Nowadays, ocean and other renewable energies have capability to produce clean and sustainable electric energy. Thus, various countries have developed renewable power plants for providing significant part of own required demands. Ocean currents have kinetic energy that can produce electric energy by rotating stream-kind turbines installed undersea. The velocity of ocean currents varies over time that makes produced power of ocean current converters varies, too. This variation affects various aspects of electric grids containing significant ocean current generators. The current paper considers both hazard of assembled elements of converter and change of its produced power to analyzes reliability of ocean current converters. To compute reliability indices of electric grid containing ocean current converters, both analytical and Monte Carlo methodologies are applied. In analytical methodology, a several-state reliability presentation is created for ocean current converter to compute reliability indices by total capacity-probability table. In Monte Carlo methodology, we produce random numbers for assembled elements of ocean current converters, and other traditional production plants to compute reliability indices of electric network. To analyze the suitability of suggested methodologies, simulation outcomes are discussed.