FIELD: power engineering. SUBSTANCE: device is connected to many users 11, 12 at least some of them (11) being equipped with emergency power supply incorporating storage batteries 13 and rectifiers 15 supplied with power from mains 14. In case of short-time peak load in mains 14 part of energy supplied from storage batteries 13 of individual emergency-power lines 23 convey power to mains 14 as long as peak demand exists and storage batteries 13 are capable of supplying emergency power. EFFECT: reduced cost of power supplied during peak demand intervals. 27 cl, 2 dwg
