The exploration of ocean energy for electric power production offers a sustainable option to enhance the use of renewable energy. In this article, the reliability and cost analyses results of electricity collection systems proposed for a marine current farm are presented. A methodology based on the probability density function of site current speed is developed to determine the speed specifications of marine current turbine. Reliability analyses are conducted by taking electricity collection structure, equipment failure rate and probability distribution of turbine power output into account. Non-delivered energy cost in conjunction with the investment cost, power loss, operations and maintenance costs are included in the cost analyses. Ocean current speed data measured at the Taiwan coastline situated in the Kuroshio stream path are used to calculate the life-cycle costs of the studied energy collection systems. Simulation results show that marine turbine parameters can be effectively specified, and a sectionalized radial collection structure provides an efficient scheme for harnessing ocean energy.