It’s likely a strong indication of the way the world is adopting renewable energy rapidly that just under a month ago, one of the best-established trade shows for solar in the US featured what seemed like almost as much space dedicated to national and international energy storage companies and technologies, as it did for solar.

Lithium-ion battery-based energy storage for commercial and industrial customers in the US lies on the cusp of becoming “viable” over the next three to five years, according to international credit rating agency Moody’s.