Solarisation of the existing small and medium-capacity hydroelectric power plants includes their equipping with more powerful PV pumps that would make river flow back to accumulation during sunny periods. In this way, without reduction of consumption of all the more precious (and expensive) mountain water larger quantities of electric power would be produced.

According to Todorovic Z., combined hydro-electric power plant of 50 MW and solar power plant of 1 MW, operate at peak rating 3 hours a day, providing conditions for an average daily production of 4,060 kWh (1,000 kWh more than if only hydro-electric power plant would operate). [10]

There are about 50 small hydroelectric power plants in operation in Serbia and Montenegro (Srbija i Crna Gora — SCG) today, producing about 250 GWh a year, which is only 11% of technically usable hydro potential of small hydroelectric power plants. According to domestic estimates, on small mountain water currents, new small-capacity hydroelectric power plants of a few kW to 10 MW, would be built that would produce more than 2,000 GWh per year.

Their selective equipping with solar pumps, production of electric power in summer period may be increased by almost one quarter. Estimate of dynamics of solarisation of small hydroelectric power plants in SCG for the observed period is given in Table 7.

After positive experiences with experimental plant with of 40 kW solar pumps in 2006, it is assumed that power rating in 2007, will be for times higher and later on increased on selected, already existing small hydro-electric power plants.

With announced privatization of SCG energetic sector, conditions will be created for installation of new reversible solar mini hydroelectric power plants that would actually be able to engage another 380 and 400 kW of solar cells in 2009, and 2010, respectively.