New Salt River Project reservoir

New legislation will allow Salt River Project (SRP) to build a new reservoir near Apache Lake to be used for the sole purpose of power generation. SRP has been comparing two sites in canyons high above Apache Lake.

Ron Klawitter, SRP’s Manager of Water System Projects Group discussed plans for the new reservoir.

“This project is looking at how we can better use renewable energy and keep the lights and air conditioners running during the day and into the evening hours when it’s still hot like we’re seeing at this time of the year,” Klawitter said.

The new reservoir would function like an electric battery, releasing water through a hydropower dam and into Apache Lake when electricity is needed for SRP customers in the Phoenix area. SRP would use surplus power on the grid, likely from solar plants, to pump water from Apache Lake about 1,000 feet back up the mountains to refill the 100-200 acre reservoir.

“Absolutely, pump storage is sort of the world’s oldest battery; it’s very simple. It pumps water uphill when we have excess energy, we want to store, and it runs water downhill through turbines when we want to put it back on the grid,” Klawitter said.

Klawitter said they are in the early stages of planning the new reservoir while having as little impact on the lakes and the environment as possible.

“What we call that is round trip efficiency, how energy you put in to get the same amount out. Pump storage facilities are about an 80% efficiency factor; other energy storage like batteries are on the order of 80 to 85%, so pretty similar efficiency factor compared to other energy efficiency storages,” Klawitter said.

One of the reasons the specific sites were chosen was because there is more than 1,000 feet of elevation between both sites. Klawitter said 2023 was one of the biggest snowpack years since the 1970s, and the season ended with the reservoir 100% full.

“We are looking at different options. We are planning out 10, 15, 20 years for what the future of energy systems looks like, customer demands looks like,” Klawitter said.