Systems and methods relating to use of external air for inventory control of a closed thermodynamic cycle system or energy storage system, such as a reversible Brayton cycle system, are disclosed. A method may involve, in a closed cycle system operating in a power generation mode, circulating a working fluid may through a closed cycle fluid path. The closed cycle fluid path may include a high pressure leg and a low pressure leg. The method may further involve in response to a demand for increased power generation, compressing and dehumidifying environmental air. And the method may involve injecting the compressed and dehumidified environmental air into the low pressure leg.

Systems and methods relating to use of external air for inventory control of a closed thermodynamic cycle system or energy storage system, such as a reversible Brayton cycle system, are disclosed. A method may involve, in a closed cycle system operating in a power generation mode, circulating a working fluid may through a closed cycle fluid path. The closed cycle fluid path may include a high pressure leg and a low pressure leg. The method may further involve in response to a demand for increased power generation, compressing and dehumidifying environmental air. And the method may involve injecting the compressed and dehumidified environmental air into the low pressure leg.

In a cryogenic combined cycle power plant electric power drives a cryogenic refrigerator to store energy by cooling air to a liquid state for storage within tanks, followed by subsequent release of the stored energy by first pressurizing the liquid air, then regasifying the liquid air and raising the temperature of the regasified air at least in part with heat exhausted from a combustion turbine, and then expanding the heated regasified air through a hot gas expander to generate power. The expanded regasified air exhausted from the expander may be used to cool and make denser the inlet air to the combustion turbine. The combustion turbine exhaust gases may be used to drive an organic Rankine bottoming cycle. An alternative source of heat such as thermal storage, for example, may be used in place of or in addition to the combustion turbine.

A system for air compression, storage and expansion may include a low-pressure and a high-pressure compressor, a motor, a heat storage, an air storage volume, a high-pressure and a low-pressure turbine, and a generator. The system may further include a first air path connecting sequentially the low-pressure compressor, the heat storage, the high-pressure compressor, and the air storage volume. The system may further include a second air path connecting sequentially the air storage volume, the high-pressure turbine, the heat storage, and the low-pressure turbine.

A system for air compression, storage and expansion may include a low-pressure and a high-pressure compressor, a motor, a heat storage, an air storage volume, a high-pressure and a low-pressure turbine, and a generator. The system may further include a first air path connecting sequentially the low-pressure compressor, the heat storage, the high-pressure compressor, and the air storage volume. The system may further include a second air path connecting sequentially the air storage volume, the high-pressure turbine, the heat storage, and the low-pressure turbine.

A system and method provide integrated carbon-negative, geothermal-based, energy generation and storage. The embodiments produce dispatchable electricity at grid-scale by storing excess energy from the grid and generating its own energy. The excess energy may be taken from solar and wind sources. In one aspect, the subject technology is energy storage, energy generation, carbon utilization and sequestration, all in one. The technology has very high round-trip efficiency of storing energy and is carbon-negative which makes it far more sustainable than any competing energy storage technology.

A system and method provide integrated carbon-negative, geothermal-based, energy generation and storage. The embodiments produce dispatchable electricity at grid-scale by storing excess energy from the grid and generating its own energy. The excess energy may be taken from solar and wind sources. In one aspect, the subject technology is energy storage, energy generation, carbon utilization and sequestration, all in one. The technology has very high round-trip efficiency of storing energy and is carbon-negative which makes it far more sustainable than any competing energy storage technology.

A thermal storage subsystem may include at least a first storage reservoir configured to contain a thermal storage liquid at a storage pressure that is greater than atmospheric pressure. A liquid passage may have an inlet connectable to a thermal storage liquid source and configured to convey the thermal storage liquid to the liquid reservoir. A first heat exchanger may be provided in the liquid inlet passage and may be in fluid communication between the first compression stage and the accumulator, whereby thermal energy can be transferred from a compressed gas stream exiting a gas compressor/expander subsystem to the thermal storage liquid.

A thermal storage subsystem may include at least a first storage reservoir configured to contain a thermal storage liquid at a storage pressure that is greater than atmospheric pressure. A liquid passage may have an inlet connectable to a thermal storage liquid source and configured to convey the thermal storage liquid to the liquid reservoir. A first heat exchanger may be provided in the liquid inlet passage and may be in fluid communication between the first compression stage and the accumulator, whereby thermal energy can be transferred from a compressed gas stream exiting a gas compressor/expander subsystem to the thermal storage liquid.

Operating coal fired energy systems. A method of operating a coal fired energy system comprises operating a coal fired steam generator comprising a coal feed system and a main air feed system to provide a coal-air mixture as a heating source for a boiler for generating steam. The method includes operating an auxiliary air compression system comprising a fueled engine coupled to a compressor for providing an auxiliary supply of compressed air to a soot blower of the coal-fired steam generator. The method comprises injecting the auxiliary supply of compressed air along walls of the boiler to remove soot and ash buildup from the boiler.