This paper is devoted to consider a use of hydropower of small rivers; the feed-in tariff system for small-scale hydro power plants (SHPP), its disadvantages and opportunities to remove them. Cooperative game theory approach is used for evaluation of possibilities to gain additional income and analysis of regime management of the small-scale hydro power plant. Technical and economical aspects of the issue are observed in the paper. Offered approach is demonstrated on an example with 10 players (9 SHPPs and a public trader). The obtained results demonstrate the validity of the cooperation for obtaining additional income.