Tidewheel

Tidewheel is a proposed tidal energy technology that seeks to convert the kinetic energy of moving tidal water into electricity through a large rotating wheel. In typical designs, a submerged wheel is mounted on a central axle and fitted with blades or vanes around its circumference. As tidal currents push on the blades, the wheel turns, and the rotation is transmitted to a generator either directly via a drive shaft or through a low-speed gearbox, with the electrical output conveyed to shore by subsea cable.

Design variants vary in placement and drive method. Some concepts place the wheel across a tidal channel to capture both flood and ebb currents, while others use a drift-free, single-direction rotor coupled to a yawing system. A few proposals aim for a direct-drive, gearless configuration to reduce mechanical losses.

Development history is limited to theoretical studies and small-scale lab experiments, with only a handful of field demonstrations reported in niche marine energy programs. Reported advantages include a relatively simple, robust rotating element and potentially lower nacelle mass compared with conventional tidal turbines. Challenges focus on maintaining efficiency across a range of tidal speeds, ensuring reliable underwater bearings, and mitigating environmental effects on marine life, sediment transport, and navigation.

While Tidewheel remains a niche concept, it is frequently discussed in comparative reviews of marine energy technologies alongside axial-flow tidal turbines and tidal barrages.