An on-site or embedded power storage unit regularly hold vital equipment working during short energy outages. This buffer against losing power prevents inconvenient or dangerous stoppage of crucial procedures. When the cycle is completed, the equipment may be safely operated straight down with just minimal risk or damage. Back-up devices are generally used for personal computers, but production equipment can also be safeguarded with an urgent situation energy supply. In some cases, the back-up electric battery only provides enough power to help keep methods running until back-up generators can be brought online.