Embodiments of the disclosure provide a method for operating a combined cycle power plant (CCPP). The method may include creating a variant control profile for the CCPP for a power plant model of the CCPP. The method may include modifying the variant control profile in response to the variant control profile not reducing the fuel consumption or meeting the quality threshold. The method may also include adjusting the CCPP to use the variant control profile in response to the variant control profile reducing the fuel consumption and meeting the quality threshold. Using the variant control profile adjusts a turbine section inlet temperature schedule or an exhaust temperature schedule for the CCPP.

The present disclosure provides pumped thermal energy storage systems that can be used to store and extract 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.

The present disclosure provides pumped thermal energy storage systems that can be used to store and extract 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.

A power generation assembly and related methods to enhance power efficiency and reduce greenhouse gas emissions associated with a power-dependent operation, may include a gas turbine engine. The power generation assembly also may include a heat exchanger positioned to receive exhaust gas from the gas turbine engine during operation. The heat exchanger may include an exhaust gas inlet positioned to receive exhaust gas and a liquid inlet positioned to receive liquid. The heat exchanger may be positioned to convert liquid into steam via heat from the exhaust gas. The power generation assembly further may include a steam turbine positioned to receive steam from the heat exchanger and convert energy from the steam into mechanical power. The power generation assembly still further may include an electric power generation device connected to the steam turbine and positioned to convert the mechanical power from the steam turbine into electrical power.

A power generation assembly and related methods to enhance power efficiency and reduce greenhouse gas emissions associated with a power-dependent operation, may include a gas turbine engine. The power generation assembly also may include a heat exchanger positioned to receive exhaust gas from the gas turbine engine during operation. The heat exchanger may include an exhaust gas inlet positioned to receive exhaust gas and a liquid inlet positioned to receive liquid. The heat exchanger may be positioned to convert liquid into steam via heat from the exhaust gas. The power generation assembly further may include a steam turbine positioned to receive steam from the heat exchanger and convert energy from the steam into mechanical power. The power generation assembly still further may include an electric power generation device connected to the steam turbine and positioned to convert the mechanical power from the steam turbine into electrical power.

A fast HRSG starting method and apparatus for combined cycles requiring frequent cycling, baseload and backup power; preventing grid failure from variables of wind and solar power. A once-through HRSG, eliminating all except two hot thick wall components: the high pressure superheater and reheater headers. The method fills the high pressure superheater with boilerwater; whereby steam is generated in starting as thick header's and tube's ramp-up together at saturation temperatures as the gas turbine attains synchronous speed No-Load; reducing conventional thermal stress failures loss of availability and costly repairs. At gas turbine full power dry steam is generated by the high pressure superheater at low allowable temperature start and load the steam turbine and protect the reheater. The dryout zone in the high pressure superheater is controlled loading the steam turbine faster than conventional without problematic attemperators, thereby decreasing: thermal stresses, fuel, emissions and possible ingestion of spray-water.

A fast HRSG starting method and apparatus for combined cycles requiring frequent cycling, baseload and backup power; preventing grid failure from variables of wind and solar power. A once-through HRSG, eliminating all except two hot thick wall components: the high pressure superheater and reheater headers. The method fills the high pressure superheater with boilerwater; whereby steam is generated in starting as thick header's and tube's ramp-up together at saturation temperatures as the gas turbine attains synchronous speed No-Load; reducing conventional thermal stress failures loss of availability and costly repairs. At gas turbine full power dry steam is generated by the high pressure superheater at low allowable temperature start and load the steam turbine and protect the reheater. The dryout zone in the high pressure superheater is controlled loading the steam turbine faster than conventional without problematic attemperators, thereby decreasing: thermal stresses, fuel, emissions and possible ingestion of spray-water.

Extra heat in a closed cycle power generation system, such as a reversible closed Brayton cycle system, may be dissipated between discharge and charge cycles. An extra cooling heat exchanger may be added on the discharge cycle and disposed between a cold side heat exchanger and a compressor inlet. Additionally or alternatively, a cold thermal storage medium passing through the cold side heat exchanger may be allowed to heat up to a higher temperature during the discharge cycle than is needed on input to the charge cycle and the excess heat then dissipated to the atmosphere.

Extra heat in a closed cycle power generation system, such as a reversible closed Brayton cycle system, may be dissipated between discharge and charge cycles. An extra cooling heat exchanger may be added on the discharge cycle and disposed between a cold side heat exchanger and a compressor inlet. Additionally or alternatively, a cold thermal storage medium passing through the cold side heat exchanger may be allowed to heat up to a higher temperature during the discharge cycle than is needed on input to the charge cycle and the excess heat then dissipated to the atmosphere.

A mechanical energy generation system with an energy recovery, includes at least one heating volume, wherein a liquid fluid stored in the at least one heating volume, at least one heat exchanger element or a heating fluid allows a heat to be changed to the liquid fluid inside the at least one heating volume, at least one outlet line allows the liquid fluid and/or a gas fluid to exit in a pressurized state when the liquid fluid and/or the gas fluid is compressed inside the at least one heating volume when the liquid fluid transitions partially into a gas phase and the at least one outlet line allows resulting a mechanical energy and at least one feed line allows the liquid fluid to be fed into the at least one heating volume, and an embodiment of the mechanical energy generation system comprising at least a second closed volume.