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.

A system for generating electrical energy from the wave motion of the sea is provided with electrical-energy generating means for exploiting the wave motion of the sea in order to generate electrical energy. A floating body is provided with equipment designed to regulate the frequency of the resonance peak of the system.

A system for generating electrical energy from the wave motion of the sea is provided with electrical-energy generating means for exploiting the wave motion of the sea in order to generate electrical energy. A floating body is provided with equipment designed to regulate the frequency of the resonance peak of the system.

A method and device for non-emission electric energy production, consisting in: generating negative pressure or vacuum inside a pressure vessel in its upper part constituting a vacuum chamber in whose space a turbine rotor is situated; setting a height of a liquid or water column in the lower part of the pressure vessel constituting a liquid or water column below the turbine rotor, wherein the vacuum chamber is directly connected with the liquid or water chamber situated below the vacuum chamber, and a conventional interface between them is determined by the upper surface of the liquid or water column; closing a first closing means and supplying a liquid or water by a means for supplying a liquid or water to the vacuum chamber.

A hydroelectric power generation system includes: a generator driven by the hydraulic turbine; a head adjuster adjusting an effective head of the hydraulic turbine; and a controller cooperatively executing: flow rate control for controlling the generator such that a flow rate in the hydraulic turbine is brought close to a target flow rate; and head adjusting control for adjusting the effective head of the hydraulic turbine using the head adjuster such that the effective head of the hydraulic turbine falls within a first range.

This invention regards a hydraulic turbine (1) to operate in pressure circuits, where there is a flow of a fluid, to control the flow and pressure downstream the installation point. Even so, said turbine (1) can generate power for itself based on the difference of pressure and flow, as the remaining power can be used in public power networks or isolated. Its application field comprises sanitation companies, beverage industries, paper and cellulose industries, petrochemical companies or any places, where it is needed to control the flow and pressure in supply networks.

This invention regards a hydraulic turbine (1) to operate in pressure circuits, where there is a flow of a fluid, to control the flow and pressure downstream the installation point. Even so, said turbine (1) can generate power for itself based on the difference of pressure and flow, as the remaining power can be used in public power networks or isolated. Its application field comprises sanitation companies, beverage industries, paper and cellulose industries, petrochemical companies or any places, where it is needed to control the flow and pressure in supply networks.

A multi-mode subterranean energy system and a related multi-mode subterranean energy production method are disclosed. The system comprises subterranean tunnels (2, 3, 8, 9, 14) connecting an upper reservoir of water (1), an underground cavity (10) and a subterranean recipient (15), a turbine/pump unit (4), and water flow control means (5, 6, 7). The system optionally can be operated in four modes.

A multi-mode subterranean energy system and a related multi-mode subterranean energy production method are disclosed. The system comprises subterranean tunnels (2, 3, 8, 9, 14) connecting an upper reservoir of water (1), an underground cavity (10) and a subterranean recipient (15), a turbine/pump unit (4), and water flow control means (5, 6, 7). The system optionally can be operated in four modes.

The invention provides a pumped storage system with waterfall control subsystem, architected to enable optimized achievement of two primary goals in the context of a geography with upper and lower water bodies such as lakes, which are connected by a river with a waterfall. The first primary goal comprises energy storage utilizing a pumped storage system between two water bodies of different elevation, which can store energy from excess power production periods and return that energy by producing power to fill needs during deficit power production periods. The second primary goal comprises touristic value & waterfall viewer satisfaction combined with environmental & ecological objectives. A multiobjective control subsystem is utilized for synthesis of time-domain control commands aimed towards optimized achievement of the aforesaid two primary goals, and for control of the pumped storage system with waterfall control subsystem responsive to these time-domain control commands.