A control method comprises: receiving from a first vehicle, first information including a first required amount of the energy source; receiving from a second vehicle, second information including a second required amount of the energy source; and determining, when a total sum of required amounts of the energy source received from two or more vehicles including the first vehicle and the second vehicle is larger than a remaining amount in a storage reservoir, i) a first reserved supply amount of the energy source for the first vehicle, wherein the first reserved supply amount is smaller than the first required amount, and ii) a second reserved supply amount of the energy source for the second vehicle. The second reserved supply amount is determined within a range where a total sum of the first reserved supply amount and the second reserved supply amount does not exceed the remaining amount.