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).

A system for providing supercritical steam including a first boiler that generates steam via combusting a first fuel, and a second boiler fluidly connected to the first boiler via a conduit which heats the generated steam to supercritical steam temperatures via combusting a second fuel. A first temperature of the conduit may be below a critical corrosion temperature and a second temperature of the conduit is greater than or equal to the critical corrosion temperature. A combined carbon emission rate of the first boiler and the second boiler may be less than a combined carbon emission rate of generating and heating the steam to supercritical steam temperatures using boilers that only combust the first fuel. The first boiler may be fluidly connected to a heat exchanger that heats the generated steam to a supercritical steam temperature via a flue gas produced by a gas turbine.

A system for providing supercritical steam including a first boiler that generates steam via combusting a first fuel, and a second boiler fluidly connected to the first boiler via a conduit which heats the generated steam to supercritical steam temperatures via combusting a second fuel. A first temperature of the conduit may be below a critical corrosion temperature and a second temperature of the conduit is greater than or equal to the critical corrosion temperature. A combined carbon emission rate of the first boiler and the second boiler may be less than a combined carbon emission rate of generating and heating the steam to supercritical steam temperatures using boilers that only combust the first fuel. The first boiler may be fluidly connected to a heat exchanger that heats the generated steam to a supercritical steam temperature via a flue gas produced by a gas turbine.

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.

A power plant comprises supplies of hydrogen fuel, oxygen fuel and water, a boiler comprising a burner for combusting hydrogen and oxygen to produce heat, combustion products and low/intermediate-pressure steam and a first heat exchanger configured to heat water to generate high-pressure steam, and a steam turbine comprising a first turbine configured to be driven only with the high-pressure steam to provide input to a first electrical generator and a second turbine configured to be driven by low/intermediate-pressure steam from the boiler. A method of operating a steam plant comprises combusting hydrogen fuel in a boiler to produce combustion products and LP/IP steam, turning a turbine with the combustion products, condensing water from the combustion products in a condenser, heating water from the condenser in a heat exchanger within the boiler to produce HP steam and turning a turbine with the steam from the first heat exchanger.

A power plant comprises supplies of hydrogen fuel, oxygen fuel and water, a boiler comprising a burner for combusting hydrogen and oxygen to produce heat, combustion products and low/intermediate-pressure steam and a first heat exchanger configured to heat water to generate high-pressure steam, and a steam turbine comprising a first turbine configured to be driven only with the high-pressure steam to provide input to a first electrical generator and a second turbine configured to be driven by low/intermediate-pressure steam from the boiler. A method of operating a steam plant comprises combusting hydrogen fuel in a boiler to produce combustion products and LP/IP steam, turning a turbine with the combustion products, condensing water from the combustion products in a condenser, heating water from the condenser in a heat exchanger within the boiler to produce HP steam and turning a turbine with the steam from the first heat exchanger.

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.

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.