COMPLEX ASSESSMENT OF EFFICIENCY OF POWER UNITS USING THE RENEWABLE POWER SOURCES
A comprehensive assessment of the efficiency of power plants using renewable energy sources (RES) is performed. Under the existing tariff for heat energy, the minimum allowable cost of solar collectors of solar heating units (SHU) at a payback period of 7.0 years should not exceed 2 300 rub/m <sup>2</sup>. The capital expenditures on the proposed SHU of gravitational type are 1.4-1.6 times lower than those on the traditional SHU of the circulation type, while the payback period does not exceed 5.0-5.7 years. When the electricity tariff in the Astrakhan region is 3.76 rub/(kW∙h), the minimum allowable specific capital investments in wind turbines with a payback period of 7.0 years should not exceed 46 000 rub/kW. The wind turbines produced by LLC "GRC-Vertical", American company "Falcon Euro" and the original proposed combinations of wind turbines have good technical and economical parameters. The calculations show that the cost of biogas produced at biogas installations (BI) with an average and high power is lower than the price of natural gas at domestic market reaching now 120 $/thousand m <sup>3</sup>. The cost price of the biogas produced by the BI of low power is 80-270 $/thousand m <sup>3</sup>, when used for heating the biomass of renewable energy sources it decreases up to 30-100 $/thousand m <sup>3</sup>. Taking into account the significant capital expenditures on construction and exploitation of gas networks in far rural areas in many regions in Russia, the use of the biogas installations of not only high and average power but also of low power can be economically profitable even now for heat and gas supply for many consumers. Key words: solar water heaters, windmill, biogas installations, thermal energy, electrical energy, cost of installations.