The present disclosure provides pumped thermal energy storage systems that can be used to store electrical energy. A pumped thermal energy storage system of the present disclosure can store energy by operating as a heat pump or refrigerator, whereby net work input can be used to transfer heat from the cold side to the hot side. A working fluid of the system is capable of efficient heat exchange with heat storage fluids on a hot side of the system and on a cold side of the system. The system can extract energy by operating as a heat engine transferring heat from the hot side to the cold side, which can result in net work output. Systems of the present disclosure can employ solar heating for improved storage efficiency.

A combined cycle power plant for frequent stops and startups comprises at least one gas turbine, a heat recovery steam generator, at least one steam turbine and a thermal energy storage and retrieval system utilizing latent heat of fusion. Phase change materials receive thermal charge from two sources: (a) renewable energy generation plants, when their production exceeds demand and (b) gas turbine exhaust heat. The thermal energy storage and retrieval system, discharges efficiently thermal energy for steam production, which keeps the at least one steam turbine preheated and ready for fast startups, thus increasing the plant's flexibility and efficiency. A novel two stage latent thermal energy storage system provides at least supercritical steam.

A combined cycle power plant for frequent stops and startups comprises at least one gas turbine, a heat recovery steam generator, at least one steam turbine and a thermal energy storage and retrieval system utilizing latent heat of fusion. Phase change materials receive thermal charge from two sources: (a) renewable energy generation plants, when their production exceeds demand and (b) gas turbine exhaust heat. The thermal energy storage and retrieval system, discharges efficiently thermal energy for steam production, which keeps the at least one steam turbine preheated and ready for fast startups, thus increasing the plant's flexibility and efficiency. A novel two stage latent thermal energy storage system provides at least supercritical steam.

A method of recovering waste heat includes pressurizing a flow of working fluid and transferring heat from a hot gas stream to the flow of working fluid in at least two successively arranged heat transfer sections. At least some of the working fluid is converted to a superheated vapor by the transfer of heat, and passes through an expander to recover useful work. A portion of the flow of working fluid is directed along a branch after having passed through at least one of the heat transfer sections, and bypasses the expander and at least one of the heat transfer sections before being recombined with the working fluid that has passed through the expander. The total flow rate of working fluid can be adjusted to regulate the temperature of the hot gas stream downstream of the heat transfer sections, and the amount of fluid that bypasses along the branch can be adjusted to regulate the temperature of the superheated vapor.

A thermal power plant is described comprising a solar collector field and a heat storage to allow the use of the thermal energy collected by the solar field with a time delay for the production of electricity in the steam power plant.

A device for recovering the waste heat energy having a Clausius-Rankine circuit with a line system conveying a working medium via which at least one vaporizer for vaporizing the working medium, an expansion device for expanding the vaporized working medium to produce mechanical work, a condenser for fluidizing the vaporized and expanded working medium as well as a delivery pump for condensing and conveying the working medium through the line system are fluidically connected to one another. A compensation tank supplies additional working medium volume and is connected to a fluid line and can be fluidically separated from the line system via a valve that is controllable via a control device connected to a sensor for detecting working medium temperature and/or pressure, such that a working medium volume is transferred from the compensation tank into the line system or from the line system into the compensation tank.

A solar energy collector and/or concentrator, a thermal energy storage and retrieval system including the same, and methods of storing and recovering thermal energy are disclosed. The solar energy collector and/or concentrator may include an array of lenses configured to concentrate solar energy, a plurality of conduits through which a heat storage or heat transport fluid flows, and one or more heat transfer elements on each of the conduits, configured to receive the concentrated solar energy from the lenses and transfer the concentrated solar energy to the heat storage/transport fluid. The conduits are configured to move in at least first and second angular dimensions. The thermal energy storage and retrieval system may include the solar energy collector and/or concentrator, a thermodynamic cycle, and a heat storage and retrieval subsystem. Heat is transferred from the heat storage/transport fluid to the heat storage and retrieval subsystem and/or the thermodynamic cycle.

A method for operating a steam turbine plant including a steam turbine and a steam generator allows a power reserve to be provided whilst simultaneously maintaining a high level of efficiency in the normal mode of operation. The steam turbine plant includes a heat reservoir which is associated with the steam turbine, from which the steam is removed and is fed to the steam turbine. The steam is fed to the steam turbine when the steam generator is not in operation.

An energy storage device for storing energy including: a high-temperature regenerator containing a storage material and a working gas as heat transfer medium for the purpose of exchanging heat between the storage material and the traversing working gas, a closed charging circuit for the working gas, including a first compressor, a first expander, a first recuperator having a first and a second heat exchange duct, the high-temperature regenerator and a pre-heater, wherein the first compressor is coupled to the first expander by a shaft, a discharging circuit for the working gas, and including a switch that selectively connects the high-temperature regenerator to either the charging circuit or the discharging circuit, such that the circuit containing the high-temperature regenerator forms a closed circuit.

Cryogenic energy storage systems, and particularly methods for capturing cold energy and re-using that captured cold energy, are disclosed. The systems allow cold thermal energy from the power recovery process of a cryogenic energy storage system to be captured effectively, to be stored, and to be effectively utilised. The captured cold energy could be reused in any co-located process, for example to enhance the efficiency of production of the cryogen, to enhance the efficiency of production of liquid natural gas, and/or to provide refrigeration. The systems are such that the cold energy can be stored at very low pressures, cold energy can be recovered from various components of the system, and/or cold energy can be stored in more than one thermal store.