Fees being charged to interconnect residential storage systems to the grid in California are “arbitrary” and “punitive”, while some may even be illegal, according to US installer SolarCity.

Over two-thirds of German PV installers are now offering their customers energy storage options, while their British and Italian counterparts are beginning to follow suit, according to a new report from EuPD Research.

Neither commercial-scale nor energy storage have yet take off in the US. But as Felicity Carus reports, this could be about change as companies eye opportunities in both segments.