The invention relates generally to methods and apparatus for integration of renewable and conventional energy to enhance electric reliability and reduce fuel consumption and emissions via thermal energy storage.

A CO.sub.2 power generation system includes a furnace to burn fuel, a turbine operated by a working fluid supplied thereto, the working fluid being heated by heat generated in the furnace, a recuperator exchanging heat with the working fluid passing through the turbine, a cooler to cool the working fluid passing through the recuperator, and a compressor to compress the working fluid passing through the cooler, wherein the working fluid passing through the compressor is circulated to the furnace, and the working fluid is supercritical CO.sub.2.

A CO.sub.2 power generation system includes a furnace to burn fuel, a turbine operated by a working fluid supplied thereto, the working fluid being heated by heat generated in the furnace, a recuperator exchanging heat with the working fluid passing through the turbine, a cooler to cool the working fluid passing through the recuperator, and a compressor to compress the working fluid passing through the cooler, wherein the working fluid passing through the compressor is circulated to the furnace, and the working fluid is supercritical CO.sub.2.

In a gas turbine system including a first gas turbine generator, a heat recovery steam generator and a steam turbine generator heat rejection system, the present invention relates to a method for CO.sub.2 capture from flue gas in said system, said method including: (a) diverting an amount of heat recovery steam generator flue gas from the CO.sub.2 capture plant; and (b) mixing the diverted heat recovery steam generator flue gas with an air stream, forming a combined gas stream, wherein (1) the combined gas stream is fed to a second gas turbine generator; (2) exhaust gas from the second gas turbine generator is mixed with exhaust gas from the first gas turbine generator, forming a combined exhaust gas stream; and (3) the combined exhaust gas stream enters the heat recovery steam generator, with the CO.sub.2 content of the combined exhaust gas stream increased through supplementary firing in the heat recovery steam generator.

In a gas turbine system including a first gas turbine generator, a heat recovery steam generator and a steam turbine generator heat rejection system, the present invention relates to a method for CO.sub.2 capture from flue gas in said system, said method including: (a) diverting an amount of heat recovery steam generator flue gas from the CO.sub.2 capture plant; and (b) mixing the diverted heat recovery steam generator flue gas with an air stream, forming a combined gas stream, wherein (1) the combined gas stream is fed to a second gas turbine generator; (2) exhaust gas from the second gas turbine generator is mixed with exhaust gas from the first gas turbine generator, forming a combined exhaust gas stream; and (3) the combined exhaust gas stream enters the heat recovery steam generator, with the CO.sub.2 content of the combined exhaust gas stream increased through supplementary firing in the heat recovery steam generator.

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 network 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 network output. Systems of the present disclosure can employ solar heating for improved storage efficiency.

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 network 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 network output. Systems of the present disclosure can employ solar heating for improved storage efficiency.

Provided is a hydrogen production system including a thermal energy storage having a housing, a storage chamber with heat storage material inside the storage chamber and a fluid inlet port fluidically connected to the storage chamber and a fluid outlet port fluidically connected to the storage chamber, and at least one high temperature electrolyser for producing hydrogen, whereby the at least one high temperature electrolyser is thermally connected to the heat storage material of the storage chamber of the thermal energy storage. Several modes of operation are defined. A method for producing hydrogen in the hydrogen production system is also provided.

A coal-fired power generation system and a supercritical CO.sub.2 cycle system thereof are provided. The supercritical CO.sub.2 cycle system includes a compressor unit and a turbine unit. The turbine unit includes a preceding stage heater, a preceding stage turbine, a last stage heater and a last stage turbine successively connected in series. An exhaust port of at least one of compressors in the compressor unit is in communication with the turbine unit through a split flow pipe, and a communication position between the split flow pipe and the turbine unit is located downstream of a suction port of the preceding stage turbine. An auxiliary regenerator and an auxiliary heater are provided at the split flow pipe, and the auxiliary regenerator is located upstream of the auxiliary heater.

An arrangement for storing energy, the arrangement comprising a heat-charging mass (4) and a heat-transfer channeling (3), the arrangement also comprising a heating member (11) adapted to heat up the heat-charging mass (4). The arrangement comprises a boiler belonging to a discarded combustion power plant and converted to a thermal energy storage (2) by at least partly filling the boiler with the heat-charging mass (4).