We’ve already featured a couple of promising-looking energy storage companies getting close to commercialization (and claiming to offer safe, reliable, nontoxic grid storage at very competitive prices). And we’ve got a handful of other companies and technologies we plan to highlight in the coming weeks. But the announcement late yesterday from PG&E caught me by surprise.

It and the California Energy Commission just yesterday “unveiled an innovative battery energy storage system pilot project.” There are no details on the cost (just a note that $3.3 million came from the Energy Commission), but the press release does note that it is a “utility-scale sodium-sulfur battery energy storage project” and that it has a capacity of 4 megawatts, with the ability to store more than six hours of energy.