First developed by NASA, flow batteries are a potential answer to storing solar – and wind – for eight to 10 hours, far beyond what is commonly achieved today with lithium-ion. In the second of a two-part special report, Andy Colthorpe dives deeper into questions of bankability, market segmentation and manufacturing strategies with four very different providers of flow energy storage technology.

The opening address and a handful of sessions took place on Monday for SPI/ESI at Anaheim Convention Center, California. While the two shows are national and international, it is expected there will be a great deal of attention paid to the state’s SB100 bill.