An example method may comprise providing a composite pumped thermal system having a plurality of subunits, each configured for operation in a thermal storage mode and a power generation mode; operating the system in power output mode with a power output level at an intermediate output level between 0% and 100% of a maximum output level of the system; reducing the power output level to 0% of the maximum output level by reducing a power output of a first subunit operating in a power generation mode; and at 0% of the maximum output level, wherein a power input level of the system is also at 0% of a maximum input level of the system, increasing the power input level to an intermediate input level between 0% and 100% of the maximum input level by increasing a power input of a second subunit operating in a thermal storage mode.

An example method may comprise providing a composite pumped thermal system having a plurality of subunits, each configured for operation in a thermal storage mode and a power generation mode; operating the system in power output mode with a power output level at an intermediate output level between 0% and 100% of a maximum output level of the system; reducing the power output level to 0% of the maximum output level by reducing a power output of a first subunit operating in a power generation mode; and at 0% of the maximum output level, wherein a power input level of the system is also at 0% of a maximum input level of the system, increasing the power input level to an intermediate input level between 0% and 100% of the maximum input level by increasing a power input of a second subunit operating in a thermal storage mode.

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.

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 dual closed loop electric generating system, having a gas turbine assembly (having a combustion chamber, a compressor, a first pump, a first driveshaft, a gas turbine and a first generator) and a steam turbine assembly (having a second pump, a second driveshaft, a steam turbine and a second generator). The first portion of the working fluid circulates through the gas turbine assembly and a first heat exchanger. The second portion of the working fluid circulates through the steam turbine assembly and the first heat exchanger. The first heat exchanger transfers a first heat energy from the gas turbine loop to the steam turbine loop. The gas turbine assembly generates a first portion of an electric output. The steam turbine assembly generates a second portion of the electric output.

A combined cycle dual closed loop electric generating system, having a gas turbine assembly (having a combustion chamber, a compressor, a first pump, a first driveshaft, a gas turbine and a first generator) and a steam turbine assembly (having a second pump, a second driveshaft, a steam turbine and a second generator). The first portion of the working fluid circulates through the gas turbine assembly and a first heat exchanger. The second portion of the working fluid circulates through the steam turbine assembly and the first heat exchanger. The first heat exchanger transfers a first heat energy from the gas turbine loop to the steam turbine loop. The gas turbine assembly generates a first portion of an electric output. The steam turbine assembly generates a second portion of the electric output.

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 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.

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.