Arizona Public Service (APS) has signed a 50 MW battery installation deal with First Solar, a solar power plant provider, in a deal that will provide ‘solar shifting’ capabilities for a new 65 MW solar farm in the state. Announced shortly after Arizona announced an 80% clean energy and 3 GW storage mandate, APS is hoping to get ahead of the curve – deploying what is currently scheduled as the largest battery in the US. APS, Arizona’s largest utility (with around 1.2m electricity customers), plans on using the 135 mWh battery to help store the electricity generated by the solar farm and deliver it when it is most needed. Broadly, the battery will store energy when customers are away from…