The installation potentially represents a groundbreaking step for the PV industry, as it looks to become a mainstream supplier of clean, reliable electricity around the world.

The €5.5m ($7.1m) ILIS project, as it is known, was initiated by Acciona and French battery-maker Saft in 2010, and has been integrated into an existing PV array built a decade ago by Acciona in Navarre, Spain.

The