Arizona Public Service (APS) has installed two 2MW/2MWh lithium-ion battery systems from AES Energy Storage to test the technology’s performance in the desert temperatures of Phoenix.
The two battery systems have been put in two different locations along a feeder to a distribution grid as part of a solar program.
One battery has gone into the substation and the other sits in a walled enclosure halfway down the feeder, on open land adjacent to a housing development with a high proportion of rooftop solar.
APS aims to collect data on how each battery’s location affects its capabilities and to compare their performances to the traditional approach to voltage control.
Scott Bordenkircher, director of technology innovation and integration at APS, said: “No utility, to our knowledge, has ever done two identical batteries specifically sited in two different locations along a feeder.”
For correcting voltage, energy storage currently cost more by 40% to 60%, Bordenkircher said. But that’s only if you count that one application, and a storage unit can perform many functions.
“We’re not 100% sure on what the math is going to come out to be yet,” he said. But factoring in some peak-shaving, load-following for distributed solar, and the declining costs of battery cells, there’s reason to believe storage will be a clearer sell very soon.
“There’s no question that energy storage is definitely the next frontier; we’ve just got to get it right,” he said. “We’ve got to look at it from how do we do it efficiently and in an optimal fashion, rather than just throw a bunch of batteries everywhere and kind of cross your fingers.”
These installations mark a return to grid-scale energy storage for APS after a 1.5MW Electrovaya storage system in Flagstaff caught fire in 2012.
The new lithium-ion batteries come equipped with fire-suppression tanks and multiple layers of sensors to provide advance warning and response if anything starts operating erratically.