Arizona’s state utility APS has been reprimanded by Democratic Commissioner Sandra Kennedy, who said that a fire in a battery storage installation run by Fluence, the AES-Siemens joint venture, highlights the “unacceptable risks” posed by lithium-ion batteries. This might just be bad PR, but if the complaint lights another fire under politicians, battery storage could take a real hammering in the US. Kennedy is not following the usual channels, publishing her comments in a letter independently of the other four members of the Arizona Corporation Commission (ACC) that has oversight here. Her letter is part of the ACC’s investigation into the fire at APS’ McMicken substation, which housed a 2 MW (2 MWh) battery provided by Fluence. The fire, which…