Achieving our Clean Energy Commitment will include various methods such as relying on Palo Verde; increasing clean energy resources, including renewables; promoting energy efficiency; and optimizing regional resources.
Nuclear. Palo Verde Generating Station has been the nation’s largest power producer of any kind for 30 years – all of it clean and carbon-free. As the heart of the APS generation fleet, it provides the foundation for the reliable service our customers count on.
The plant is a critical asset to the Southwest, generating more than 32 million megawatt-hours annually – enough power for roughly 3.4 million households or 8.5 million people. In addition, Palo Verde provided much needed support during the recent Texas power crisis by delaying the start of equipment reliability repairs enabling full-power output when it was most needed.
Nuclear energy works with renewable generation to create a more reliable, diverse clean-energy portfolio. Palo Verde produces clean energy at all hours supporting the basic electrical needs of our customers when solar and wind are not available. Without nuclear energy, carbon emissions would increase due to a greater reliance on carbon-emitting fossil fuels to fill the inevitable energy void during periods of low renewable generations, such as after sunset. Nuclear energy can facilitate increased adoption of EVs and improve the environment by supplying zero-emission energy to charge EVs and large-scale batteries.
While Palo Verde has seven owners in four states, nearly half of its output is dedicated to serving Arizona consumers. Electricity generated by the plant annually displaces more than 13.2 million metric tons of greenhouse gas (GHG) emissions that otherwise would have been produced. It is estimated that Arizona’s energy-related emissions would be about 14% higher without the displaced carbon emissions from Palo Verde.
Additionally, as the nation’s only nuclear plant not located on a body of water, Palo Verde recycles more than 20 billion gallons of wastewater annually from surrounding municipalities to cool the plant. This represents more than 20% of all effluent used in Arizona.
Learn more about Palo Verde Generating Station .
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Renewables. With nearly 300 sunny days each year in Arizona, APS and its customers are transforming sunshine into a renewable energy source that powers an increasing number of homes and businesses across the state. APS supports customers interested in protecting the environment and reducing their energy bills by installing renewable energy technologies like rooftop solar systems at their homes, schools and businesses. Nearly 141,000 solar systems on customer rooftops and parking structures are already connected to the APS smart grid, providing almost 1,300 megawatts of robust solar capacity. In 2021 the amount of residential solar generating capacity installed in APS service territory was 20% higher than 2020. Nationally, only Hawaii and California have more residential solar capacity per capita than Arizona. As the largest electricity provider in the state, APS and its customers have been a big part of that achievement:
- APS ranks fourth nationally for the percentage of residential customers with rooftop solar systems
- APS customers installed a record amount of residential solar capacity in 2021
- 15% of all single-family homes in APS territory have a solar system, and that number continues to grow
Learn more about our solar path for a cleaner, greener Arizona.
Renewable Energy Portfolio. In 2006, the Arizona Corporate Commission (ACC) adopted the Renewable Energy Standard (RES). Under the RES, electric utilities that are regulated by the ACC must supply an increasing percentage of their retail electric energy sales from eligible renewable resources, including solar, wind, biomass, biogas and geothermal technologies. The renewable energy requirement is 12% of retail electric sales in 2022 and increases annually until it reaches 15% in 2025.
At the end of 2021, APS had a diverse portfolio of existing and planned renewable resources totaling 2,758 megawatts, including solar, wind, geothermal, biomass and biogas. Of this portfolio, 2,218 megawatts are currently in operation and 540 megawatts are under contract for development or are under construction. Renewable resources in operation include 247 megawatts of facilities owned by APS, 736 megawatts of long-term purchased power agreements, and an estimated 1,235 megawatts of customer-sited, third-party owned distributed energy resources.

Learn more about our Renewable Portfolio.
APS’s strategy to achieve its RES requirements includes executing purchased power contracts for new facilities, ongoing development of distributed energy resources and procurement of new facilities to be owned by APS. In December 2020, APS issued two Request for Proposals (RFP): a battery storage RFP for projects to be located at two AZ Sun sites; and an all-source RFP that solicited resources to meet our clean energy needs and capacity to maintain system reliability and was later amended to include a request for 150 megawatts of solar resources to be developed on APS property and owned by APS (collectively, the “December 2020 RFPs”). As a result of the all-source RFP, APS executed a PPA in October of 2021 for a 238 megawatt wind resource to be in service by June 2023, and also executed an engineering, procurement and construction contract in November of 2021 for a 150- megawatt solar resource to be owned by APS and in service in early 2023. APS continues to negotiate contracts for additional resources to be in service in 2024 in connection with the all-source RFP. Once it secures those important resources and closes out the December 2020 RFPs, APS intends to issue its next all- source RFP to address resource needs for 2025 and beyond.
Learn more about our Integrated Resource Plan and RFP expansion for APS- owned solar.
Demand Side Management. Technologies such as rooftop solar, LED lighting and smart thermostats have given customers more power to control their energy usage and potentially reduce their costs. As more emerging technologies such as energy storage devices become commercially viable, they will continue to change how customers interact with us. By being proactive and working with our customers to identify and respond to their changing needs, we remain well positioned to deliver value. And by providing customers the opportunity to manage their energy and peak demand, we can expand the use and understanding of load-management technologies, encourage customers to reduce CO2 emissions, use energy during off-peak hours and better align with solar production and system peak conditions. Taking these innovations to scale will help us achieve our bold clean energy commitment.
Learn more about our evolving residential energy management to be a clean peak resource.
APS’s demand-response programs use a virtual network of smart home products, like thermostats, water heaters and pool pumps, to reduce energy use on Arizona’s hottest summer days and shift energy demand to when more solar power is available. Chief among the programs connected to the APS virtual power plant is the company’s signature residential thermostat program, APS Cool Rewards. With more than 57,000 residential smart thermostats enrolled, customers benefit from incentives, discounts and energy-savings options for voluntarily conserving energy. APS Cool Rewards boasts a capability of shedding more than 80MW of energy from APS’s smart grid. This energy avoidance saves customers money, helps the environment and builds a more robust electrical grid. APS Cool Rewards is recognized as one of the five largest Bring Your Own Thermostat (BYOT) programs in the country and one of the largest utility-managed thermostat virtual power plants. APS has a 2022 goal of reaching 110,000 thermostats to provide over 130 megawatts of summer capacity.
Learn more about the role of our customers, virtual power plant and customer programs.
