Uninterruptible Power Supply (UPS)
An Uninterruptible Power Supply is an option available for any solar energy system. This will provide you with continuous energy service during blackouts. The uninterruptible power supply will usually contain batteries or be used in conjunction with batteries.
An Uninterruptible Power Supply (UPS) is ideal for "mission critical" equipment, especially for construction or mobile camps, for example. A UPS does require equipment to be in close proximity (close enough to be connected with a limited length of wiring, that is). A UPS also comes in various sizes, depending on what you need to power.
Double conversion systems offer the very highest protection for your system.
Uninterruptible power supply is also used in personal computers for the same purpose - a battery takes over the power supply when other sources (i.e. the regular power grid) have failed.