According to an embodiment of the present invention, a tidal power generator may comprise: a plurality of channel levees which are arranged spaced apart from each other so as to form a channel having a constant width and which have a plurality of installation grooves, each being formed by recessing the surface facing the channel, wherein a tidal current can move forward/backward in the channel; a first water collection levee extending from the front end of the channel levees with reference to a movement direction of the tidal current and having a peak shape of which the width is gradually reduced towards the front side of the channel; a second water collection levee extending from the rear end of the channel levees with reference to the movement direction of the tidal current and having a peak shape of which the width is gradually reduced towards the rear side of the channel; and a waterwheel module which is inserted and installed in the installation groove and can generate power using movements of the tidal current.

The present application includes a system for generating energy via a rotating drum. The system includes a housing, a drum, and a plurality of enclosed chambers. The housing surrounds the drum and helps to distinguish between a gravitational domain and a buoyancy domain. The drum is coupled to a shaft and configured to rotate within the housing about a central axis. The plurality of enclosed chambers are radially aligned around an internal surface of the drum. The drum is exposed to a gravitational domain and a buoyancy domain simultaneously so as to induce rotation of the drum around the shaft. The enclosed chambers are subjected to gravitational forces in the gravitational domain and the enclosed chambers are subjected to buoyancy forces in the buoyancy domain.

The present application includes a system for generating energy via a rotating drum. The system includes a housing, a drum, and a plurality of enclosed chambers. The housing surrounds the drum and helps to distinguish between a gravitational domain and a buoyancy domain. The drum is coupled to a shaft and configured to rotate within the housing about a central axis. The plurality of enclosed chambers are radially aligned around an internal surface of the drum. The drum is exposed to a gravitational domain and a buoyancy domain simultaneously so as to induce rotation of the drum around the shaft. The enclosed chambers are subjected to gravitational forces in the gravitational domain and the enclosed chambers are subjected to buoyancy forces in the buoyancy domain.

The invention relates to energy generation and water conservation. There are many water systems which might lend themselves to energy extraction, such as canal systems. However, despite canal systems being around for hundreds of years, practical solutions for using the energy available have not been developed. The invention provides, among various examples, a system which can be associated with a lock in a canal and provides a flow control strategy responsive to water availability upstream of the lock. Thus electricity may be generated selectively in response to the lock state and energy demands but without adversely affecting the canal system by taking excess water. The system may be applied to multiple locks and may incorporate machine learning to evolve a strategy for a canal based on lock usage and energy demand.

The invention relates to energy generation and water conservation. There are many water systems which might lend themselves to energy extraction, such as canal systems. However, despite canal systems being around for hundreds of years, practical solutions for using the energy available have not been developed. The invention provides, among various examples, a system which can be associated with a lock in a canal and provides a flow control strategy responsive to water availability upstream of the lock. Thus electricity may be generated selectively in response to the lock state and energy demands but without adversely affecting the canal system by taking excess water. The system may be applied to multiple locks and may incorporate machine learning to evolve a strategy for a canal based on lock usage and energy demand.

The invention concerns a method for starting a hydroelectric turbine (10) in a pumping mode, said turbine being provided with a runner (6) mechanically coupled to a shaft line (8) and a variable speed electric motor connected to a grid, a distributor (4) comprising guide vanes to control a flow of water to said runner, the method comprising: a) a step of operating the variable speed motor at least partly at fixed speed, said guide vanes being only partially opened, and of defining or calculating: data of a plurality of hydraulic characteristics (C.sub.1, C.sub.2, C.sub.i) of the turbine for an operation without cavitation; data of an operation range of the electric motor, giving the speed of the motor as a function of its power; b) then a step of operating the turbine in a power control mode.

The invention concerns a method for starting a hydroelectric turbine (10) in a pumping mode, said turbine being provided with a runner (6) mechanically coupled to a shaft line (8) and a variable speed electric motor connected to a grid, a distributor (4) comprising guide vanes to control a flow of water to said runner, the method comprising: a) a step of operating the variable speed motor at least partly at fixed speed, said guide vanes being only partially opened, and of defining or calculating: data of a plurality of hydraulic characteristics (C.sub.1, C.sub.2, C.sub.i) of the turbine for an operation without cavitation; data of an operation range of the electric motor, giving the speed of the motor as a function of its power; b) then a step of operating the turbine in a power control mode.

A method for using a pressure exchanger to reduce flow as a choke that includes receiving a flow of high pressure fluid at the pressure exchanger, filling a chamber of the pressure exchanger with high pressure fluid, and discharging a portion of the fluid in the chamber at a low pressure.

The present invention relates to a method of operating a fluid-working machine wherein the volume of working fluid displaced each cycle is selectable and wherein the volume of working fluid displaced by a first working chamber takes into account the suitability of the working chamber to displace fluid. The invention extends in further aspects to power absorbing structures such as renewable energy devices comprising such fluid working machines. The invention allows the operation of fluid working machines and power absorbing structures which are more long lived.

A wave energy converter comprises a submerged buoyant vessel (10) that can react directly with the seabed using neutrally buoyant taut tethers (19) at depths that characterize the continental shelf. The vessel (10) is held by a taut vertical mooring line (12) of controllable length and a taut vertical upper line (17) of controllable length connected to a surface float (15). These lines (12, 17) have elastic sections, allowing the vessel (10) to follow an orbital path in response to swell from any direction. By varying the length of these lines (12, 17) the submersion of the vessel (10) can be varied dynamically according to wave height. By varying the tension of these lines (12, 17) the natural oscillation period of the vessel (10) can be varied dynamically in response to the swell period.