But the ramp-up is still underway, and it has been uneven across different battery chemistries. Most domestic plants produce older, nickel-based chemistries, said Laura LoSciuto, a manager in the RMI think tank’s carbon-free transportation team. The US has no domestic manufacturing capacity for lithium iron phosphate, or LFP, batteries — the preferred chemistry for grid-scale storage. A number of suppliers are “in various stages” of building LFP factories in the US, said Jeff Waters, CEO of Oregon-based energy storage company Powin. But those will take time to get off the ground.