A power plant, including an internal combustion engine, a fuel conversion device that coverts a fuel to be supplied to the internal combustion engine from a before-conversion fuel to an after-conversion fuel, a first fuel supply device that supplies the fuel conversion device with the before-conversion fuel, a second fuel supply device that supplies the internal combustion engine with the after-conversion fuel, the after-conversion fuel being the fuel that has been converted by the fuel conversion device, and a controller that is communicated with the internal combustion engine, the fuel conversion device, the first fuel supply device and the second fuel supply device. The controller is configured to supply the fuel conversion device with the before-conversion fuel by operating the first fuel supply device, control the temperature of the fuel conversion device in a first temperature range to evaporate the before-conversion fuel to produce a first after-conversion fuel, control the temperature of the fuel conversion device in a second temperature range to reform the before-conversion fuel to produce a second after-conversion fuel, and supply the internal combustion engine with the after-conversion fuel by operating the second fuel supply device.