There are a few ways to store solar. The most common is in a battery so the power can be used at a later time in the day or at night or saved for an outage. With a battery the home or business uses the solar direct from the panels and if there is any excess this is stored to be used at a time when you need it. The other concept is virtual storage or feed in. This is where in a cost sense you sell power to the grid at a certain rate and then you buy it back at a later time if needed. The virtual storage/ feed in depends on the agreement but generally you will only get about ⅓ to ½ on the feed in vs what they would charge back. This is however a good way to make use of excess solar that you would otherwise not use.