar customers need to pay attention and need to tell the ACC that APS must stop its needless attacks on solar customers. 

Unfortunately, the ACC just sided with APS and determined that some solar customers may, indeed, be excluded from the rate case rehearing and that the underlying evidence APS provided to justify the discriminatory fees on solar customers will not be evaluated. This raises serious concerns about the validity of the rehearing. The public needs to reach out to the ACC in support of solar. You can file a comment with the ACC and be sure to reference Docket No. E-01345A-22-0144.
​
Autumn Johnson is executive director of the Arizona Solar Energy Industries Association.

Arizona Corporation Commission
1200 W. Washington Street
Phoenix, AZ 85007
 
RE: APS Virtual Power Plant (BYOD) Pilot Program, Docket No. E-01345A-22-0144
 
Chairman, Commissioners, and Staff,
 
Arizona Public Service (APS) is predicting unprecedented load growth over the next decade. To meet this rising need, the utility must aggressively add capacity which will put dramatic upward pressure on rates. One way to mitigate that upward rate pressure is to avoid direct utility investments where possible and to leverage customer owned assets to provide services that would otherwise require utility investment and risk ratepayer funds. To this end, the Commission ordered Arizona Public Service (APS) to implement the money-saving Bring Your Own Device (BYOD) program (also known as a virtual power plant (VPP)) which uses customer owned batteries to meet peak demand. The evidence in the rate case found that such a program could give APS access to batteries at a cost well below the cost of utility owned options.

AriSEIA/SEIA have raised several concerns about APS’s approach and its valuation methodology during the ongoing BYOD stakeholder process. APS has expressed consistent opposition to this program that could displace some utility investment opportunities from the start so it is unsurprising to AriSEIA/SEIA that APS’s methods and assumptions are designed to skew the outcome of this process in its favor. While we have some questions about the program implementation costs, the primary issue is with the value of avoided capacity and energy. The Company’s approach for valuing these categories does not reflect actual conditions on the ground and, as a result, produces avoided cost values that are substantially lower than justified.  Further, under the Company’s value, nearly all potential value from participating perfectly will be eaten up by the opportunity cost of forgoing peak time of use (TOU) reductions. Stated more plainly, APS’s proposal undervalues the important services BYOD can provide to such an extent that ratepayers will be unlikely to participate at all and would be better off simply reacting to the TOU rate. Rather than provide the appropriate price signal to customers to manage their battery for the broader good of the grid and all ratepayers, APS’s proposal will result in retrenchment to optimizing individual bill savings.

Capacity Value Issues

APS had indicated that it will use the Public Utility Regulatory Policies Act (PURPA) avoided capacity cost for the BYOD. Based on its Federal Energy Regulatory Commission (FERC) filing, this appears to be roughly $80/kW-year.  There are two key issues with using the PURPA avoided capacity value as a proxy for avoided capacity costs. 

First, the Company’s latest PURPA filing assumes that customer-sited microgrids are the capacity resource of choice. This is a non-conventional and inappropriate choice. APS was recently prevented by the Commission from pursuing additional customer-sited microgrid projects due to the impingement of its utility monopoly into a competitive market. This alone disqualifies this technology as the future capacity resource of choice, and any PURPA capacity costs based on this technology. Further, the Company has projected more than 4,000 MW of new capacity need over the following decade, and its integrated resource plan (IRP) shows that it will be procuring copious amounts of centralized generation and battery storage. Using a more conventional avoided resource such as a battery or gas combustion turbine (CT) or Company unit is more appropriate. AriSEIA/SEIA’s filing in this case used the annual revenue requirement of a utility-scale battery as a proxy, finding its avoided capacity value was north of $200/kW-year.

Second, PURPA is not driving investment in Arizona. The Company indicated that it has not signed any new PURPA contracts for years and the IRP filing does not rely on this financing mechanism for future procurements. Rather, it is procuring resources through competitive all-source contracts and through market-based purchases. Tying the value of this program to a moribund policy that is not producing new capacity is simply the wrong framework and should not be approved.

Energy Value Issues

The Company is using a simulated dispatch model to project avoided energy costs. This approach is necessarily tied to the input assumptions used and will necessarily not reflect actual real-world conditions, particularly during the scores of high-load/high-cost hours that the BYOD program will target. APS indicates that the average avoided energy cost is between $33/MWh and $52/MWh, a value that is simply inconsistent with historic market purchases during high-cost hours.

APS provided the quantity and price of its wholesale market purchases from 2018-2022 in the rate case.[1] An analysis of this data shows that the Company routinely paid in excess of $200/MWh for market purchases, with occasional purchases in excess of $1,000/MWh.  AriSEIA/SEIA’s analysis showed that the average weekday market purchase cost between 2019 and 2022 was over $100/MWh between 5 PM and 9 PM, the exact hours the BYOD program would target.[2] 

But if one looks at the actual highest-cost purchases, the avoided energy potential is much higher. AriSEIA/SEIA determined the 500 highest cost hourly purchases throughout the year and then analyzed the purchases that fell in the core summer months of June to September from 2018 through 2022.[3]  The results show that year after year, the avoided energy cost values during the highest cost hours are at times an order of magnitude larger than what APS proposes.

Even in 2019, which was an outlier in terms of the low quantity of high-cost market energy purchases, the average purchase during the high-cost hours was nearly $400/MWh. In 2021 and 2022 (and likely 2023), the price and quantity of high-cost purchases surged, with the average high-cost hour moving north of $800/MWh. 
Against this irrefutable historic purchase data, which has cost the Company’s customers tens of millions of dollars per year, the Company’s offer of as little as $33/MWh in avoided energy is simply unacceptable. AriSEIA instead recommends a minimum value of $500/MWh for avoided energy purchases for the BYOD program, a value which is roughly 1/3 of the highest cost purchase in recent years.

APS’s Proposal Is Eroded by TOU Opportunity Costs

By lowballing the avoided cost value on both the energy and capacity side, APS is setting the BYOD program to undercompensate customers for the real services they provide which will cause the program to fail. The residential value available to customers is only $40/kW-year based on the average reduction over the course of a program year.  The Company is authorized to call up to 60 events of up to 4 hours each between the hours of 4 PM and 10 PM.  Given that only half of these hours fall within the current peak TOU period (and fewer than half if events are called on weekends), customers participating in the BYOD event will have to consider the opportunity cost of peak TOU reductions. In other words, customers electing to participate in BYOD and give APS the ability to access the energy and capacity when they need it, may be inclined to simply participate in the TOU rate design thereby depriving APS and all its customers of the savings possible with BYOD.  

APS’s current peak and off-peak rates are roughly $0.34/kWh and $0.12/kWh, with a rate spread of $0.22/kWh.  Each kWh that a customer discharges their battery during an off-peak hour event call thus has an opportunity cost of $0.22. From this, it is possible to calculate the total opportunity cost that a BYOD customer faces by participating in the program.

In a best-case scenario, every event would be as short as possible (perhaps 2 hours) and fall during the peak TOU period.  In this case, discharges from the battery would not incur an opportunity cost and the customer could capture the full $40/kW-year benefit the Company proposes. In a worst-case scenario, every event would be 4 hours long and fall on weekends. This means that 100% of the event hours would incur the opportunity cost. A middle of the road scenario might assume event calls from 6 PM to 9 PM weekdays, with 2/3 of the hours occurring off-peak.
Suppose one analyzes an 11.5 kWh battery. The results of the three different scenarios are tabulated below. Even in the middle scenario, so much of the value of the program is eaten up by the opportunity cost that it is hardly worth the effort for a customer to sign up for the program. And in a worst-case scenario, it actually costs the BYOD customer money to participate in the program.

APS’s Stakeholder Process Violates Order No. 79293

Order 79293 (the “Rate Case Decision”) orders APS to “meet with AriSEIA/SEIA and any other interested parties to discuss collaboratively and attempt to reach agreement on the language of the BYOD Pilot POA.”[4] APS has held several stakeholder meetings in which it has told the stakeholders what it plans to do. AriSEIA requested an additional meeting to walk through the concerns identified above. APS sent out the proposed valuation that same afternoon. At the following stakeholder meeting, several stakeholders pointed out that the APS methodology was flawed and the valuation was too low and would make the program unsuccessful. APS requested stakeholders provide feedback in writing. Stakeholders asked for the Company’s workpapers. Stakeholders received two spreadsheets with two business days to review before the date in which APS asked for written feedback.

To date, it does not appear that APS plans to consider any stakeholder feedback in the plan of administration (POA) it intends to file within a month. APS is going through the motions of a stakeholder process, but there is nothing to indicate they intend to discuss collaboratively or attempt to reach agreement with stakeholders.

Respectfully,
 
Autumn T. Johnson
Executive Director
AriSEIA 
(520) 240-4757
[email protected]

[1] AriSEIA 4.03_ExcelAPS22RC03362_Hourly Market Purchases 2018-2022

[2] Lucas Direct at 59.

[3] This is twice as many as are allowed in the BYOD program, which authorizes 60 event days with events up to 4 hours.

[4] APS Rate Case Decision, Order No. 79293, 452:17-18, available here https://docket.images.azcc.gov/0000210704.pdf?i=1722230808744. 

FOR IMMEDIATE RELEASE
Contact:
Autumn Johnson
[email protected]
520-240-4757

Phoenix, AZ - Yesterday, the Arizona Corporation Commission (ACC) voted 4-1 to impose a new and discriminatory fee on rooftop solar customers in APS service territory. The new fee imposes a 15% greater increase on solar customers, over and above the rate increase that all customers will see starting on March 8th. The fee will show up on most customers' bills as a "grid access charge" and will be approximately $2-3 a month in addition the the rate increase everyone will get of approximately $10-12 a month, per APS. AriSEIA opposed the fee and offered an amendment to eliminate it from the rate case, which was not adopted. 

AriSEIA championed a Virtual Power Plant (VPP) program that was adopted 5-0 as a pilot program to commence next year. This program will save all ratepayers money, by allowing customers with batteries to opt in and share their battery capacity with APS when there is high demand on the grid, thereby limiting the need to build new, replacement resources.

The ACC also voted 5-0 to prohibit APS from competing with private industry in the microgrid space and voted 5-0 to correct on-peak hours for a commercial storage tariff called E-32 L SP, both upon AriSEIA's request. AriSEIA's request to stop disproportionately negative impacts from increased demand rates over energy rates on the E-32 M and E-32 L rate plans was not adopted.

"Yesterday was a challenging day for solar in Arizona. In a state with more than 300 days of sunshine, almost 400 solar companies that employ more than 8.250 people and contribute more than $1.5 billion to the state annually, we should be looking at ways to foster the sector, not penalize it. An unsubstantiated and discriminatory fee on solar customers is a step in the wrong direction," said Autumn Johnson, Executive Director of AriSEIA.

AriSEIA plans to file a Motion for Reconsideration on the solar charge and will engage with APS on the VPP program implementation.

AriSEIA is the state's solar, storage, and electrification trade association. It is the only trade association in the state that focuses on all scales of solar at every level of government, doing both regulatory and legislative work, and has boots on the ground.

While AriSEIA was successful in adding a Virtual Power Plant (VPP) pilot program in the course of the rate case, other aspects of the Recommended Opinion and Order (ROO) warrant changes. AriSEIA requested three changes. The most significant of which eliminates a brand new charge on solar customers that was not requested by APS or any other party in the case. You can read the comments at the link above. The vote is February 22nd.

Arizona Corporation Commission
1200 W. Washington Street
Phoenix, AZ 85007
 
Re: TEP Rate Case, Customer Storage Program Stakeholder Meeting, Docket No. E-01933A-22-0107
 
Chairman and Commissioners,
 
AriSEIA submits these comments in response to the compliance filing that TEP filed on December 7, 2023, in response to the stakeholder process they were ordered to commence regarding a Bring Your Own Device (BYOD) program (also known as Virtual Power Plant (VPP)) and revisions to the R-TECH and LGST-SP tariffs.[1] These stakeholder processes are the result of Order 79065.[2]
 
Because some of the utilities have recently been using their compliance filings as evidence in other proceedings and have also asserted that stakeholder silence is agreement, AriSEIA makes this filing to detail our numerous concerns about how TEP has so far engaged on BYOD, R-TECH, and LGST-SP. AriSEIA put forth a robust proposal to implement a BYOD program, as well as specific modifications to the R-TECH and LGST-SP in the course of the last rate case. Those proposals are the reason this stakeholder process was ordered. Further, TEP stated multiple times in the course of the last rate case proceeding that they had not had time to review the proposals. January will be one year since AriSEIA filed those proposals and TEP still seems unfamiliar with them.
 
BYOD is a win/win for AZ ratepayers and the utilities. AriSEIA’s BYOD proposal leverages private investment in distributed battery storage to provide much needed capacity to the grid at a price that is less than the cost of utility-owned, utility scale battery storage.[3] Further, any costs associated with the program are pay for performance only. There is no upfront payment, no subsidy, no cost shift.
 
At the stakeholder meeting held by TEP on November 17, 2023, TEP had no substantive content prepared, had no response to the AriSEIA proposals, had no proposals of its own, did not have the correct people at the meeting to discuss policy, nor did they articulate any plan for how to manage this process going forward. Further, despite the fact that the Order is clear as to what these stakeholder processes are meant to do, TEP was not clear in its direction to participants as to what we were even there to discuss. TEP permitted the meeting to devolve into a tangent conversation about wholly unrelated technologies or whether or not storage should even be considered, despite the fact that storage is the very reason the stakeholder process was ordered.
 
AriSEIA makes the following recommendations to the Commission and TEP:
 
1.      TEP should have the correct personnel at the stakeholder meetings to discuss policy and regulatory issues;
2.    The AriSEIA proposals on BYOD, R-TECH, and LGST-SP should be the basis on which the process unfolds. TEP should come to the meetings prepared to suggest components of these programs they can or cannot support;
3.     R-TECH and LGST-SP are separate issues and while they are to be discussed concurrently with BYOD, need not be discussed simultaneously;
4.     TEP needs to provide a capable facilitator of the meetings and process, either internal or external;
5.    If TEP wishes to host additional stakeholder meetings on unrelated topics or technologies, it can do so, but these processes should remain consistent with and adherent to the Order and the issues discussed in the last rate case; and
6.   TEP needs to articulate a process and timeline for this work. We suggest monthly meetings of one hour, which should be scheduled in advance with a stakeholder list, like TEP does for its other “collaborative” meetings.
 
AriSEIA’s proposal on all three matters can be found in Kevin Lucas’ direct testimony, filed on January 27, 2023, starting at page 314.[4] An excerpt of that testimony is attached herein.
 
/s/ Autumn T. Johnson
Executive Director
AriSEIA 
(520) 240-4757
[email protected]

[1] TEP, Notice of Filing-Tucson Electric Power Company’s Customer Storage Program Stakeholder Meeting Summary, Dec. 7, 2023, Docket. No. E-01933A-22-0107, available here https://docket.images.azcc.gov/E000032546.pdf.

[2] ACC, Opinion and Order No. 79065, Pg. 149, Lines 11-27, Aug. 25, 2023, Docket No. E-01933A-22-0107, available here https://docket.images.azcc.gov/0000209684.pdf?i=1701984045033.

[3] Kevin Lucas in APS rate case, hearing test., Sept. 1, 2023, Docket No. E-01345A-22-0144, 00:04:31 (this is also applicable in the TEP rate case).

[4] AriSEIA, Direct Testimony of Kevin Lucas, Jan. 27, 2023, Docket No. E-01933A-22-0107, available here https://docket.images.azcc.gov/E000023835.pdf?i=1701984045030. 

AriSEIA filed its final brief in the APS rate case today. The brief addresses false and misleading statements in APS' opening brief related to VPP, microgrids, community solar, E-32L SP, and its solar cost of service study. You can read the brief at the link above. A decision is expected in Q1.