Subject Matter of Contract of Services for Maintaining Reserve Heat Capacity

In the paper, author analyzes subject matter of contract for provision services to maintain reserve heat capacity. The notes that capacity is almost only in field supply, definition which not legislation. At same time, this problem covered legal literature. To disclose under study, refers such categories as «power», «heat capacity», «reservation (booking)", «reserve capacity». paper presents provisions doctrine and judicial practice on nature power energy sector, offers author’s own point view essence reservation (reservation) a category. On basis formulates question, absent legislation, determines its place system civil law contracts non-defined contract.