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Rate Case 2025: Update
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In June 2025, APS filed a request with the Arizona Corporation Commission (ACC) to update rates to support investments we’re making that provide customers with reliable, resilient power at the lowest cost possible.
Key points of this rate request
We’re investing in reliability & resilience
Customer rates support investments that enhance reliability under increasingly demanding conditions, including wildfire risk, extreme weather conditions and cyber and physical security threats, strengthening the energy grid that we all depend on.
We’re making sure data centers pay what it costs to serve them
We've proposed over a 45% rate increase for extra-large energy users like data centers to help ensure that they continue to pay for their costs of service. Our formula rate request would provide an annual process to ensure that other customers are not receiving cost increases associated with data center growth.
We’re updating rates to match what it costs to provide reliable service to our customers
Today’s rates were set based on costs incurred in 2021 and 2022, and costs have risen sharply since then. This proposal brings rates closer to current costs of service and supports ongoing investments made to meet demand and improve reliability.
Related News and Information
Data Centers: How We’re Protecting Customers While Planning for Big Energy Needs
Here's what APS is doing to protect reliability and affordability for residential and small business customers while working to meet the needs of this unique business sector.
How Customers and Arizona Communities Benefit from APS Earnings
You may hear about APS profits and wonder how that fits with a rate case request. Here are the facts.
Escalating costs impact common grid materials
Over the past five years, the prices of power poles, transformers and overhead wires, and other materials have risen sharply, in some cases doubling in cost.
Click to enlargeThe rate case is a public, collaborative process that typically lasts more than a year. New rates are not expected to go into effect until much later this year.
We understand rising costs are impacting so many aspects of customers’ lives today and that it’s never easy to hear bills could increase. That’s why we’re focused on doing our part to keep our costs down as much as we can, while giving customers tools, programs and choices to help them manage their bills. Reliability is critical in Arizona, and we work hard to ensure the power is there when our customers need it most. Thank you for trusting us with your energy needs.
Related materials
The application for new rates supports:
Investing in reliable and resilient energy
This case supports investments in our energy infrastructure to provide you with the energy you need, when you need it. Despite extreme temperatures in Arizona, our customers experienced less than one power outage and faced fewer minutes of interrupted service last year than the nationwide industry average. We’re looking ahead to keep your energy reliable in the future, too — continuing to make upgrades to our energy infrastructure that protect against severe storms, prolonged periods of extreme heat, and risks from physical and cyber attacks.
- Addressing rising expenses: We’re committed to balancing the need for low-cost power with the critical importance of investing in the reliability and resilience customers expect. Base rates were last updated in 2024, to reflect costs from 2021 and 2022. Since then, APS has experienced rapidly rising costs in operations and equipment needed to deliver energy to customers.
- System upgrades: This includes pole repair and replacement, substation and grid technology improvements.
- Wildfire mitigation: We’re upgrading the electrical system with fire resistant equipment and installing technology that provides early warnings if a fire does start. Learn more.
- Reliability investments in action: We’re investing in innovative technology for quicker power restoration times like Fault Location, Isolation and Service Restoration (FLISR) to help us detect and automatically respond to outages, in real time. Learn more.
- Optimizing a balanced mix of energy sources: Improvements at sites like Palo Verde Generating Station and Redhawk power plant increase efficiency during the hottest months. We’ve brought on new generation at the Sundance Power Plant and Ironwood Solar Plant and added energy storage at the Agave Solar Plant to capture renewable energy for use when customer energy demand is highest.
- Safe and secure: Increased protection against physical and cybersecurity threats.
Keeping costs as low as possible
We know costs are rising everywhere so we’re doing what we can to keep our own costs down. We’re also working to ensure high demand business customers, such as data centers, pay what it costs to serve their high electricity needs without placing the burden on residential and small business customers. It also means bringing gradualism in pricing through new tools such as formula-based rates.
- Find cost savings: Our employees are trained to find efficiencies and save money, passing on those benefits to customers. Read about how engineers at a power plant found a way to save millions of dollars.
- Adjusting rate design: Large business customers, such as data centers, will pay what it costs to serve their high electricity needs without placing a cost burden on other customers. Learn more.
- Updating Grid Access Charge: To better align rates with the cost of service, customers with rooftop solar will see an additional increase. This is a step towards reducing shifting those costs to customers without rooftop solar.
- Gradual, annual rate adjustments: We’re proposing to use formula rates in the future, to make rate adjustments, either up or down, based on the previous year’s expenses and investments. Watch this video to learn more.
- Participating in Western energy market: APS focuses on meeting customer needs on the hottest days. On less extreme days when we have more energy than our customers need, we sell it on the market, with those sales lowering overall customer costs. Over the past five years, this has provided a $450 million benefit to customers.
Continuously improving our support for customers
We are committed to delivering excellent service that meets your expectations, while adding value at every touch point.
- Support for limited income customers: APS is committed to assisting limited-income customers through the state’s most generous low-income Energy Support discount program, as well as various bill assistance programs including Crisis Bill. If you’re experiencing difficulty paying your energy bill, we highly encourage you to contact us. We work closely with customers to find financial assistance that will help them. More information is available at aps.com/assistance or by calling (602) 371-7171.
- Adding technology: We’re investing in technology to quickly notify customers with important information about outages, account status, and emergencies. Sign up for alerts.
- 24/7 customer service: Customers can get the support they need through our top rated Arizona-based live agents every day of the year, 24 hours a day, or through one of our digital platforms.
APS is here to support customers. If you need help with your bill, visit aps.com/assistance or call our Customer Care Center at (602) 371-7171 or (800) 253-9405. Advisors are available in English and Spanish.
Frequently Asked Questions
Unlike most companies who can independently set their own prices for the goods and services they provide, APS is a regulated utility that must file a request with the Arizona Corporation Commission (ACC) to open a public process called a rate case. Every few years, we file these requests asking the ACC to review the cost of delivering power to determine the appropriate amount APS can charge customers.
APS last filed a rate case in 2022, which resulted in the ACC approving new rates in 2024 based on costs from 2021-2022. If the current request is approved as proposed, the monthly bill impact to a typical residential customer using 1,000 kilowatt-hours would be around $20. Many factors affect a customer’s bill amount, including how much energy was used, weather, their rate plan and the number of days in a billing period. Rate changes would not take effect until much later this year.
APS last filed a rate case in 2022, which resulted in the ACC approving new rates in 2024 based on costs from 2021-2022. If the current request is approved as proposed, the monthly bill impact to a general service customer would be between 6.5 - 30%, depending on the customer class. Many factors affect a customer’s bill amount, including how much energy was used, demand, weather, their rate plan and the number of days in a billing period. Rate changes would not take effect until much later this year.
The rate case process generally takes about a year, depending upon the complexity of the issues and number of participants.
- APS files a notice of intent (NOI) to file a rate case. Completed: May 2025
- APS files its rate case, which includes details of its request. Completed: June 2025
- Participants and ACC staff have an opportunity to provide testimony.
- Public is invited to provide comment on the proceeding. January - May 2026
- ACC administrative law judge (ALJ) hears the case. May 2026
- ALJ issues a recommended opinion and order (ROO).
- Commissioners hold an open meeting to discuss and vote on the ROO.
Current rates are based on expenses from 2021-2022 and do not reflect today’s cost to serve customers. Since then, we have invested more than $2 billion every year maintaining and improving our infrastructure to reliably serve our customers. Higher interest rates and inflation also are driving the need to update to our rates. For example, the cost of transformers, a critical component of providing energy to homes and businesses, is 64% higher now than when our current rates were set. The case we are filing this year seeks to recover investments made, based on 2024-2025, to determine the appropriate amount APS can charge customers going forward.
Our focus is to strengthen the reliability of Arizona’s electricity infrastructure, provide power to new customers while protecting existing customers from bearing those expenses, support continuous improvements in meeting the needs of our customers, and keeping costs as low as possible. A key element of our request is a new tool which allows for smaller, annual price changes – that can be reductions or increases – based on the previous year’s expenses and investments. With these formula rates, APS would report each year how much it costs to serve customers, and make adjustments if necessary. If extra-large customers (like data centers) cause costs to rise, those costs will be assigned specifically to them.
We’re continually investing in a balanced mix of energy resources and infrastructure to deliver reliable power while keeping your bills as low as possible, including:
- Investing in the operation and upkeep of Palo Verde Generating Station preserves the life and safe operations of one of the country’s largest energy producers, and the benefits of its 100% carbon-free energy around the clock. More than $44 million in plant improvements and system replacements at Palo Verde are included in this rate request.
- Addition of the Agave Battery Energy Storage System, Ironwood Solar Energy Plant and of two natural gas units at the Sundance Power Plant – are recent investments included in this rate request.
- Maintaining our existing, flexible natural gas power plants which strengthens our ability to deliver reliable energy to customers on hot summer evenings when the sun is setting, and demand is high.
Additionally, we’re making the grid more resilient during extreme weather with our fire mitigation efforts such as pole replacement, vegetation management and smoke detection cameras, and installing smart grid technology that allows our crew to isolate and reroute power for quicker restoration times. These are just a few of the many improvements that help provide customers with reliable power.
APS offers the highest discount and funding for limited-income utility customers in Arizona. In 2025, more than 85,000 limited-income customers received a 25%, 35% or up to 60% discount on their bill for approximately $56 million in savings. In addition, nearly 21,000 customers received more than $12.7 million in assistance from state, federal, APS shareholders and other sources. We highly encourage and work closely with customers to find the financial assistance that will help them with their energy bills. Learn more.
We also offer resources to help customers learn more about ways they can conserve energy, find their Most Economical Plan, and tips to save on their bills all year long. Budget Billing is also available for customers to levelize monthly bills and reduce the seasonal swings Arizona weather can cause to bills. Learn more.
You are invited to participate in public comment sessions on this rate case organized by the Arizona Corporation Commission (ACC) at 1200 West Washington Street, Phoenix, Arizona 85007 or by calling 1-877-309-3457 and using passcode 801972877##:
- January 20, 2026 (Telephonic and in-Person) 1:00 p.m. to 4:00 p.m., or until the last caller is finished speaking, whichever comes first.
- January 26, 2026 (Telephonic Only) 6:00 p.m. to 8:30 p.m., or until the last caller is finished speaking, whichever comes first.
- February 18, 2026 (Telephonic and in-Person) 10:00 a.m. to 1:00 p.m., or until the last caller is finished speaking, whichever comes first.
- February 18, 2026 (Telephonic Only) 6:00 p.m. to 8:30 p.m., or until the last caller is finished speaking, whichever comes first.
- May 18, 2026 (Telephonic and in-Person) 10:00 a.m. to 1:00 p.m., or until the last caller is finished speaking, whichever comes first.
You can find additional documents related to this rate case on the ACC’s website (docket #E-01345A-25-0105).
If you have any questions concerning our filing and application, you may contact APS at: 400 N. 5th St, M.S. 9708, Phoenix, AZ, 85004, Attn: Rate Case Manager; by calling 602-250-2767; or emailing ratecase@aps.com.
