Editorial authored by Joseph Gardner, Power System Program Manager, SRP
When people ask me what pumped storage is, I like to keep it simple: think of it as a battery—but instead of lithium or chemicals like those that are used in our phones or our cars, it uses water. It’s one of the oldest and most reliable forms of energy storage in the world, and it’s about to play a major role in Arizona’s energy future.
How pumped storage works
At its core, pumped storage is a straightforward concept. We move water between two reservoirs — one higher in elevation, one lower — using electricity to pump the water to the higher reservoir when demand is low or when we have excess solar or wind energy. Then, when demand spikes, we release that water back downhill to the lower reservoir through turbines, generating electricity and putting it back on the grid. It’s clean, efficient and incredibly effective.
As a Program Manager at SRP, I help oversee the outreach and regulatory aspects of our pumped storage project. Beyond the technicalities, I’m passionate about what this project means for our customers and our communities. This isn’t just about meeting today’s energy needs — it’s about building a resilient, sustainable system for generations to come.
This project has the potential to store and generate up to 2,000 megawatts of electricity. To put that in perspective, that’s enough to power between 225,000 and 450,000 homes for 10 hours. And unlike many energy technologies that need to be replaced every few decades, this facility is designed to last for over 100 years. It’s a multigenerational investment in Arizona’s future.
One of the most exciting aspects of pumped storage is how it complements renewable energy. Solar power is abundant in Arizona, but it doesn’t always align with when we need electricity the most. Pumped storage uses that midday excess solar energy to pump water uphill. When energy demand peaks in the evening, the water is released downhill to generate pumped storage hydropower. It’s a perfect match.
Putting safety first
I know that some customers have asked about the new upper reservoir and why it won’t be open for recreation. The answer comes down to safety and operations. The water levels in that reservoir will fluctuate dramatically — sometimes over 100 feet — as we move water between the two reservoirs. That kind of variability makes it unsafe for boating or swimming. With that being said, we are exploring ways to make the area around the reservoir accessible for hiking and other low-impact recreational activities.
Why use water for energy storage
Being that we’re in a drought, many ask why we would use water for energy storage. It’s a fair question. SRP has water stewardship in our roots, managing the Salt and Verde rivers for over 100 years. Both watersheds are largely fed by winter rains and snowmelt and stored across millions of acres of forest. These systems are in relative balance, meaning we’re generally receiving as much or more water than we’re delivering. Even in times of severe drought, this project wouldn’t disrupt how we store and deliver water. We are always working to ensure our local watersheds are sustainable, and we’re committed to managing them responsibly.
At the end of the day, this project is about more than just megawatts. It’s about affordable, reliable and sustainable power and water. It’s about making sure that when you flip the switch — today, tomorrow or 50 years from now — the power is there. And it’s about doing that in a way that respects our environment, our communities and our future.
That’s why I believe in pumped storage and that’s why I’m proud to be part of this project.