TY JOUR TI ANALYSIS OF THE COMPETITIVENESS INCREASE OF ENERGY-EFFICIENT DESIGNS OF WIND TURBINES OF VARIOUS TYPES KW horizontal axis wind turbines KW vertical axis wind turbines KW Darrieus rotors KW Savonius rotors KW combined wind turbines KW autonomous power supply JO Vestnik of Astrakhan State Technical University AU Ilyin, R.. AU Shishkin, N.. PY 2017 IS 2017 PB Astrakhan State Technical University