Power management server and power management method

A power management method, comprising:

• selecting, based on a predetermined standard, from among a plurality of facilities including a distributed power supply, a first facility in which first processing is applied to the distributed power supply and a second facility in which second processing is applied to the distributed power supply;
• and
• configuring a first margin which is added to a contracted power amount based on an estimated demand power of the plurality of facilities,
• wherein the first processing is processing of controlling an output power of the distributed power supply by using a first target value as a target value for purchased power purchased by the facility from a power provider,
• the second processing is processing of controlling the output power of the distributed power supply by using a second target value as the target value for the purchased power, the second target value being greater than the first target value,
• the selecting the first facility and the second facility includes selecting a candidate of the first facility and the second facility until a secured power amount exceeds a margin threshold value which is obtained by adding the first margin to the contracted power amount,
• the contracted power amount is a power amount which is established to be reduced from a baseline power as all of the plurality of facilities, and
• the secured power amount is a total power amount which can be reduced from the baseline power of facilities selected as the candidate of the first facility and the second facility.