Switch on more flow batteries! As part of the ongoing stimulus funding and the effort of the DOE to help bring large scale electricity storage to the market, SMUD has engaged to integrate a flow battery with grid operations in Rancho Cordova, CA. According to Sacramento Municipal (SMUD) the $7.3M project will incorporate 7 large scale batteries for load shifting, peak shaving, renewable energy integration and support for microgrid operations over a three year period.
In a post on a canadian website, the flow battery company has a system based on Zinc and salt water with claims of:
The battery has three times the energy density of lead-acid, is cheaper, and has an operating life of 30 years with virtually unlimited ability to cycle. “It’s cheaper than using pump storage,” Kennedy claims, emphasizing that this technology can affordably store renewable energy like wind and solar power today battery costs “less than” $200 per kilowatt-hour. That compares favorably to sodium-sulfur batteries from companies like Japan’s NGK, which cost about $250 per kilowatt-hour, and vanadium flow batteries from companies like Vancouver-based VRB Power, which cost about $400 per kilowatt-hour.
I point these out as further proof that “flow batteries” are a technology whose time has come. Why haven’t these large scale batteries become more important in the past? With inexpensive electricity generation based on coal and gas, there was little need or desire to integrate storage technologies that help stabilize or shift grid power. Now that renewables are increasing in Grid electricity supply, the momentary and time averaging benefits become of greater value. Clearly, as more utilities integrate renewables, there will be greater need and use of large storage systems.