PHOENIX (AP) - Arizona's largest electric company installed massive batteries near neighborhoods with a large number of solar panels, hoping to capture some of the energy from the afternoon sun to use after dark.
Arizona Public Service has been an early adopter of battery storage technology seen as critical to the wider deployment of renewable energy and for a more resilient power grid.
But a fire and explosion at a massive battery west of Phoenix that injured eight firefighters and a police officer in April highlighted the challenges and risks that can arise as utilities prepare for the exponential growth of the technology.
The incident is being closely watched by energy storage researchers and advocates. APS has assembled a team of engineers, safety experts, first responders and others to investigate.