Residential solar+storage (my main focus in this post, rather than commercial or utility-scale versions) refers to a) an array of rooftop solar panels connected to b) some means of energy storage, usually a battery or batteries, controlled by c) smart software that enables the system to communicate with the grid.
Adding storage to solar radically expands its value — the whole is more than the sum of the parts. The ability to store energy gives the solar homeowner more control over her energy; she can shift her time of use, storing power when it’s cheap and selling it when it’s more expensive. And she can potentially participate in larger markets, as we’ll see later.
Keep reading at Vox.