Although ocean currents are more stable than wind, the present cost of energy produced by ocean current turbine is considered to be higher than that of offshore wind turbines. It is caused by the expensive cost of submerged devices and difficulties of their maintenance. To solve the problem, the authors are developing a new concept of a cross flow turbine for high economic performance. The turbine axis of the concept is not fixed in the upright position for the reduction of supporting structures and device cost.
Since a firm foundation is not available in ocean environment, discarding the idea of fixed turbine axis position is a very natural approach in ocean engineering. The economic performance of the proposed turbine is estimated based on the existing cost analysis of floating wind turbines and ocean plants. Although there are remaining problems of high mooring tension, possible changes of ocean current path and survivability in rough sea conditions, the result shows favorable economic performance of the concept.