Patent ID: 7464551

Claim:
A method for operating a power generation plant in an electricity grid, the power generation plant including, at least one storage volume for storing an energy storage fluid therein, at least one power generation machine for operation with energy storage fluid, the power generation machine drivingly connected to a generator and capable of supplying electric power output via the generator during operation, at least one power consuming machine for feeding energy storage fluid into the storage volume, the power consuming machine drivingly connected to a motor and consuming power during operation via the motor, the method comprising: simultaneously feeding energy storage fluid into said storage volume with said at least one power consuming machine and operating said at least one power generation machine with said energy storage fluid; and supplying a net power output (P NET ) as the difference between the power output generated by the power generation machine and the power consumed by (P_) the motor of the at least one power consuming machine, said supplying a net power output comprising operating the power generation plant in a first operating mode at a first grid power demand, the first operation made including operating the power generation machine with a first power output and operating the power consuming machine with a first power consumption; and upon a change of the power demand to a second power demand, matching the net power output of the power generation plant to the second power demand by changing the power consumption of the power consuming machine.