Marine electrical power industry with renewable energy carriers. Part 1. Wind and wave turbines of offshore power plants

Abstract

The paper is devoted to offshore wind and wave power plants as an alternative to fossil hydrocarbon power engineering. It reports classifications and an analytical survey of the state-of-the-art of main types of offshore wind and wave turbines. The features of horizontal and vertical axes turbines constructions are described. Comparison of these two types of turbines has revealed the vertical axes design advantage since their height is two to three times less and its stability, accordingly, is higher. This allows expensive concrete tower constructions to be avoided and floating pontoons to be used, which is especially important for deep-water areas. The advantages of a two-contour wind turbine consisting of a fixed stator and a rotor directly connected with an electrical generator are highlighted. Due to the special “soaring in air” block construction of the turbine, the pressure on the seabed foundation is considerably reduced, allowing all the supporting structure for a floating pontoon to be replaced. The designs of wave turbines with direct and indirect operation are considered as well, the principles of harnessing marine wave energy are discussed and industrial prototypes of power plants of foreign firms are presented. With the help of analytical expressions, the evaluation of power performances is executed and a comparison of the power density criterion of wave energy with other kinds of renewable energy is indicated. It appears that the energy density of sea waves is an order greater of similar magnitude of wind and solar energy. On the basis of the idea of floating structures, the principles of designing hybrid and cluster offshore wind and wave power stations are suggested, where, with the help of power electronics and information technology, the electric energy of separate turbogenerators is integrated into a marine power pool system with HVDC underwater cable transmission to the consumers of a continental zone.