Power system

A power system comprising:

• a storage battery, wherein the storage battery has a maximum electric power Wsix which can be charged;
• a water electrolyzer, wherein the water electrolyzer can receive a maximum electric power Whix;
• a fuel cell that generates electricity using hydrogen supplied from a hydrogen reservoir that stores hydrogen generated by the water electrolyzer;
• a power generation device using renewable energy;
• and
• a controller including a processor and a memory circuit storing a control program, wherein the control program, when executed by the processor, causes the controller to:
• cause a detector to detect whether there is a person in a building, determine whether a surplus of electric power Ws of the power generation device is smaller than the maximum electric power Wsix of the storage battery or the maximum electric power Whix that the water electrolyzer can receive, determine whether a power load WO of the building is smaller than a maximum electric power Wsox of the storage battery that can be discharged or a maximum electric power Whox that the fuel cell can generate and to output detection results, and
• perform at least one of first control and second control,
• the first control comprises determining a priority between the storage battery and the water electrolyzer, as a destination to which electric power is supplied from a power generation device using renewable energy, based on the detection results detected by the detector that whether there is a person in a building and whether a surplus of electric power Ws of the power generation device is smaller than the maximum electric power Wsix of the storage battery or the maximum electric power Whix that the water electrolyzer can receive, and cause the storage battery or water electrolyzer to receive the electric power from the power generation device, in the first control, and
• the second control comprises determining a priority between the storage battery and the fuel cell, as a source from which electric power is supplied to a power load provided in the building, based on the detection results detected by the detector whether there is a person in a building and whether the power load WO of the building is smaller than the maximum electric power Wsox of the storage battery or the maximum electric power Whox that the fuel cell can generate, and cause the fuel cell or the storage battery to supply the electric power to the power load, in the second control.