PLANT CONTROL METHOD, PLANT CONTROL DEVICE, PROGRAM, AND PLANT

In the present invention, a first supply standard quantity indicating the hydrogen quantity to be supplied to a second production device (40) is determined. It is determined whether the remaining hydrogen quantity in a storage device (20) at the start of a target term is within a standard range. (1) If the remaining hydrogen quantity is within the standard range, (1-a) in a case where the first supply standard quantity is within a range of a consumption lower limit value to a consumption upper limit value regarding hydrogen consumption in the second production device (40), then control is performed such that the first supply standard quantity is set as the hydrogen supply quantity from the storage device (20) to the second production device (40). (2) If the remaining hydrogen quantity is not within the standard range, a second supply standard quantity, which is a standard for the hydrogen supply quantity to the second production device (40) such that the remaining hydrogen quantity in the storage device (20) when the target term ends is within the standard range, is determined, and (2-a) in a case where the second supply standard quantity is within the range of the consumption lower limit value to the consumption upper limit value with respect to hydrogen consumption in the second production device (40), then the second supply standard quantity is set as the hydrogen supply quantity from the storage device (20) to the second production device (40).