М.P. Rogankov, E.E. Мikushevitch, V.M. Mikushevitch, Ecopolis ltd, Мoscow, Russia

 In Russia all hydro power plants (HPPs) are referred to renewables, but small hydro and non-conventional are those with capacity less than 30 МWe. The word “non-conventional”, taken from the national standards GOST R 54100-2010, GOST R 51238-98, etc., is not absolutely correct for small HPPs; by the middle of XX century in the former USSR some 6600 small HPPs were in operation, later on almost all of them were dismantled. We can speak of the “second birth” of small hydro, which happened in the world and in our country during the last 20 years. Big hydro for a long time is a separate branch and in this article only small HPPs are considered.